HP 8340A Service Manual
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HP 8340A Service Manual

Synthesized sweeper 10 mhz to 26.5 ghz
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Summary of Contents for HP 8340A

  • Page 1 Scans by HB9HCA and HB9FSX...

  • Page 2: Table Of Contents

    ...... 8-38 Safety Considerations ....8-7 Overall Instrument Troubleshooting ..8-41 General Information ....8-8 Repair Procedures ....8-55 8340A Overall Instrument Theory ..8-10 Module Exchange Program ..8-57 Calibration Constants ....8-15 After Service Safety Checks .... 8-58 Troubleshooting Aids ....

  • Page 3: Safety Considerations

    SAFETY CONSIDERATIONS SAFETY EARTH GROUND GENERAL This is a Safety Class I product (provided with a This product and related documentation must be protective earthing terminal). An uninterruptible reviewed for familiarization with safety markings safety earth ground must be provided from the and instructions before operation.
  • Page 4 REFERENCE GUIDE TO SERVICE DOCUMENTATION Description Bottom View Alpha Display • Display Driver • Display Processor • Not Assigned Keyboard • @)@) Keyboard Interface • Lower Keyboard • 3.7 GHz Oscillator Band Pulse Modulator Directional Coupler Band 1-4 Detector Band 0 Splitter/Detector ®...

  • Page 5: Service

    "SERVICE SECTION FORMAT" description, below. The HP 8340A Service Section is divided into eight sub-sections called functional groups. Four of these are listed on the front of each Service section tab along with a chart that shows which individual assemblies they contain and where these assemblies are located.

  • Page 6: Service Section Format

    Model 8340A - Service SERVICE SECTION FORMAT INTRODUCTION 8340A Service Section is structured to minimize the time it takes to troubleshoot a problem. The following text describes the format of the Service Section and provides important information concerning its use.
  • Page 7 Scans by HB9HCA and HB9FSX...
  • Page 8 Model 8340A - Service SERVICE INTRODUCTION GENERAL INFORMATION INSTRUMENT THEORY TROUBLESHOOTING AIDS INSTRUMENT TROUBLESHOOT ING REPAIR SCHEMATIC SYMBOLOGY CONTROLLER SECTION G REFERENCE LOOP LOOP B OVERALL THEORY OVERALL THEORY TROUBLESHOOTING TROUBLESHOOTING TO ASSEMBLY LEVEL TO ASSEMBLY LEVEL INDIVIDUAL ASSEMBLY INDIVIDUAL ASSEMBLY...
  • Page 9 Model 8340A Service WARNING When connected to ac mains, there are voltages at points inside the instrument that can cause personal injury or even death. Any servicing of this instrument with protective covers removed should be performed only by trained personnel who are aware of the hazard involved.

  • Page 10: General Information

    The Ungar HOT VAC or equivalent is recommended for removing motherboard connectors. Other than these items, no special equipment is needed that isn't provided in the Service Kit (HP Part Number 08340-60134). Table 8A-1 is a list of the tools included in this kit: Table 8A-l.
  • Page 11 All interconnect cables and their associated connectors are listed in Table 8E-1, located within the A62 Motherboard Functional Group. Table 8E-1 alphabetically lists and defines all HP 8340A signal mnemonics, references the point­ to-point distribution of each signal to and from the PC board sockets and the cable connectors on the A62 Motherboard assembly, and identifies the signal source.

  • Page 12: 8340A Overall Instrument Theory

    INTRODUCTION Refer to Figure 8A-2, HP 8340A Block Diagram. The HP Model 8340A is a synthesized sweeper that covers the frequency range from 10 MHz to 26.5 GHz in fi v e bands. These bands are: Band 0 (10 MHz to 2.3 GHz) •...
  • Page 13 The Controller Section performs all of the data transfer and coordinates the control signals that operate the HP 8340A. It contains a 16 bit microprocessor, a total of 34K x 16 ROM and SK x 16 RAM. This section also contains interface circuitry for communicating with the rest of the instrument.
  • Page 14 The Band 0 Pulse Modulator, located just before the Band 0 Mixer, is used when the HP 8340A is operating below 2.3 GHz. Operation above 2.3 GHz uses the Band 1-4 Pulse Modulator inside the Mod/Splitter.
  • Page 15 ���� DJSPLAVS DISPLAYS DB0-15 AOR0-4 -5. 2V MOTHERBOARD SUPPLY ( A61) FREE ENCODER -40V BUFFERS UN REG DISPLA'f' µPROCESSOR " -t5V I ::ER��CE SUPPL Y POWER KEYBOARD SNITCH Figure 8A-2. Model 8340A Block Diagram Scans by HB9HCA and HB9FSX 8-13/8-14...

  • Page 16: Calibration Constants

    Default Data differs from the Working and Protected Data: in that its calibration data is the average calibration data of several HP 8340As. This is done to ensure that if any HP 8340A goes to Default Data, it will still be fairly close to its required calibration data for normal operation.
  • Page 17 Model 8340A Service INSTRUMENT PRESET CALIBRATION CONSTANT VERIFICATION SEQUENCE CALIBRATION CONSTANTS DATA CHECKSUM 96 l97 l9a l99 I WORKING (RAM) .,.. 9 6 I 9 7 I 9 a I 9 9 I _____ PROTECTED (EE-PROM) _____ 96 l97 l9a l99 I...
  • Page 18 Immediately after entering the final [Hz], a Cal Constant number and value for that specific Cal Constant will be displayed on the HP 8340A ENTRY DISPLAY.Using the up and down [STEP] keys allows the rest of the Cal Constants to be viewed.
  • Page 19 DWELL TIME represents the number of milliseconds that the HP 8340A will wait, after phase lock at the beginning of a sweep or at bandcross, before it will continue its sweep. Another example is the 9GZ SLOPE. For each count, a power compensation of 0.0025 dB/GHz will be added to the RF output.
  • Page 20 DWELL (#58), A TTEN CONFIG (#59), and CONFIGURATION (#60) use their bit configura­ tion to store more than one piece of information for the HP 8340A. For example, the HPIB ADDRESS sets up the HP 8340A's HP-IB address and allows or disallows the [SHIFT] functions.
  • Page 21 9557 ================================================ ================================================ Procedure for manually entering calibration data into the HP 8340A: Push the following sequence of KEYS: Instrument Preset SHIFT MHz 1 2 Hz SHIFT KHz 2 2 Hz Note the Entry Display will indicate the Calibration Constant number and value.
  • Page 22 Model 8340A Service Table BA-3. Calibration Constants (1 of 7) Range Significance Function Name (Counts) 0-500 0.2 ms/count DWELL TIME Defi n es time to wait after phase lock at beginning of sweep and at bandcross. 0-131 2.4 MHz/ms/count YTMBXDLY2 ·Compensates for YTM Delay in Band 2...
  • Page 23 Model 8340A Service Table BA-3. Calibration Constants (2 of 7) Range Significance Name Function (Counts) Offset compensation for RF power at 20 -200- 0.05 dB/count AT200FFSET dB attenuator setting from 0.01 to 26.5 +200 GHz. Offset compensation for RF power at 30 -200- 0.05 dB/count...
  • Page 24 Model 8340A Service Table 8A-3. Calibration Constants (3 of 7) Range Significance Name Function (Counts) -255 - 0.005 dB/GHz/count AT60 SLOPE Slope compensation for RF power at 60 +255 dB attenuator setting from 2.3 to 20.0 .GHz. Slope compensation for RF power at 70 -255 - 0.005 dB/GHz/count...

  • Page 25: Calibration Constants

    Disabled/Enabled installed) HBIB ADDRESS Selects instrument's operating conditions . I nstrument's :Bits 0 through 4 - selects HP -IB address. 00 - 30 HP -IB Address Bit 5 - allows or disallows the HP-IB 0/32 Allowed/Disallowed address to be changed after entering a...
  • Page 26 Model 8340A - Service Calibration Constants (5 of 7) Table 8A-3. Range Function Significance Name (Counts) Required for Integra Filter operation. 0-20 10 ms/count RETRACE DWELL Selects Attenuator operating conditions. ATTEN CONFIG 0.05 dB/5 counts Bits 0 through 9 - selects attenuator 0-1020 switch threshold.
  • Page 27 UNUSED BKPGAIN YTMTC UNUSED BKPFREQ 0 - 2 0=8340A OI M ODEL Specifies instrument model number 1 =8341A outputted when HP -IB "OI" command 2=8340A-H02 received. UNUSED -32,768 - LOCK WORD Defines password required to access calibration constants. +32,767 8-26...
  • Page 28 Model 8340A - Service Table BA-3. Calibration Constants (7 of 7) Range Significance Name Function (Counts) Disabled/ LOCK WORD Enables lockword function which is 0/-23,875 Enabled ENABLE used to allow access to calibration constants only upon input of the correct password (lockword).

  • Page 29: Troubleshooting Aids

    A53DS3 - - lOV A56DS1 - -15V Three red LEDS indicate when voltage is present on the A l 9 Capacitor Assembly, when the HP 8340A is in shutdown due to over temperature, and when the AC mains is connected. The LEDS are lit when the respective condition exists.
  • Page 30 DIRECT 1/0 ADDRESSING Introduction Direct I/0 Addressing is a tool that allows the user to directly access HP 8340A input and output devices from the front panel. It allows the user to exercise these devices and thus verify their operation.
  • Page 31 Model 8340A Service Table BA-4. (1of3) Devices Direct 1/0 Strobe From Destination Mnemonic Capability Chn- Subchn Type A42U14 Output LCK2 A59U26 LCK3 A59U26 A43U9 Output A43U12 Output LCKl A59U26 A42U12 Output A42U13 Output LCK4 A59U26 A36U5 Output A37U9 Output A37Ul0...
  • Page 32 Model 8340A -.Service Table BA-4. Devices (2 of 3) From Direct 1/0 Strobe Destination Mnemonic Type Capability Subchn RESET PWR A59U12 A59U4 F AILFF Output WCDAC A59U12 A54U16 A6U15 See A6 LEN 4 A6U16 Service LENS A6U15 A6U6 See A6...
  • Page 33 Model 8340A Service Table BA-4. Devices (3 of 3) Destination Direct 1/0 Strobe From Mnemonic Subchn Type Capability WRITE ADR 3 A57Ul Output A57U28 A57U10 Output TRIGGER SEL A57U28 A57U18 Output WRITE STROBE A57U28 A57U25 Output MAN DAC A57U28 A57U9...
  • Page 34 The equipment that is required for strobe verifi c ation is a logic probe. The procedure is as follows: With the HP 8340A switched to ST ANDRY:, place the appropriate assembly on an extender board. Switch the HP 8340A ON and connect the logic probe to 5V and ground.
  • Page 35 Model 8340A - Service Using a logic probe or DVM, probe the output pins of the device being tested. Verify that the output pins are set as shown in Table 8A-5b. [-] [2] [1] [8] [ 4] [6] [ H z].
  • Page 36 I/O Read is performed to verify that the latch is operating. The procedure is as follows: Verify the operation of the input latch's I/O Strobe as described in the strobe verification procedure. Switch the HP 8340A to STANDBY. 8-35 Scans by HB9HCA and HB9FSX...
  • Page 37 Bus. The second number is the decimal equivalent. Using the octal number, verify that the latch is operating correctly (see Example below). 11. Switch the HP 8340A to STANDBY. Reverse the + 5V and ground connections on the input to the device being tested.
  • Page 38 Model 8340A - Service Going from left to right, the first three octal digits are determined by bit numbers 9 through 15. The fourth octal digit is determined by bits 6 through 8 and since bits 6 and 7 are "don't care"...

  • Page 39: Front Panel Diagnostic

    --------- Model 8340A - Service FRONT PANEL DIAGNOSTIC FUNCTIONS The HP 8340A has several self-checking diagnostic routines that can be activated by pressing keys on the front panel. These diagnostics are summaryized in the following text. To Test Front Panel...
  • Page 40 Press [SHIFT] [INT] again and the HP 8340A will sweep to the next band crossing point and stop at that point. Continue pressing [SHIFT] [INT] to single-step through each of the bands. Press...
  • Page 41 (where X.XX is the last-entered value). To set the power level, place the HP 8340A in CW mode, or in pulse modulation mode with pulses wider than 2 usec, and use the keys, the RPG, or the data entry keypad with the [STEP] terminator key to enter the power level desired.

  • Page 42: Overall Instrument Troubleshooting

    This section contains information that is critical to the timely repair of the HP 8340A. when a failure occurs on the HP 8340A, it is important to fi r st verify that the Calibration Constants in memory are good. Refer to the fi r st page of this Service Introduction for details.
  • Page 43 Model 8340A - Service OVERALL INSTRUMENT TROUBLESHOOTING THE FOLLOWING DIAGRAM INDICATES THE PROPER SEQUENCE TO FOLLOW TO ISOLATE SPECIFIC SYMPTOMS.EACH OF THESE IS DESCRIBED IN DETAIL IN THE FOLLOWING PAGES.SEVERAL CATAGORIES MAKE REFERENCES TO THE FRONT AND REAR PANEL ITEMS SHOWN IN FIGURE BA-10 ON...
  • Page 44 Model 8340A - Service FRONT PANEL @@1s@@ REAR PANEL Figure 8A-10. Front and Rear Panel Items 8-43 Scans by HB9HCA and HB9FSX...
  • Page 45 If the rear panel INT/EXT REFERENCE switch is in the EXT position, then the EXT REF annunciator on the ENTRY DISPLAY will be on. b. By changing calibration constant #56 on the HP 8340A can be set to come up with various output power levels after an [INSTR PRESET]. Refer to Calibration Constants in Section VIII for more detailed information.
  • Page 46 Model 8340A - Service CHECK LED I AND II. The two front panel INSTR CHECK LED's are used to indicate the results of the instrument Self-Test. A Self-Test is initiated every time the POWER switch is cycled ON or [INSTR is pressed.
  • Page 47 (A27 Level Control board) Theory of Operation and Troubleshooting. PEAK - This refers to an HP 8340A function that peaks the RF output power at one frequency by fi n e tuning the SYTM (Tunes the SYTM to the YO frequency). This fault can only come on if the button is pushed.
  • Page 48 The S RQ (Service ReQuest) light should be on only during remote operation and when the instrument processor sets S RQ (to the processor) true. Refer to Section IV, HP-IB Operation and Verifi c ation Program to read the HP 8340A Status Bytes.
  • Page 49 Model 8340A - Service The SRQ LED is located on the A2 Display Driver board (Block E). These LED's are driven by the A3 Display Processor, Annunciator Latch/Driver. The LED is turned on by the instrument processor. The processor outputs the appropriate bits on the Data Bus and then outputs address 15:R3 to latch the data bits.
  • Page 50 (Remove the top cover - see pocket along lef t side rail). Check the calibration constants in HP 8340A memory against the hardcopy values. Restore the correct values if necessary. Refer to Section VIII Calibration Constants for more informa­...
  • Page 51 M/N Loop as described in step I above. If the HP 8340A continues to fail the phase noise test, the problem is in the M/N or YO Loop. An external source could be used to replace the M/N input to the YO Loop, but the phase noise of the external source would have to be much better than the HP 8340A phase noise to eliminate the YO Loop.
  • Page 52 A2 9U l (The amplifi e r limiter on the Reference Phase Detector board). SQUEGGING (Band 1-4 only) Observe the spurious response on a spectrum analyzer while changing the HP 8340A output power level. If the frequency of the spur changes with power level, suspect squegging. Refer...
  • Page 53 Model 8340A - Service The key is to treat the spurs as FAMILIES of spurs. A spur family is characterized by having the same mixing path through the instrument. For example, if it can be determined that the 5th harmonic of the M/N VCO is mixing with the 9th harmonic of the 20/30 output, then the location of the spur can be predicted as the 20/30 frequency is changed.
  • Page 54 Theory of Operation and Troubleshooting. REMOTE OPERATION Section IV contains an HP 8340A HP-IB Operation Verifi c ation Programming Listing. This program will verify the ability of the HP 8340A to respond to a remote input (complete HP­ IB handshake). 8-53...
  • Page 55 If the HP 8340A exhibits a problem while running this test, refer to the A60 Processor Troubleshooting in the Controller functional group. If a problem is not observed while running this program and the HP 8340A does not respond properly to other remote commands, refer to the computer documentation to read the computer HP-IB I/O card status.

  • Page 56: Repair Procedures

    Be sure to properly apply ther­ mal compound (HP Part Number 6040-0454 COO) when installing or replacing any of these parts. Refer to the POWER SUPPLY - FAN functional group for thermal compound application procedure.

  • Page 57: Module Exchange Program

    Mix one part deionized water with two parts isopropyl alcohol. Apply this solution to a clean, lint free, cloth (HP Part Number 9310-0039 CD3). Rub the fi n gers carefully and then dry with a clean part of the cloth.
  • Page 58 Seal box with tape. Inside U.S.A.*, stick preprinted return address label over label already on box, and return box to HP. Outside U.S.A., do not use address label: instead address box to the nearest HP office. *HP pays postage on boxes mailed in U.S.A.

  • Page 59: After Service Safety Checks

    The air filter (HP Part Number 08340-00018 for pkg of 10), attached to the cooling fan assembly (rear panel), will require periodic replacement. Due to the variety of environmental conditions, the interval between replacement cannot be estimated.

  • Page 60: Basic Component Symbology

    Model 8340A - Service BASIC COMPONENT SYMBOLOGY © Resistance is in ohms, FET: Field Effect Tran- Pin Edge Connector R, L, C =::: ::r- inductance is in micro- output of PC board. sistor ( N-channel). henries, capacitance is ® in microfarads, unless...
  • Page 61 Model. 8340A Service LOGIC SYMBOLOGY �) AND Gate NOR Gate Inverter Negation symbol. Line is R Gate Exclusive R Gate active low. -[>- NAN D Gate Buffer Amp I ifier Indicated edge-sensitive input. Wired OR FUNCTION LABEL ABBREVIATIONS Adder �...
  • Page 62 REFERENCE GUIDE TO SERVICE DOCUMENTATION Description Bottom View Alpha Display Display Driver Display Processor Not Assigned Keyboard @)@) Keyboard Interface -©- Lower Keyboard 3} GHz Oscillator Band Pulse Modulator Directional coupler Band 1·4 Detector Band Sp!ifterliletector ® SYTM (Switched VIG Tuned Multiplier) •...
  • Page 63 M/N LOOP REFERENCE LOOP INTRODUCTION List of Assemblies Covered THEORY OF OPERATION M/N and Reference Loops - Overall Description M/N and Reference Loops - Simplified Block Diagram TROUBLESHOOTING TO ASSEMBLY LEVEL M/N and Reference Loops - Troubleshooting Block Diagram REPAIR PROCEDURES INDIVIDUAL ASSEMBLY SERVICE SECTIONS A29 Reference Phase Detector A30 1 00 MHz VCXO...
  • Page 64 Model 8340A - Service REFERENCE LOOP - M/N LOOP INTRODUCTION This section provides infor mation and instruction for troubleshooting, rep�iring, or replacing assemblies and components in the Reference Loop and the M/N Loop. Infor mation includes circuit descriptions, troubleshooting procedures,...
  • Page 65 10 MHz source connected to the EXT REF BNC connector on the rear panel. The frequency stability of the 8340A is directly related to the stability of this 10 MHz signal. The Reference Loop consists of two assemblies:...
  • Page 66 Model 8340A - Service M/N LOOP DESCRIPTION The M/N Loop generates the 177-197 MHz signal that drives the A48 Sampler in the YO Loop. Harmonics of the M/N signal are generated in the Sampler and are used to down convert the 2.3-7.0 GHz YO output to the 20-30 MHz range so that the YO can be phase locked to the output of the 20-30 Loop.
  • Page 67 Model 8340A - Service MHz, and for every increment in number, the output will increase 200 MHz. This relatioriship is given in the following equation where f is the output of the 2 0 to 30 Loop: 2 0,30 200*N...
  • Page 68 ---------- ------------------ - - - -1 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - I A33 M/N OUTPUT A29 REFERENCE IOavlHZ IOOMHz...
  • Page 69 Model 8340A - service REFERENCE LOOP - M/N LOOP TROUBLESHOOTING TO ASSEMBLY LEVEL REFERENCE UNLOCK TROUBLESHOOTING First check that the INT/EXT switch on the rear panel is in "INT" position. Check that a jumper cable is connected between rear panel connectors "INT"...
  • Page 70 (NOTE: When measuring the M/N frequency, it is advisable to have the 8340A and the measuring device, ie. counter or spectrum analyzer, both'locked to the same 10 MHz standard.) If the measured frequency and the frequency in the first window...
  • Page 71 Model 8340A - Service and some do not, then the problem is most likely on the M Divider portion of the A31 M/N Phase Detector board. Press This sets the 8340A to [SHIFT] [CF] [MHz] [CW] • step the CW frequency in 200 MHz increments. For each 200 MHz step, the "N"...
  • Page 72 Model 8340A - Service 8-95/8-96 INSERT IN FRONT OF PAGE A51 10 O_A ! 2 MOTH �f!E � s ; A 3 5P HB, 36 ;�� v T O ClACUIT A69P1-10 µ_ HOVC TO >--J- - GND (CASE GROUND) REF O SC A62Pl-20 .J3 1...
  • Page 73 A51 IOMHZ NOTES: REFERENCE P/O A62 MOTHERBOARD I, REFER TO FIGURE8A-12FOR A 8340A DESCRIPTION OF THE SYMBOLOGY USED REAR ON THIS BLOCK DIAGRAM. PANEL COARSE J3 +20 REF o : c-1 � A51W I Pl 2. NOT ALL POWER SUPPLY INTERCONNECTIONS...
  • Page 74 Model 8340A - service REPAIR PROCEDURES Refer to the REPAIR PROCEDURES description in the beginning of Section VIII. 8-97/8-98 Scans by HB9HCA and HB9FSX...
  • Page 75 Model 8340A - service A29 REFERENCE PHASE DETECTOR INTRODUCTION The A29 Reference Phase Detector contains the frequency divider, phase detector, and integrating amplifier for the 100 MHz Reference phase-locked loop. Basically, 100 MHz f rom the A30 VCXO divided 10 and compared to the 10 MHz frequency standard by the phase detector.
  • Page 76 � Model 8340A - Service Integrating Amplifier Q4 is a differential input pair which together with QS and Q6 forms a high gain amplifier. Feedback is added with C32 and R49 to make an integrating amplifier. C32 provides ac feedback only,...
  • Page 77 Model 8340A - Service MP4, 1DOMHZ 1 OMHZ 10MHZ BOTTOM SIDE 20MHZ OUT 10MHZ OUT A-2233-4S Reference Phase Detector, Component Location Diagram Figure 8B-3. 8-101/8-102 Scans by HB9HCA and HB9FSX...
  • Page 78 Reference Phase Detector Pin 1/0 Destination Mnemonic Levels Source -10V -10V XA34P2-8, 9 -40V -40V XA34P2-6, 7 INSTRUMENT GROUND . *K INSTRUMENT GROUND +20V +20V XA34P2-2, 3 INSTRUMENT GROUND HULR HIGH TRUE XA34P2-14 INSTRUMENT GROUND -5.2V -5.2V XA34P2-12, 13 INSTRUMENT GROUND INSTRUMENT GROUND XA30P1-12 TUNE GROUND...
  • Page 79 TPI. NOTES: I. REFER TO THE SERVICE SECTION INTRODU CTION FDR DETAILED SCHEMATIC REFERENCE DETECTOR +61'R DIAGRAM SYMBOLOGY NOTES. � 2, RESISTANCE VAL�S Sl-l O WN ARE IN LIMITING AMPLIFIER ® PULSE GENERATOR BUFFER PHASE LOCI( SAMPLER INTEGRATING AMPLIFIER OH�s. CAPACITANCE MICROFAR�DS, AMPLIFIER AND INDUCTANCE lN MlCRDHENRIES...
  • Page 80 Model a340A - Service A30 100 MHz VOLTAGE-CONTROLLED CRYSTAL OSCILLATOR (VCXO) INTRODUCTION The A30 100 MHz VCXO contains a voltage Controlled Crystal Oscillator, a 100 MHz Buffer Amplifier, a frequency Quadrupler, and a 400 MHz Amplifier. With the A29 Reference Phase Detector, forms the Reference Phase-Locked Loop.
  • Page 81 Model B340A - Service Rll, R54, and Ll determine the bias and gain of Q5. TP3 should be at approximately -14.B Vdc for correct bias. 100 MHz Buffer Amplifier Transistors Q9 and QB function as buff er amplifiers to isolate the vcxo from variations in load which would otherwise cause frequency pulling of the oscillator.
  • Page 82 Model 8340A - Service undesired harmonics of 100 MHz. The output of Ql is passed through a pad comprised of R67, R68, and R69. The nominal attenuation of the pad is 5 dB, however the actual attenuation is selected to set the 400 MHz OUT signal level to -10 dBm +l dB.
  • Page 83 Model 8340A - Service A30 100 MHz VOLTAGE-CONTROLLED CRYSTAL OSCILLATOR TROUBLESHOOTING 100 MHz Oscillator A REFERENCE UNLOCK The output of the 100 MHz VCXO should be phaselocked at 100 MHz. When troubleshooting the VCXO for a REFERENCE UNLOCK, first disconnect the cable at A30Jl, the 100 MHz OUT signal to the A29 Reference Phase Detector.
  • Page 84 Scans by HB9HCA and HB9FSX...

  • Page 85: And 400 Mhz Amplifier

    Model 8340A - Service The 100 MHz OUT signal at Jl and J2 and the 400 MHz OUT signal are set to the correct power level by resistive pads (R30, R31, R32; R33, R34, and R35; and R67, R68, and R69). The attenuation of these pads is selected to give the required power.
  • Page 86 Scans by HB9HCA and HB9FSX...
  • Page 87 Model 8340A Service 1 OOMHZ 1 OOMHZ 100MHZ 400MHZ 400MHZ 1 OOMHZ MP15 TUNE C56 MP14 400MHZ OUT MP13 MP3, MP10 MP11 MP16 CSHIELO,ON BAC:KSIOE) MP12 PLACES Figure 8B-5. A30 100 MHz VCXO, Component Location Diagram 8-115/8-116 Scans by HB9HCA and HB9FSX...
  • Page 88 A30 100 MHz VCXO Pin Levels Source Destination Mnemonic -10V -10V XA34P2-8, 9 -40V +40V XA34P2-6, 7 +20V +20V XA34P2-2, 3 INSTRUMENT GROUND INSTRUMENT GROUND INSTRUMENT GROUND INSTRUMENT GROUND INSTRUMENT GROUND INSTRUMENT GROUND TUNE GROUND XA29P1-12 TUNE VOLTAGE XA29P1-13 INSTRUMENT GROUND A single letter in the source or destination column refers to a function block on this assembly schematic.
  • Page 89 • • • · NOTES: H . z . ·· . · . · ..· •. I, REFER TO THE SERVIC E SECTION INTRODU CTION FOR DETAILED SCHEMATIC DIAGRAM SY�BOLOGY NOTES, 2, RESISTANCE VALUES � 100 MHZ BUFFER/AMPLJFJER SHOWN ARE IN OHMS•...
  • Page 90 Model 8340A - Service A31 M/N PHASE DETECTOR INTRODUCTION The M/N phase detector has two programmable frequency dividers: M divider and an N divider. M and N are integer numbers which give the ratio of divider input frequency to divider output frequency (i.e.
  • Page 91 Model 8340A - Service M Divider Output PRF (MHz) N Divide Number M Divide Number M Divider Clock frequency (MHz) 20 MHz N Divider Clock frequency when the loop is phase locke _ d ; Therefore, (4/N) (20 MHz) (4/M) (f...

  • Page 92: 5. Divider Operations

    Model 8340A - Service the N numb�r (0100) are loaded into U6 (a programmable counter). Clock 2 subtracts 4 (0001) from the previous total leaving (0011); Clock 3 subtracts 4 more and the 0010 output enables the End of Count Decoder.
  • Page 93 Model 8340A - Service Mixer Q3 is an amplifier that drives the LO port of mixer U24. supplies about +5 dBm over the 355 to 395 MHz range. The output of the mixer is the difference between 400 MHz and the M/N vco frequency which gives an IF frequency between 5 and 45 MHz.
  • Page 94 Model 8340A Service N CLOCK PULSES 20 MHz µ.s 1-...i 0.05 INPUT N-DIVIDER OUTPUT i..-t -...-j 0. 2 µ.s (5 MHz) M CLOCK PULSES IF INPUT : I I i.- o.o4 µ.s -...i (25MHz) I II I IJ M-DIVIDER OUTPUT �...
  • Page 95 Model 8340A - Service Table 8B-5. Divider Operations N number Input End of Flip-Flop Clock Operation in Counter Count Count Output Pulses Decoder Control (4 MSB) Load Counter 0100 Inactive Reset Reset Minus 4 0011 Inactive Reset Reset 1. 4...

  • Page 96: Increment Decoder Operation

    Model 8340A - Service Table 8B-6. Increment Decoder Operation Increment Decoder Increment Decoder Output Sequence* Control Inputs L ( O) L ( O) H ( 1) L ( O) H ( 1) L ( O) H ( 1) H ( 1)
  • Page 97 Model 8340A Service MP1'1 MP15 MP2B MP57 MP27 MP61 MP53 MP5B MP5'1 355-395MHZ MP60 MP35 MP56 MP36 '100 MHZ MP65 MP55 HP63 MP13 MP28 MP59 MP31f MP62 HPS-12 HP16-25 MP'll!-52 TYPICAL 10 PLACES MP2S-33 TYPICAL 5 PLACES •• TP'I @[::: :I •...
  • Page 98 Phase Detector Pin Source Destination Mnemonic Levels -1aV -10V XA34P2-8, 9 -1aV -10V XA34P2-8, 9 +20V +2aV XA34P2-2, 3 +2aV XA34P2-2, 3 +2aV -5.2V -5.2V XA34P2-12, 13 -5.2V -5.2V XA34P2-12, 13 INSTRUMENT GROUND INSTRUMENT GROUND INSTRUMENT GROUND INSTRUMENT GROUND vco TUNE vco TUNE INSTRUMENT GROUND INSTRUMENT GROUND...
  • Page 99 • "' • •• • • TP:S TPl5 REFER TO 08340-60036 THE SERVICE SECTION M/N PHASE DETECTOR INTRODUCTION FOR DETAILED SCHEMATIC OIAGRAM SYMBOLOGY NOTES. LEVEL TRANSLATORS N DIVIDER PHASE/FREQUENCY D�TECTOR RES!STANCE VALUES ARE IN OHMS , CAPACITANCE IN Ul28 +20VF >...
  • Page 100 Model 8340A - Service A32 M/N VOLTAGE-CONTROLLED OSCILLATOR INTRODUCTION The M/N vco (voltage-controlled oscillator) is a varactor-tuned cavity oscillator. It consists of a fore-shortened coaxial cavity resonator, a transistor circuit, and both a mechanical and an electrical tuning mechanism. Refer to Figure 8B-13,...
  • Page 101 Model 8340A - Service Rl3 and Cll are part of the feedback network that determines the frequency response of the M/N Phase Locked Loop. (See also the M/N Loop Frequency Response section in the A31 M/N Phase Detector circuit description.)
  • Page 102 Model 8340A Service CFAR SIDE) Figure 8B-l l. MIN VCO, Component Location Diagram 8-137 /8-138 Scans by HB9HCA and HB9FSX...
  • Page 103 Model 8340A - Service M/N OUTPUT INTRODUCTION The A33 M/N Output board amplifies the output of the A32A2 M/N VCO in two different paths. One path contains amplification and buffering to drive the mixer in the A31 M/N Phase Detector.
  • Page 104 0 dBm signal. Divide-By-2 U2 is an EECL (HP ECL) divider used to generate the M/N output signal which is at one-half the frequency of the M/N vco. LMNE (Low M/N Enable) is an M/N Loop control line that could be used to turn on and off the divider through the operation of the TTL-ECL Level Shifter.
  • Page 105 Model 8340A - Service S55-ll95 MH:Z OUT MP26 MP2ll M/N OUT MPS-MP12 MPB.MP17 MP1B.MP19 MP2lf.MP25 CTYPICAL C2ll 2 PLACES) ASll OUTPUT MP20 S55-ll95 MH:Z o oeM Output Assembly, Component Location Diagram Figure 8B-12. 8-141/8-142 Scans by HB9HCA and HB9FSX...
  • Page 106 Output Pin Mnemonic Levels Source Destination VCO TUNE(+) XA31 P1-21 INSTRUMENT GROUND VCO TUNE(-) XA31 P1-6 INSTRUMENT GROUND -10V -10V XA34P2-8, INSTRUMENT GROUND -5.2V -5.2V XA34P2-12, 13 INSTRUMENT GROUND INSTRUMENT GROUND INSTRUMENT GROUND XA34P2-6, -4aV -4aV INSTRUMENT GROUND L M NE (L O W TRUE) INSTRUMENT GROUND A single letter in the source or destination column refers to a function block on this...
  • Page 107 <e • · A32 M/N l/OLTAGE -caNTROLLECi osc I LLATOR (I/CO) ASSEIYBL y NOTES: 08340-6009 l REFER T O THE SERVICE SECTION LOOP A MPLIFIER (MOTE 6) INTRODUCTION FOR DETAILED SCHEMATIC DIAGRAM SYMflOLOGY NOTES. 2. RESISTANCE VALUES ARE IN OHMS, A32Al M/N VCO OARD I"'...
  • Page 108 A34 M/N - REFERENCE MOTHERBOARD A34 M/N - REFERENCE MOTHERBOARD (Bottom View) (Top View) MP2 (WASHER) MP3 (NUT) (EACH, 2 PLACES: (14 PLACES) Cl3, Cl4) XA34P2 XA33 08340-60039 A-2231-45 M/N OUT MPl5 08340-60039 ® A-2231-45 - ----- XA30 - ----- MPl7 XA30 100 MHz VCXO...
  • Page 109 Model 8340A Service Reference - MIN Motherboard Pl Pin IIO Mnemonic Levels Source Destination !HIGH TRUE) XA59P1-31 XA31P1-15 LMNE TTL jLDW TRUE) XA59P1 -86 jHIGH TRUE) XA59P1-32 XA31 Pl-14 !HIGH TRUE) XA59P1-B7 XA31 Pl-29 !HIGH TRUE) XA59P1 -33 XA31 Pl-13...
  • Page 110 NOTES: A34 M/N REFERENCE MOTHERBOARD THE SERVICE SECTION 08340-6000 REFER TO IN TRODUCTIOI� FOR DETAILED S CHEMATIC DIAGRA M SYMBOLOG Y N O TES, 2. RES I S TANCE VALU ES SHOWN ARE IN OHMS, CAPACITANCE IN MICRO FAR ADS, AN D IN DUCTANCE IN MICROHEN R IES UNLESS OTHERWlSE NOTED.
  • Page 111 Model 8340A Service REFERENCE OSCILLATOR A51 10 MHz "COARSE" and" Fl NE" Frequency Adjustments SIDE VIEW Cable Tie SIGNAL Not Shown A51 W1 P1 +22V OVEN HOVC GND (CASE GND) OSCILLATOR A51W1 BOTTOM VIEW A51J1 A51 JO MHz Reference Oscillator, Component Location Diagram Figure 8B-16.
  • Page 112 Model 8340A Service A62J3 A51 WIPI Pin A62J3 Levels Mnemonic A51W1 P1 PIN 1 OV/+20V +20V REF DSC PIN 2 PIN 3 +3V/DVEN WARM HOVC PIN 4 +22V PIN 5 +22V Note: Refer to M/N and Reference Loops Troubleshooting Block Diagram and A62 Motherboard Wiring List for signal source and destination information.
  • Page 113 Scans by HB9HCA and HB9FSX...
  • Page 114 REFERENCE GUIDE TO SERVICE DOCUMENTATION Description Bottom View · .- • � > ; - . · ·· _ 34 � 1 .• . · .. . ; _;8.Md ;,•; . '"· ;; ® SYTM (Switched YIG Tuned Multiplier) Band 1-4 Power Amplifier A 15 Band Low Pass Filter...
  • Page 115 20-30 LOOPS INTRODUCTION List of Assemblies Covered THEORY OF OPERATION 20-30 Loop - Overall Description 20-30 Loop - Simplified Block Diagram PLL2 Loop Description PLL3 Loop Description PLL 1 Loop Description TROUBLESHOOTING TO ASSEMBLY LEVEL 20-30 Loop - Troubleshooting Block Diagram REPAIR PROCEDURES INDIVIDUAL ASSEMBLY SERVICE SECTIONS A36 PLL1 VCO...
  • Page 116 Model 8340A - Service 20-30 LOOP INTRODUCTION This functional group contains the following information: Overall description of the 20-30 Loop. � Simplified Block Diagram. � Overall descriptions of individual PLL2, PLL3, and PLLl Loops. � Troubleshooting Block Diagram. � Circuit Descriptions, Component Location Diagrams, Pin I/O �...
  • Page 117 A40 PLL2 VCO A41 PLL2 PHASE DETECTOR A42 PLL2 DIVIDER A43 PLL2 DISCRIMINATOR DESCRIPTION The 20-30 Loop provides the 8340A with 1 Hz CW (YO) tuning resolution. In swept frequency modes the 20-30 Loop provides high resolution tuning in sweep widths from 100 Hz to 5 MHz.
  • Page 118 Model 8340A - Service CONFIGURATION 1 This configuration is used in sweep widths from 5 MHz to >100 kHz. PLL2 phase-locks a 75 to 150 MHz to a 10 MHz reference frequency derived from the Reference Loop. The PLL2 programmable in 5 kHz steps, and it can be swept a maximum of 25 MHz using a lock and roll analog sweep.
  • Page 119 Model 8340A - Service Loops are used to translate the high resolution, low frequency PLL2 output up to a 200 to 300 MHz range. Since a translation is a fixed offset in frequency, it will not change the resolution as does dividing or multiplying.
  • Page 120 Model 8340A Service Table 8C-l. 20-30 Loop Parameters 8340 SWEEP Loops Used: PLL2 VCO Divide Total 20-30 WIDTH divided output by 10 divide -------------- (YO) PLLl PLL2 PLL3 {PLLl) number resolu- tion 5 MHz 1 kHz >100 kHz 100 kHz 20 Hz >5 kHz...
  • Page 121 Model 8340A - Service 8-165/8-166 INSERT IN FRONT OF PAGE PLL2 VCO 60-300kHz STEPS IOHz 3-eMHz 200Hz STEPS 76-160MHz - - - - - - - - - - - - - _j SEE ADJACENT TABLE ___ _ _ P/O Figure 8C-l.
  • Page 122 ,;oMHz, BAND I In X I) PLLI DIVIDER PLLI VCO !5kHz TO I OOkHz 61': 5MHz TO >. IMH:z OOl<Hz TO >51<HZ AND CW MODE OMHz Od8m FROM A29 REF STEP SlZE' I kHz 20Hz PHASE DF.TECTOR OUT OF 20-30MHz SWITCH POSIT ION: 3 .
  • Page 123 - · - � · - · ·--·-- · · - - - - · · ··-· · ---··-··· ·-· Model 8340A - Service PLL2 OVERALL DESCRIPTION INTRODUCTION PLL2 (Phase Lock Loop 2) is part of the 20-30 Loop Synthesizer.
  • Page 124 Model 8340A - Service DISCRIMINATOR ;_::: : Four Figure 8C-2. PLI..2 Discriminator Feedback The phase lock loop path is closed during the pre-sweep interval in swept modes, .and is closed at all times in CW mode of operation. While the loop is locked,...
  • Page 125 Model 8340A Service CMHz FROM > ' 20 REFERENCE LOOP ------ SAMPLE· ANO··l IOLO FRACTIONAL DIV IDER �---------' TUNE VOLTAGE ,-------------------- .. - ---- ----, FREQ-TO-CURRENT RATIO) (CllANGES D lSCRIMINA TOR : � } �54 • 20 PRET1JNE _ _ __ �...
  • Page 126 Model 8340A - Service COUNTER DOWN PHASE-ERROR VOLTAGE FROM PHASE/FREQUENCY DETECTOR DISCRIMINATOR TUNE SAMPLE-AND-HOLD CONTROL ANALOG INTEGRATOR Figure 8C-4. PLI.2 Simplified Sample and Hold Circuit 8-170 Scans by HB9HCA and HB9FSX...

  • Page 127: Divider Conf I G Uration

    Model 8340A - Service approximately± one of the two comparators will turn on its associated clock. The clock will either increment or decrement counter which will increase or decrease the current out of the DAC. The DAC output will further correct the tuning voltage for the...
  • Page 128 Model 8340A - Service PLL3 OVERALL DESCRIPTION The PLL3 (Phase Lock Loop 3) is part of the 20-30 Loop Synthesizer. It consists of only the A39 Upconverter Assembly. The PLL3 and PLLl phase-lock loops are only used when in CW Mode or in swept frequency modes with YO sweep widths less than 100 kHz.
  • Page 129 -·····---·-·· ..Model 8340A - Service MIXER The output of the MIXER is amplified, filtered, sent to the PHASE/FREQUENCY DETECTOR. The desired MIXER output is the difference frequency and lies between kHz and 6 Mhz. PHASE/FREQUENCY DETECTOR The PHASE/FREQUENCY DETECTOR generates a differential output signal that is used by the LOOP AMPLIFIER as well as the PHASE LOCK INDICATOR.
  • Page 130 Model 8340A - Service PLLl OVERALL DESCRIPTION INTRODUCTION PLLl (Phase Locked Loop 1) is part of the 20-30 Loop Synthesizer. It consists of the following assemblies: A36 PLL 1 VCO A37 PLLl DIVIDER � A38 PLLl IF DESCRIPTION The PLLl and PLL3 phase-lock loops are only used when in CW Mode or in swept frequency modes with YO sweep widths less than 100 kHz.
  • Page 131 After the final divide-by-ten, the output frequency of the 20-30 loop becomes; Fout (Fpll3)/10 Nl MHz. Fpll3 can be determined from the 8340A diagnostics by pressing [SHIFT] [M3] and reading the right-hand "FREQUENCY MHz" display. If this display reads "0�0000" then the PLL3/PLL1 path is not being used in this mode, and PLL2 is used by itself.
  • Page 132 �--' Model 8340A Service ,. -----------------, ,.-------------------------------------, «ounur • ?.00 TO 300Lfi• SWITCH! I .:'}MHz F20/30 IOIOi• FRO• A29 RE F ERENCE PHASE OETECTOR F PLL3 GAIN SWlTCHlN<i 3,80-13.97 PLLI PLLI DIVIDER - - .. - - ..- - - - _ ..
  • Page 133 � A37 PLLI DIVIDER J�OLLE D OSC�L _ L A TOR ( VCO) IN IDMH • "" TPID ��g� ®PHASE / NULL "'""' REFERENCE PH HUL I ® ""�" TO A59Pl-IOS DIVIDE INDICATOR >-1-- x:;i A42 PLL2 DIVIDER " ' -- - -- - �F...
  • Page 134 Model Service 8340A TROUBLESHOOTING TO ASSEMBLY LEVEL Ref er to "OVERALL INSTRUMENT TROUBLESHOOTING" in the Service Introduction. 8-181/8-182 Scans by HB9HCA and HB9FSX...
  • Page 135 Model 8340A Service REPAIR PROCEDURES Refer to the "REPAIR PROCEDURESn description in the Service Introduction. 8-183/8-184 Scans by HB9HCA and HB9FSX...
  • Page 136 Model 8340A - Service A36 PHASE LOCK LOOP 1 (PLLl) VOLTAGE-CONTROLLED OSCILLATOR (VCO), CIRCUIT DESCRIPTION DESCRIPTION The output of the 20-30 loop to be fed to the YO Loop is always taken from A36 (PLLl VCO). If the sweep width is such that the...
  • Page 137 Model 8340A - Service The output of the differential integrator is fed through a programmable ac voltage divider formed by R31, R32, R33, R34, R35 with R36 and C36. Following this is a 40kHz low pass filter which has two notches that are tuned to reject 50kHz generated by the fractional division used in PLLl divider.
  • Page 138 Model 8340A - Service 200 to 300 MHz VCO OUTPUT AMPLIFIER · The vco consists of Qll which operates in the grounded-base mode. The resonator is principally CR3, CR4, and L4. Feedback is accomplished with LS, Rl6, and Cl7. The output, taken at Cl4, coupled through R42 and Cl2 to common base buffer amplifier Q5.
  • Page 139 Model 8340A - Service 15-30 MHz input from PLL2 vco to the output. For all other sweep conditions the SWl line is high and the loop is enabled. output is then taken from UlD which has the divided by 10 VCO frequency as its input.
  • Page 140 Model 8340A Service OUT 200-SOOMHZ 15-SOMHZ OUT 20-aoMHZ MP17 .1 -5MHZ MP1-6 MPB-11 MP14-16 CTYPICAL S PLACE MP12 MP1S • Figure BC-JO. PLLJ VCO, Component Location Diagram 8-189/8-190 Scans by HB9HCA and HB9FSX...
  • Page 141 Model 8340A Service PLLJ VCO, Pin I/0 Destination Mnemonic Levels Source A62 STAR GND A62 STAR GND *THRU A62R7 TO B *THRU A62R8 TD B DB1a *THRU A62R9 TO B DB11 *THRU A62R1a TO B *THRU A62R11 TO B LCK4...
  • Page 142 TP I I. REFER TO THE SERVICE SECTION NOTES; • • IN TRODUCTION FOR DETAILED SCHEMATIC DIAGRAM SYMBOLOGY NOTES. LOCK 2. RESISTANCE VALUES SHOWN ARE IN OHMS, A36 PHA$E OP I ( PLLI ) CAPACITi\NCE IN MICROFARAOS, AND VOLTAGE CONTROLLED INDUCTANCE IN MICROHENRIES UNLESS LOOP AMPLIFIER OSCIUATOR...
  • Page 143 Model 8340A - service A37 PHASE LOCK LOOP 1 (PLLl) DIVIDER, CIRCUIT DESCRIPTION INTRODUCTION A37 functions as a programmable frequency divider and a phase/frequency detector. DESCRIPTION The divider is programmed by the A6 0 Processor to divide the input frequency down to 5 MHz. This is then compared with a 5 MHz reference in the phase/frequency detector.
  • Page 144 Model 8340A Service INPUT OUTPUT DISABLE COUNT FOR ONE INPUT PULSE RATE MULTIPLIER � (2 DIGIT BCD) Figure 8C-12. Fractional Division Using Pulse Swallowing 8-196 Scans by HB9HCA and HB9FSX...
  • Page 145 Model 8340A - Service Refer to the "Frequency R ange and CW Mode Accuracy" Performance Test for use as a troubleshooting aid. DIVIDE-BY-2 U5 constitutes a 3-stage limiting amplifier. U5 is an ECL triple line receiver which changes the input to the proper amplitude and...
  • Page 146 Model 8340A Service INPUT CLOCK (TP3J TPS WIRE OR OUTPUT TP6 LNLOAD ASYNCHRONOUS TPl3 DIVIDER OUTPUT COUNTER CONTENTS N-Divider Operation; N 5 (HSWALLOW not used) Figure BC-13. 8-198 Scans by HB9HCA and HB9FSX...
  • Page 147 Model 834 0A - Service in synch with the output pulse (TP13). The low-to-high transition of TP7 will clock Ul5B and leave it in the RESET state. Ul5B pin 15, LOW SWALLOW ENABLE is connected to the reset of Ul4B. As long as LOW SWALLOW ENABLE is HIGH, HSWALLOW will be forced LOW independently of its clock changing.
  • Page 148 Model 8340A Service INPUT CLOCK D INPUT TO REFERENCE HSWALLOW FF WAVEFORMS (TP91 OUTPUT PULSE CTP 13) HSWALLOW <TP5l STATE *I: • RA TE MULTI PLIER DOES OUTPUT A PULSE LOW SWALLOW • LOW SWALLOW ENABLE ENABLE WAS HIGH HSWALL OW <TP5)
  • Page 149 Model 8340A - Service and Cll will delay the HIGH-to-LOW transition at Ul5B pin 10 by several nanoseconds to allow the clock to reach Ul5B before the HIGH on pin 10 input goes away. This leaves Ul5B set, as desired.
  • Page 150 Model 8340A - Service PHASE LOCK INDICATOR The input to the Phase Lock Indicator is the wire OR outputs of the phase/frequency detector (Al6B pin 14 and Al6A pin 3). This input is ECL LOW (approximately 3 volts) when the loop is locked;...
  • Page 151 Model 8340A - Service IN PLL1 ON= PLL1 .lfLOCK MP16 MP12 • filfil� MP13 A-2237-1.fS • � TP'+ • TP11 • • • MP17 TP13 • • U11+ TP12 � i � � B MPLI . a��� TP1ll 000000 000000 000000 ®...
  • Page 152 Model 8340A - Service PLLJ Divider, Pin 1/0 Levels Source Destination Mnemonic XA60P1-20 XA60P1 -76 XA60P1-21 XA60P1-77 XA60P1-22 XA60P1-78 XA60P1-23 XA60P1-79 A62 STAR GNO A62 STAR GNO 0810 0811 XA59P1-52 LCK4 LOW TRUE XA59P1-106 HULi HIGH TRUE A62 STAR GNO...
  • Page 153 • TPIO TPI I 2 r � 2 NOTES REFER ro THE SERVICE SECTION LOCK A37 PHASE LOOP I (PLLI) Oii/IDER INTRODUCTION FOR DETAILED SCllEMATIC OtAGRAM SYMBOLOG NOTES. 08340-60043 2. RESISTANCE �ALUES SHOWN ARE lN OHMS,CAPACITANCE IN MICROFARADS,AND lNDIJCTANCE lN r.llCROflENRIES UNLESS DIVIDE BY N OTHERWISE NOTEO, tVVF...
  • Page 154 Model 8340A - Service A38 PHASE LOCK LOOP (PLLl) IF, CIRCUIT DESCRIPTION INTRODUCTION The function of the A38 Phase Lock.Loop 1 is basically to mix the output of the A39 PLL3 Up Converter (160.15 to 166 MHz) with the LO output from the A36 PLL l VCO (200 to 300 MHz).
  • Page 155 Model 8340A Service JN 200-SOOMHZ JN 160-166MHZ MP21 OUT PLL1 IF MP2-7 MP10-12 MP17-1S CTYPICAL 3 PLACES) MP1 .. � -"\ MP13 � oo cm �� MP15 MP16 :� � 170MHZ NULL �� � -� -� E£E � � 1BBMHZ NULL 000000000000000 A-21 ..
  • Page 156 Model 8340A Service A38 PLLJ IF, Pin Mnemonic Levels Source Des ti nation A62 STAR GND A62 STAR GND A62 STAR GND A62 STAR GND A62 STAR GND A62 STAR GND A62 STAR GND A62 STAR GND A62 STAR GND...
  • Page 157 NOTES: A38 PHASE. LOCK LOOP ( PLLI) 08340-60044 I. REFER TO THE SERVICE SECTION MIXER INTRODUCTION DE TAILED SCHEMAT I C IN 160- I 66MHZ DIAGRAM SYMBOLDGY NOTES, � � ;--- 185MHZ LPF---" ""\. � 2. RESISTANCE VALUES SHOWN ARE l60-l 661.4HZ IN OHMS.CAPACITANCE JN -20dBm...
  • Page 158 Model 8340A - Service A39 PHASE LOCK LOOP 3 (PLL3) UPCONVERTER, CIRCUIT DESCRIPTION INTRODUCTION The function of the A39 Phase Lock Loop 3 Upconverter is to mix 160 MHz with the output of the A40 PLL 2 VCO (.1 5 to 6 MHz) output the sum of the two frequencies.
  • Page 159 Model 8340A - Service The 160 MHz bandpass filter selects the 160 MHz signal that is amplified by Q5. Ll8, C49 and C50 form a tank circuit that is tuned to 160 MHz which also helps to reject unwanted frequency components from the output of U3.
  • Page 160 Model 8 340A - Service The SET inputs to both flip-flops are tied together and are driven by the output of the NOR gate U6A. Whenever the non­ inverted outputs of the flip-flops are both low the SET lines on both flip-flops are asserted and the non-inverted outputs of the flip-flops will both go high.
  • Page 161 Model 8340A - Service Clock Clock Non-inverting Output Non-inverting Output 2 A39 PLL3 Phase/Frequency Detector Waveforms Figure 8C-20. PHASE LOCK INDICATOR The PHASE LOCK INDICATOR senses the outputs of the PHASE DETECTOR to determine when the loop is locked. The non-inverting outputs of the phase detector flip-flops are attenuated by R23 and summed into the inverting input of UlA.
  • Page 162 Model 8340A Service MP22 DN=PLUI 160-16GMHZ liJ LDCK MP12 C41 C42 MP1'1 U<I 160MHZ PEAK 160MHZ PEAK 160MHZ PEAK J<I 0.15-SMHZ -27DBM MP1B MP1-MP5 (5 PLACES) Figure 8C-21. A39 PLL3 Upconverter, Component Location Diagram 8-221/8-222 Scans by HB9HCA and HB9FSX...
  • Page 163 Model 8340A Service A39 PLLJ Upconverter, Pin Destination Mnemonic Levels Source HUL1 XA59P1-1 a6 TTL !HIGH TRUE) HUL1 TTL !HIGH TRUE) XA59P1-106 A62 STAR GND A62 STAR GND A62 STAR GND A62 STAR GND A62 STAR GND A62 STAR GND...
  • Page 164 TP-2-· • • • --- - �--- N OTES PHASE LOCK LOOP UP CONVERTER 3 (PLL3) I. REFER TO THE SERVICE SF.CTION 08340-60045 INTRODUCTION l'OR OETA.IL E D SCHEMATIC DIAGRAM SYMBOLOGY NOTES. 2, RESISTANCE VALUES ARE HI OHMS, CAP�CITMICE IN �...
  • Page 165 Model 8340A - Service A40 PHASE LOCK LOOP 2 (PLL2) VCO, CIRCUIT DESCRIPTION INTRODUCTION The A40 Phase Lock Loop 2 VCO assembly accepts a tuning current f' r om the 'A43 PLL 2 Discriminator board to adjust the VCO frequency between 150 and 75 MHz.
  • Page 166 Model 8340A - service impedance filtered -32V source to bias the VCO varactor tuning diodes. Q5 and Q6, minimize the in a darlington configuration, fluctuations in base drive requirements as the tuning current is varied. Any fluctuations in base current cause a long time-constant change in the -32V output level due to the large resistors and capacitors in the base circuit.
  • Page 167 Model 8340A - Service r-----------, � L4 AND L5 CR I CR 4 LOAD ___________ Figure 8C-23. Equivalent VCO Resonant Circuit 8-229 Scans by HB9HCA and HB9FSX...
  • Page 168 Model 8340A Service 0.16 Simplified Divider Circuit Figure 8C-24. 8-230 Scans by HB9HCA and HB9FSX...
  • Page 169 Model 8340A - Service SMALL DELTA SWITCH US functions as a single-pole double-throw switch, routing either 3 to 6 MHz from U2 or 0.15 to 0.30 MHz from Ul, to the A39 PLL3 Up Converter. The required range is selected by a TTL signal...
  • Page 170 Model 8340A Service 15-SOMHZ 75 TO 150MHZ .15 TO .aoMHZ oM-��� OUT FOR VC:O TUNE IN MP10 AF::;_ .1MHZ MP1 1 1 -5MHZ MP5, MPS • 150MHZ AO.JUST MP1-MP4 (TYPIC:AL 4 PLAC:ES) A-22'82-45 PLLJ VCO, Component Location Diagram Figure 8C-25.
  • Page 171 Model 8340A Service A40 PLL2 VCO, Pin l/0 Destination Mnemonic Levels Source A62 STAR GND A62 STAR GND A62 STAR GND A62 STAR GND A62 STAR GND A62 STAR GND A62 STAR GND A62 STAR GND A62 STAR GND A62 STAR GND...
  • Page 172 NOTES: REFER TO THE SERVICE SECTION INTRODUCTION FOR DETAILED SCHEMATIC DIAGRAM SYMBOLOGY NOTES. RESISTANCE VALUES SHOWN - - ---- - • +5VF ARE IN OHMS, CAPACITANCE +IOVF 2 (PLL2l IN MlCROFARADS, AND INDUCTANCE A40 PHASE LOCK LOOP IN MICROHENRIES UNLESS R l3 OTHERWISE NOTED, VOLTAGE -CONTROLLED OSCILLATOR ( VCO>...
  • Page 173 Model 8340A - Service A41 PHASE LOCK LOOP 2 (PLL2) PHASE DETECTOR, CIRCUIT DESCRIPTION INTRODUCTION The purpose of the A41 PLL2 Phase Detector is to compare the phase of the A40 PLL2 vco output signal (after division by N2 on...
  • Page 174 Model 8340A - Service 19) is higher than the 500 kHz Reference (Pl pin 20). U3 serves as an amplifier to provide the high currents necessary to rapidly charge the integrating capacitor C7 in the following stage in the ANALOG INTEGRATOR/SAMPLE AND HOLD (Block .
  • Page 175 Model 8340A - Service output of the integrator is summed with other signals in U4 of OUTPUT AMPLIFIER (Block and ultimately controls the VCO frequency. In steady state conditions, TP3 will settle to a constant voltage which tunes the to the correct frequency.
  • Page 176 Model 8340A Service MP2, HUL2 /II DET OUT MP1, MP15 [];![] 08340-60047 A-2318-45 Figure 8C-27. A41 PLI.2 Phase Detector, Component Location Diagram 8-243/8-244 Scans by HB9HCA and HB9FSX...
  • Page 177 Model 8340A Service PLL2 Phase Detector, Pin l/0 Mnemonic Levels Source Destination A62 STAR GND A62 STAR GND HLE2 TTL !HIGH TRUE) XA59P1-53 *A B C A62 STAR GND A62 STAR GND HUL2 TTL !HIGH TRUE) XA59P1-107 DIV N2 TTL ILDW TRUE)
  • Page 178 • • ••• • • NOTES: REFER THE BEGINNING OF LOCK LOOP 2 (PLL2) PHASE_ DETECTOR SECTION VIII FOR ® DIGITAL INTEGRATOR UP-DOWN COUNTERS r DAc, DETAILED SCHEl.!ATIC DIAGRAM rSW!TCHED OSCILLATORS,_ +5VF +20VF NOTES. r-COMPARATORS--._ +5VF 2. RESISTANCE VALUES ARE IN +I ,CT,,, 1 5 OHMS, CAPACITANCE IN J2.
  • Page 179 Model 83 40A - Service A42 PHASE LOCK LOOP 2 (PLL2) DIVIDER, CIRCUIT DESCRIPTION INTRODUCTION The PLL2 Divider Board has two functions: Generate the 500 kHz reference signal which is used by the � PLL2 Phase Detector Board. This is accomplished by dividing the lOMHz quartz crystal reference oscillator by 20.
  • Page 180 Model 8340A - Service divide by 10 output of U4 drives Ul6, whose divide by 2 output goes to the A41 PLL2 Phase Detector. This 500 kHz signal is used as a reference to which the programmable divide output of the The TTL input on Pl-2 PLL2 Divider is compared.
  • Page 181 Model S340A - Service sent to the presettable counter US. Ul5 is also presettable but is always preset to 0 (Ul5 is most significant digit). produces a HIGH output at a US and Ul5 count of 25 but because four additional clock pulses are required for this signal to get through UlOB and UlOA the cycle lasts for four more clock pulses.
  • Page 182 Model 8340A - Service non-integer divide numbers. The fractional counter block contains rate multipliers U5 and U6 and one shot multivibrator Ull. The rate multipliers produce Ml M2 pulses (Ml M2 is a two digit BCD number) for 100 pulses input, or the frequency out is ·(Ml M2 / 100) times the frequency in.
  • Page 183 Model 8340A Service DIRECT DIVIDE PRESCALER .. 20 Q 1- -- -- -- -- --<1>- -- -7 DIVIDED OUTPUT CLOCK 76-J60MHz +I 0/ I I FROM PLL2 VCO + 29 LRESET LSWALLOW INTEGER COUNTER LRESET CLOCK STOP SWALLOW SYNCHRONIZER STOP SWALLOW EARLY HLE2 >--- --�...
  • Page 184 Model 8340A Service CLOCK & COUNT PRESET UIOB Q UIOA LRESET IF UJ EARLY J (STOP SWALLOW HIGH r--- LSWALLOW + 10 + 10 STOP SWALLOW U7 COUNT PRESET T O 6 16 CYCLES +JI FOR CYCLES Figure BC-30. Partial Circuit Timing for+ 215 Example...
  • Page 185 Model 8340A - Service 75-150 MHZ MP 7 MP1, 10 MHZ • � " " � [fil]J B 0 8 � 0 1 7 � 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Figure SC-31.
  • Page 186 Model 8340A Service PLI.2 Divider, Pin I/0 Destination Source Mnemonic Levels XA59P1-109 LCK2 TTL !LOW TRUE) XA59P1-54 LCK1 TTL !LOW TRUE) *C 0 TTL !HIGH TRUE) XA59P1-53 HLE2 A62 STAR GNO XA60P1-76 XA60P1-20 XA60P1-77 XA60P1-21 XA60P1-7B XA60P1-22 XA60P1-79 XA60P1-23 0811...
  • Page 187 Scans by HB9HCA and HB9FSX...
  • Page 188 Model 8340A - Service A43 PHASE LOCK LOOP 2 (PLL2) DISCRIMINATOR, CIRCUIT DESCRIPTION INTRODUCTION The A43 PLL2 Discriminator Assembly contains the discriminator used to control the PLL2 vco. The sensitivity of the discriminator is adjusted by control signal N2 Tune into CURRENT...
  • Page 189 Model 8340A - Service (Block The input to the discriminator is used to trigger a very stable 1.6 microsecond pulse. The current source is activated by this pulse, and outputs a fixed amount of current for 1.6 microseconds. These current pulses are averaged to yield some net current flow that is proportional to the frequency of the input to the discriminator�...
  • Page 190 Model 8340A - Service pin 14 towards Vee until the U6 input circuit trips, reseting U6 and preventing a latch-up condition. The pulse width at TP2 should be equivalant to eight pulses at TP3. CURRENT SOURCE With the tuning voltage input...
  • Page 191 Model 8340A - Service O,Rl: (channel O, subchannel 1). The data programs DAC Ull, whose output goes to UlO. If the input is all zeros, the output of UlO is zero volts. The 1.5 mA into the summing node must then come entirely.from the discriminator...
  • Page 192 Model 8340A - Service Pretune current Discriminator current Sweep current 1.5 mA The sensitivity of this node is 5mA/MHz; that is, if 0.005mA of sweep current is added to the node, the input to the PULSE GENERATOR (Block will decrease by 0.001 MHz, causing the discriminator to reduce its output current by 0.005mA,...
  • Page 193 Model 8340A - Service IOMHz REF FROM VCXO SAMPLE HOLD SENSITIVITY FINE ADJ ,------------ 300KHz DISCRIMINATOR I= I 6mA@-300KHz • BLOCK A AND B I=O, 76mA ®I 50KHz 160MHz l o (AVG>:::: :: :: 6mA/MHz 0.6 = IOOMHz PRE TUNE...
  • Page 194 Model 8340A Service ---, PIO U2 - --, FEED FORWARD PATH R3 I CURRENT SOURCE TUNING VOLTAGE p 1-28 PRE TUNE R4 I I .5MA r - -1 R2.7 20 TO 30 SWEEP IN p 1-1 AF SWEEP ATTENUATOR [E] Figure 8C-34.
  • Page 195 Model 8340A Service Rlf1 MPlf, llF 5MHZ .5MHZ VCO TUNE OUT , 2MHZ MP16 MP1 2 .aMHZ MP11 .1s-.aoMHZ MP15 c:ru:! MP11f ��� @> o;i] + ca 000000000000000000 MP10 Figure 8C-35. A43 PLLJ Discriminator, Component Location Diagram 8-269/8-270 Scans by HB9HCA and HB9FSX...
  • Page 196 Model 8340A Service PLI.2 Discriminator, Pin J/0 Source Destination Mnemonic Levels 20/30 SWP 0 TD +10V XA58P1-41 LCK3 TTL !LOW TRUE) XA59P1-108 HLE2 TTL !HIGH TRUE) XA59P1-53 *NOT USED RGND A62 STAR GND TTL jLOW TRUE) XA60P1-76 TTL !LOW TRUE)
  • Page 197 NOTES I , REFER ---- - -·�--- • TO THE SERVICE SECTION IN TRODUCTION FOR DETAILED SCHE MATI C DIAGRAM SYMBOLOGY NOTES. 2. RF.SISTANCE VALUES SHOWN ARE IN OHMS, A43 PHASE LOCK LOOP CAPACITANCE IN MICROFARADS, AND (PLL2) +5VR +zovr 1 ®...
  • Page 198 Scans by HB9HCA and HB9FSX...
  • Page 199 REFERENCE GUIDE TO SERVICE DOCUMENTATION Description Bottom View Alpha Display • Display Dnver • Display Processor • Not Assigned Keyboard • Keyboard Interface • lower Keyboard • 3.7 GHz Oscillator • Band Pulse Modulator • Directional Coupler • Band 1-4 Detector •...
  • Page 200 SWEEP GENERATOR - YO LOOP INTRODUCTION List of Assemblies Covered THEORY OF OPERATION Sweep Generator and YO Loop - Overall Description Sweep Generator Description YO Loop Assemblies - Description Sweep Generator and YO Loop - Simplified Block Diagram TROUBLESHOOTING TO ASSEMBLY LEVEL Sweep Generator and YO Loop - Detailed Troubleshooting Block Diagram REPAIR PROCEDURES INDIVIDUAL ASSEMBLY SERVICE SECTIONS...
  • Page 201 Model 8340A - Service SWEEP GENERATOR - YO LOOP INTRODUCTION This section provides information and instructions for troubleshooting, repairing, or replacing assemblies and components in the sweep Generator and the YO Loop. Information includes circuit descr�ptions, troubleshooting procedures, block diagrams,...
  • Page 202 Model 8340A - Service SWEEP GENERATOR/YO LOOP THEORY OF OPERATION SWEEP GENERATOR/YO LOOP - OVERALL DESCRIPTION The Sweep Generator and YO Loop circuitry generate the signals used to tune the YO according to the mode of operation selected. The assemblies included in this section are the A44 YO,...
  • Page 203 Model 8340A - Service Coil by the FM Coil Driver on the A49 YO Loop Phase Detector board. The low frequency portion· (<100 Hz) is summed with PRETUNE on the A55 YO Driver and applied to the YO Main Coil. This completes the YO Loop and phase-locks the YO.
  • Page 204 Model 8340A - Service band begins. The sum of the durations of the ramping portions of MKR RAMP will still equal the selected instrument sweep time. Narrow Band Sweep Sweep widths <5 MHz are achieved by sweeping the 20-30 Loop.
  • Page 205 Model 8340A - Service SWEEP GENERATOR DESCRIPTION Introduction The assemblies documented in this functional group that cause the frequency of the 8340A to sweep are A58 sweep Generator, A54 YO Pretune/Delay Compensation board, and A55 YO Driver. When the YO loop phase-locks at the start frequency of an...
  • Page 206 Model 8340A - Service In sweeps where the YO is to move less than 5 MHz, the 20-30 loop is swept and the YO loop remains phase-locked. Since the YO loop. is phase-locked to the 20-30 loop output, the YO frequency will follow that of the 20-30 Loop.
  • Page 207 Model 8340A Service the various sweep events (marker on/off, bandcross, and end of sweep) by monitoring MARKER RAMP. This is a zero to ten volt ramp generated by the A58 sweep Generator board. A buffered version of this, SWEEP OUTPUT, available on the front and rear panels.
  • Page 208 Model 8340A - Service YO LOOP DESCRIPTION Introduction The assemblies (documented in this functional group) that comprise the YO Loop are A44 YO, A45 Pre-Leveler, 7 GHz Low Pass Filter, A48 YO Loop Sampler, A49 YO Loop Phase Detector, YO Loop Interconnect,...
  • Page 209 Model 8340A - Service YO FM Coil Drive The FM Coil Driver (A49, Block I) has a 100 Hz high pass filter, so that only the high frequency (>100 Hz) portion of YO TUNE is applied to the YO FM Coil. The resulting output is the YO FM COIL DRIVE current.
  • Page 210 Model 8340A - Service YO LOOP A46 7 .o GHz OUTPUT A45 PRE- YO RF OUTPUT LOW PASS LEVELER FILTER ,, - - ------ - -- - ----- ---- ---- - - 1 A49 YO LOOP PHASE DETECTOR SENSE PHASE/...
  • Page 211 Model 8340A - Service SWEEP GENERATOR - YO LOOP TROUBLESHOOTING TO ASSEMBLY LEVEL YO LOOP TROUBLESHOOTING Introduction The YO UNLOCKED error condition can be caused by a number of different failure mechanisms. The YO Loop Troubleshooting Flow Chart, Figure 8D-2a, provides a systematic way to identify the board or boards at fault for the majority of the cases.

  • Page 212: Yo Frequency

    Model 8340A - Service power, then proceed to question 3. IS YO FREQUENCY WITHIN +25 MHZ? The correct YO frequency can be found by pressing [SHIFT] [M2] the front panel that will display the following: BAND YO FREQUENCY (MHz) Typically PRETUNE will tune the YO within +5 MHz. YO tune can...
  • Page 213 Model 8340A Service � IS HLEY HIGH? HLEY (High Lock Enabl� Yig oscillator) must be HIGH for the YO Loop to lock. If HLEY is LOW or intermittent, then troubleshoot the A59 Digital Interface board. If not, then proceed to question...
  • Page 214 Model 8340A - Service With the YO TUNE and FM COIL cables disconnected (and a 50 Ohm load on the YO TUNE cable, A49J2), the YO frequency accuracy should be within a +5 MHz window over the entire YO operating range.
  • Page 215 Model 8340A - Service SENSE voltage, TP4 on the A55 YO Driver board. (The SENSE voltage is related to the YO frequency by -2.4 V/GHz.) If the YO Main Coil is greatly mistuned, then no YO signal will be present. If...
  • Page 216 Model 8340A - Service If the error condition can only be made to occur in the SWEPT mode and CONTINUOUS SWEEP mode, then the error will be more difficult to resolve. Proceed to question 2 in this section. There are several mechanisms that could cause a YO Loop unlock in only the SWEPT mode;...
  • Page 217 Model 8340A - Service SWEEP GENERATOR TROUBLESHOOTING Introduction There are two basic failure modes that have to do with the sweep function of the instrument. O ne, the instrument is simply not sweeping. Two, it is sweeping, but the sweep is incorrect;...
  • Page 218 Model 8340A - Service then something off the board is at fault. Finally, look at LRSP, TPll, on the ASS sweep Generator board. If it is stuck LOW, troubleshoot this problem. If the three lines just discussed, LBX, HSP and LRSP are all HIGH, then the problem is indeed on the sweep Generator board.
  • Page 219 Model 8340A Service Table Sensitivity of 20-30 SWP Line 8D- l. SWEEP WIDTH SENSITIVITY 5 MHz > YO sweep width > 500 KHz 500 KHz/volt > YO sweep width > 100 KHz 50 KHz/volt 500 KHz 100 KHz > YO sweep width >...
  • Page 220 .OGHr REFER TO SERVICE SECTION NOTES ��� A45 DIRECTIONALr INTROOUCllON FOR - A T2 15dB +1oro+1SdElm PASS FILTER :,-_ OESCRIPllON Of SVWBOlOGV ATTENUATOR USED ON TH1S BLOCK DIAGRAM. A55EMBL 2.'3 TD 2. NOl ALL POWER SUPPLY lNTERCONNl':CTJOl-IS -23 TO-MdBm ARE SHOWN ON THIS BLOCK DIAGRAU. -'.tit>- 3.
  • Page 221 A54 YO A54 YO PRETUNE 1158 SWEEP YO DRIVER/ PRE TUNE DELAY COMP PRE LEVELER GENERATOR A47 SENSE RES DELAY COMP BLOCK E I 4l IS 16) IS THE YO A59 DIGITAL PRELEVELER 151 IS YO RF 17) IS PRETUNE 18) IS VSWP 19) IS L VSX MAIN COIL...
  • Page 222 Model 8340A Service REPAIR PROCEDURES Refer to the REPAIR PROCEDURES description in the beginning of Section VIII. Disengage W3 from where it connects to the YO Loop via a hole in the motherboard (refer to Figure 8I-8, View C, in the RF...
  • Page 223 YO Main Coil when Q2 is ON. CS is used to reduce the phase noise of the YO and is also effective in reducing the radiated susceptibility of the 8340A. The swept mode filter consisting of Rl,...
  • Page 224 Model 8340A Service RE llE CFACTORY SELECTED) A44A1J1 +5 V A44YO ( 10 PLACES) (2 PLACES) A44J2 RF OUT -40V RCllE (FACTORY SELECTED) +20V A-2221-45 (2 PLACES) A44A1J2 A44A1R4 (FACTORY ADJUSTMENT) YO FM COIL NOTE Refer to Sweep Generator YO Loop Troubleshooting Block Diagram for schematic of A44.
  • Page 225 Model 8340A - Service A45 DIRECTIONAL COUPLER A45 DIRECTIONAL COUPLER DESCRIPTION The A45 directional coupler divides the RF Output of the A44 YO into two paths. The output of the coupled arm go8s to A45Jl. This signal is attenuated by AT2 and goes through the A46 7.0 GHz...
  • Page 226 Model 8340A Service AT2J2 15. dB ATT ENUAT OR CTO A46 VIA W43) AT2JI A45J3 RF OlITPIIT A45JI CTO,A44 YO J2 VIA W42) CTO AISJ2 VIA WSI AND W3) Figure 8D-4. A45 Directional Coupler Component Location Diagram 8-308 Scans by HB9HCA and HB9FSX...
  • Page 227 Model 8340A - Service A46 7 GHz LOW PASS FILTER 1 GHz LOW PASS FILTER CIRCUIT DESCRIPTION The A46 7 GHz Low Pass Filter is connected by coaxial cables between the A45 Pre-leveler and the A48 YO Loop Sampler. It is...
  • Page 228 Model 8340A Service INPUT OUTPUT 2, a TO 7, 0 GHZ 2.a TO 7,0 GHZ FROM W4a AND TO W44 ANO A45 PAELEVELEA J2 A49U1J1 NOTE Refer to Sweep Generator Loop Troubleshooting Block Diagram for schematic of A46. A46 7.0 GHz Low Pass Filter, Component Location Diagram Figure 8D-5.
  • Page 229 Model 8340A - Service A47 SENSE RESISTOR ASSEMBLY A47 SENSE RESISTOR ASSEMBLY CIRCUIT DESCRIPTION The A47 Sense Resistor Assembly contains the high-power portions of the ASS YO Driver and the A28 SYTM Driver. (For the schematic of the A47 Sense Resistor Assembly, see schematics for A28 and A47Q l,.A47Cl, and A47R6 are part of the compound PNP...
  • Page 230 Scans by HB9HCA and HB9FSX...

  • Page 231: Motherboard Wiring List

    Model 8340A - Service A62J32 TO M7W2P1 PIN A47W2P1 Levels Mnemonic RGND PIN 1 SYTMDB PIN 2 -22V TD -39V SYTM COIL+ PIN 3 -4aV TD -25V PIN 4 -.BV TD -BV SYTMDC SYTMRES PIN 5 -.9V LOW BAND CW Note: Refer to A28 SYTM Driver Schematic Diagram and AB2 Mother­...
  • Page 232 Model 8340A - Service A48 YO LOOP SAMPLER INTRODUCTION The A48 YO Loop Sampler mixes the output of the A44 YO (via the A45 Pre-leveler and A46 7 GHZ Low Pass Filter) with the Nth harmonic of the output of the M/N-Reference Loop (M/N IN).
  • Page 233 Model 8340A - Service Gain Adjust After being filtered, the IF signal is applied to a common-emitter amplifier Q6 which has adjustable gain. IF Gain adjustment Rl can be adjusted to provide from 5 dB to 20 dB of gain.
  • Page 234 Model 8340A Service A50C1 3 A50C1 1+ A50C1 5 Al+9.J2 Al+9.J1 -1 ov IF OUT +20V -1 ov A-2202-1+5 MPI+ At+BU1 E1 ,E2.E3 A48 YO Loop Sampler, Component Location Diagram Figure BD-7. 8-317/8-318 Scans by HB9HCA and HB9FSX...
  • Page 235 Model 8340A - Service INSERT IN FRONT OF PAGE 8-319/8·320 A48U 1 SAMPLER !NOTE Bl - - (a--- -' - 2.3 TO 7.0 GHZ • 1 4.0 ·23.0 TO d8111 J 1 - 2.3 TO 7 .O GHz •22.0 TO -13,5 d8111 ·...
  • Page 236 • • A48 YO LOOP SAMPLER 08340-60028 NOTES: SECTION INTROO'JCTION F0\1 OETAILED SCHEM�TIC N OHMS CAPACITANCE U�LESS OlHI�,. STRJr L�N[ INIJUCTORS: O � :N WIDE, 2 rn �� � ::� i � LONG L9 : o. I lN WIDE. TH A 5000n P�OBE 1·...
  • Page 237 Model 8340A - service A49 YO LOOP PHASE DETECTOR INTRODUCTION The A49 YO Loop Phase Detector Board receives as inputs the Sampler IF signal and the 20-30 signal from the A36 PLLl vco. These signals are phase-compared and the result is integrated to produce the YO TUNE signal as well as the FM Coil Drive signal, which are its main outputs.
  • Page 238 Model 8340A - Service unwanted frequencies which may have been introduced during the sampling process. IF Limiter B and 20-30 Limiter Sampler IF IN and 20-30 REF IN, Each of the two input signals, are passed through a limiter to establish ECL signal levels and to sharpen the edges of the two signals.
  • Page 239 Model 8340A - Service Integrator U4 has a pole at f=O and a zero at f=4000 Hz (Rl7 and Cl9) . Integrator U7 has a pole at f=O and a zero at f=400 Hz (Rl9 and C21}. The Phase-Lag Filter...
  • Page 240 Model 8340A - service input to the Sample and Hold circuit is used directly to tune and phase-lock the YO. This occurs: When the instrument is in the CW/MANUAL mode or in the swept mode for YO sweep widths less than 5 MHz. This means that the YO is phase-locked during the entir�...
  • Page 241 Model 8340A - Service current (through R36) to the YO FM Coil. A Phase-Lag Filter is incorporated in the feedback of the amplifier which completes the YO Loop frequency response ·and improves the overall noise performance of the YO Loop. The output voltage signal is clamped (by VR4 and VR5) to a maximum of +3.8V to prevent the...
  • Page 242 · ··· '- Model 8340A - Service ground through R37. Transistor Ql and surrounding circuitry form a capacitance multiplier circuit used to provide a filtered +15V supply, TPl, for the Differential Amplifier, Block E. The output voltage is determined by the _voltage divider of R49 and R50 less the 0.6V base-emitter voltage drop.
  • Page 243 Model 8340A - service A49 YO LOOP PHASE DETECTOR TROUBLESHOOTING YO Unlock A YO UNLOCK error condition can be caused by a number of different failure mechanisms in any of a number of assemblies. When the YO UNLOCK indicator is on, the YO Loop Troubleshooting Procedure should first be used to determine which assembly is at fault.
  • Page 244 Model 8340A -.Service correct output waveforms are described in the circuit theory section for the Phase Frequency Detector, Block D. Use a 10:1 test probe with a short ground clip. If the grounding is not good, there will be ringing on the signal edges. Also refer to the Open Loop Test, below.
  • Page 245 Model 8340A Service Tahle 8D-2. Bias Voltages on A49Q3 Under Different Loop Conditions loop Condition Emitter Base Collector Bose Collector Emitter (pin 1) (pin 4) (pin 2) (pin 3) (pin 6) (pin 5) LOCKED -1.5 v +15.0 v -0.9 v -1.5 v...
  • Page 246 Model 8340A - service Open Loop Test The following is an open-loop test that can be used to troubleshoot the A49 YO Loop Phase Detector. Set the instrument to CW mode. Disconnect the cables at A49Jl and A49J2, and measure the YO TUNE voltage at A49J2.
  • Page 247 Model 8340A - Service Al+SJI+ A50C10 A5DC9 ASOCll 20/30 MH'Z Al+SJ9 A50C11 Al+BJ1 A50C12 HULY -10v -a.2v IF OUT +20V 20/30 MH'Z OUT VO FM COIL HLEY 2 PLACE'S Figure BD-9. A49 YO Loop Phase Detector, Component Location Diagram 8-329/8-330...
  • Page 248 Model B340A - Service A50 YO LOOP INTERCONNECT BOARD A50 YO LOOP INTERCONNECT BOARD CIRCUIT DESCRIPTION · A50 YO Loop Interconnect board is used to dis tribute power and signals to the A48 YO sampler Assembly, the A49 YO Phase Detector, the A45 Directional Coupler, and the A44Al YO Bias...
  • Page 249 Model 8340A Service +5.2V -40V COIL -5.2V A50W2 TP1D TPS TPB - 5 - 117,-39 l_j!Q_ 1.§.. � � m::J YD LOCK � A-222\1-45 0X 4 oxa ox1 oxa (C11) []!RJ CC12) c ca) c cs' c ci a) TP4 TP:il X1 TP2 TP1...
  • Page 250 ---------·-· Model 8340A Service A62J2 A50W1 P2 PIN 1/0 A50W1P2 Mnemonic Levels -5.2V -5.2V PIN 2 HLEY PIN 3 rn !HIGH TRUEI +5.2V PIN 4 +52V rn !HIGH TRUE] HFILYD YD COIL + PIN 6 -40V TD -20V -/-40V PIN 8 -40V YD COii.
  • Page 251 " A49 A49 A<lg A49 TP4 TP5 TP2. TP3 " • " TP 10 TP I TPB TP9 TP? TPT TP� • • • • ••• ••• • " - ---- - ---- - - - • • • • - - ---- - - - �--- - ---- -...
  • Page 252 Model 8340A - Service A54 YO PRETUNE/DELAY COMPENSATION INTRODUCTION The A54 YO Pretune/Delay Compensation board performs three major functions: It provides a de voltage, Pretune, to the A55 YO DRIVER which � is proportional to the frequency to which the YO is being phase-locked.
  • Page 253 Model 8340A - Service The formula for calculating the digitized number that is present at the input of U6 at any given frequency is: [Lock frequency (GHz) - 2.3 (GHz)] 870. � Note that the latches pick off data bits 1-12, NOT 0-11. This means that the number sent by the processor and the number that shows up at the input of the DAC differ by a factor of 2.
  • Page 254 Narrow sweeps are sweep widths 500 kHz. � LVSX is HIGH any time that the 8340A is in the sweep mode and the sweep width is >500 kHz. Therefore, any slight de offset that might be at the output of the sweep generator when it is reset (and supposed to be at zero) is added to the PRETUNE voltage while the instrument is acquiring phase-lock.
  • Page 255 Model 8340A - Service generate the (A + B*F) term. (This is done through resistors R30 through R34.) The resulting voltage is used as the analog input to an 8 bit DAC whose digital input, provided by the processor, is related to the sweep rate, dF/dt. The DAC then performs the multiplication, and thus the voltage, called VCOMP, is of the desired form.
  • Page 256 Model 8340A - Service When the trigger pulse (TYOKP, Trigger YO Kick Pulse) is received from the processor, U9 is reset and Ql is turned on through U7B. When U9 is reset, pin 8 goes HIGH turning Q4 off through U7D. The...
  • Page 257 Model 8 340A - Service A54 YO PRETUNE/DELAY COMPENSATION TROUBLESHOOTING In all modes, the sensitivity of the PRETUNE output, TP3, is -2.5 volts/GHz. This is the place to start in troubleshooting the board. In CW mode, run the frequency from 2.3 GHz to 6.99 GHz and see if the correct voltage is present on the PRETUNE test point.
  • Page 258 Model 8340A Service BLVSX COFF CID]] � C3'+ c a 2 R3 7 000000000000000000 Figure 8D-12. A54 YO Pretune/Delay Compensation, Component Location Diagram 8-343 Scans by HB9HCA and HB9FSX...
  • Page 259 Model 8340A Service A54 YO Pretune DAC/Delay Compensation Pl Pin l/O Destination Mnemonic Levels Source +2aV +2aV XA52P1-16, 4a +2aV +2aV XA52P1-16, 4a +5.2V +5.2V XA52P1-17, 18, 41, 42 +5.2V +5.2V XA52P1-17, 18, 41, 42 -4aV/-4aV SENSE (-) -4aV XA53P1-11, 3a/XA53P1-23...
  • Page 260 " ----· - - ---- "' " " " • • • • ---- · ---- NOTES oa34o-sao PRETUNE/DELAY CCMPENSATION 8-)( REFER FIGUHF. F O R DETAILED SCflEMATIC D I AGR AM NOTES. RESISTANCE VALUES Af1E IN OHMS, C APACITANCE IN MICR OFl\RllDS, AND INDUCTANCE IN MICROllEN R I E S UNLESS OTflERWISE NOTED .
  • Page 261 Model 8340A - Service A55 YO DRIVER ASSEMBLY INTRODUCTION The YO Driver board performs several functions in the 8340A. It acts as a voltage to current converter to transform the � Pretune voltage (sensitivity -2.5 Volts/GHz) to YO MAIN COIL current (sensitivity is approximately 24 ma/GHz).
  • Page 262 Model· 8 340A - Service upsetting the feedback loop. several signals are summed at the feedback point. The delay compensation voltage, VCOMP, is applied through Q4 in Main summing Amplifier, Block F, and a 411 kHz low pass filter formed by ca and R55.
  • Page 263 Model 8340A - Service slew rate of the Discrete Op-Amp so Q7 and Q9 serve as speed up transistors by shunting resistor Rl3 when the Op-Amp is slewing and when the voltage across the resistor is sufficient to turn on one of the other of the transistors.
  • Page 264 Model 8340A - Service YO Error/Offset Summing Amp The OFFSET voltage is derived from a 6.2 volt reference zener. R47 provides an adjustment for this voltage and R48 with Cl5 provide noise filtering. The YO phase-locked loop error voltage, YO TUNE,...
  • Page 265 Model 8340A - Service where: and F are the frequencies in GHz � � at wer measured previously in the procedure. Finally, set the instrument to CW at 2.3 GHz and adjust the OFFSET Adjust R47 so that the YO frequency is 2.3 GHz.
  • Page 266 Model 8340A Service VCOMP SUMMING CURRENT I KHz SUMMING NODE � TUNE I KHz SUMMING AMP 2 SENSE RESISTOR COMPLIMENTARY DARLINGTON PNP TRANSISTOR DISCRETE OP-AMP L. - - PRETUNE ---- -- -� GAIN ADJUST COIL -40V Figure BD-14. A55 YO...
  • Page 267 Model 8340A - Service RGND YO TUNE OFFSET SENSE GAIN 6 PLACES Figure 8D-15. A55 YO Driver, Component Location Diagram 8-353 Scans by HB9HCA and HB9FSX...
  • Page 268 Model 8340A Service ASS YO Driver Pl Pin Source Destination Mnemonic Levels +20V +20V XA52P1-16, 40 +20V XA52P1-16, 40 +20V +5.2V +5.2V XA52P1-17, 18, 41, 42 +5.2V +5.2V XA52P1-17, 18, 41, 42 XA53P1-11, 30/XA53P1-23 -40V/-40V SENSE -40V *G/NOT USED -4ov...
  • Page 269 Scans by HB9HCA and HB9FSX...
  • Page 270 20-30 SWP (TP8). VSWP is the ramp voltage that will sweep the YO over the frequency range of interest. When the 8340A is set for a sweep width of greater than or equal to 500 KHz and the entire sweep is contained on one band,...
  • Page 271 Figure 1 in Table 1-1, Specifications, specific bandcross information versus swept mode used. It is because of this harmonic operation of the 8340A that bandcrossings are necessary. At each crossing, VSWP resets to zero and the YO is phase-locked to the appropriate frequency for the start of the next band.
  • Page 272 Serv i ce Model 8340A selected i nstrument sweep t i me. That i s to say, equal the sweep t i me of the i nstrument i s the t i me dur i ng wh i ch the i nstrument i s actually sweep i ng and does not i nclude the re-pha se-lock t i me at each bandcross i ng.
  • Page 273 Model 8340A Service S•SLOPE U+A 2+A 3 +A 4 +A6•10V +10V ·-· I J I I MKR I I I I RMP· I J I 1VSWP l!.. 4 FUNDAMENTAL 3 rd 4 th BAND BAND HARMONIC HARMONIC HARMONIC Figure Marker Ramp and VSWP Waveforms 8D-17.
  • Page 274 Model 8340A - Service A58 SWEEP GENERATOR CIRCUIT DESCRIPTION sweep Time Register U20 and U22 latch digital information from the instrument Data Bus which is then sent to the sweep Time DAC (Block G) • strobe for these two latches is l,Rl:, WSPTM (Write sweep Time).
  • Page 275 Model 8340A Service MARKER RAMP - SINGLE-BAND CASE VOLTS + 10 1'4-- Instrument Sweep Time MARKER RAMP - MULTI-BAND CASE VOLTS f-T2-i f+-T3--I Instrument Sweep Time Figure 8D-J 8. Typical Marker Ramp Waveforms 8-362 Scans by HB9HCA and HB9FSX...
  • Page 276 Model 8340A - Service sweep Width Register U34 is a latched 3 to 8 decoder which latches information from the instrument Data Bus and feeds it to the sweep Width Range Switch Driver (Block A given line is selected when it is a LOW.
  • Page 277 Model 8340A - Service The Sweep Time OAC (Block and the Sweep Time Scaling Resistors (Block I) function together as a current source that produces a current proportional to the selected sweep time. The higher the current, the shorter the sweep time. The Sweep Time OAC...
  • Page 278 Model 8340A Service RAMP GENERATOR R4,6 VIRTUAL GROUND AMPLIFIER CURRENT SHUNT U35B -15V RESET AMPLIFIER 1 Figure 8D-19. Simplified Ramp Generator 8-365 Scans by HB9HCA and HB9FSX...
  • Page 279 Model 8340A - Service When· the sweep is reset, switch Sl (Q6) in Reset Amplifier 1 (Block R) is closed. Since the non-inverting input of U l4 is grounded, it forces the inverting input to be at ground also. To...
  • Page 280 Model 8340A - Service (Block continues to sweep up to +lOV. This pause in the ramp will occur once at each bandcrossing. CR3 keeps U35B from sourcing current through CR2 and into C30. Because any stray current flowing into C30 will cause an error, a guard trace surrounds the entire node comprised of C30, pin 3 of U9, the cathode of CR2, and the source of Q6.
  • Page 281 Model 8340A - Service voltage change of each summing amplifier ramp is added together, the total will equal 10 volts, regardless of the number of ramps during one sweep. sweep Width DAC The Sweep Width DAC performs two functions. First,...
  • Page 282 Model 8340A � Service switch pull-up resistors. When a FET is on, the voltage at its gate should be equal to VSWP. When the FET is off, the gate voltage should be approximately -15 volts. In sweep widths where the YO would be sweeping less than 5 MHz, the 20-30 Loop is swept and the YO loop stays phase-locked.
  • Page 283 Model 8340A - Service instrument processor which pulls down HSP (High sweeP) on the A57 Marker Band cross board. HSP going LOW causes the LOW ENABLE RESET AMP 2 line to go LOW. This in turn forces LHLD (Low Hold Sweep,...
  • Page 284 Model 8340A Service E ND OF SWEEP ST A RT O F SWEEP ENO OF SWEEP START OF SWEEP ® LOW ENABLE RESET AMP2 LRSP ® LRESET LHLD LSPLD END OF SWEEP BANDCROSS SEQUENCE SEQUENCE Figure 8D-20. Sweep Control Logic Timing Diagram...
  • Page 285 Model 8340A - service When the processor is ready for the next sweep, it lets HSP go HIGH. This causes LOW ENABLE RESET AMP 2 to go LOW. This forces LRESET HIGH and LSPLD LOW, and the sweep proceeds. At a bandcrossing,...
  • Page 286 Model 8340A - Service C26, R43 and R44 are loop compensation components. Reset Control Logic At any phase-lock event LOW ENABLE RESET AM P (Block goes LOW. Then the instrument processor writes to the Reset Register (Block This LOW-going strobe,...
  • Page 287 Model 8340A - Service LBX is an open-collector line that can be pulled down by several boards. Ql3 provides the open-collector function on this board and buffers the output of U l OA so that by looking at TP5, the HBX...
  • Page 288 Model 8340A - service SWEEP GENERATOR TROUBLESHOOTING There are two basic failure modes that have to do with the sweep function of the instrument. One, the instrument is simply not sweeping. Two, it is sweeping, but the sweep is incorrect;...
  • Page 289 Model 8340A - Service Incorrect Sweep If the Marker Ramp waveform is correct, but the output of the SWEEP GENERATOR is still incorrect, then the various gain and attenuation stages must be checked. Set the instrument to sweep from 2. 3 GHz to 7 GHz with a sweep time of 10 msec. The voltage...
  • Page 290 Scans by HB9HCA and HB9FSX...
  • Page 291 M P7 (C.R 2,a ) TP� Tl"IO TPI\ TP\2. TPl'a SEE DETAii... A MPll MP10 2. PL.C.. 'i:> 2. PL.C:.'i> �HlG:: L D OETAIL Figure 8D-21. A58 Sweep Generator, Component Location Diagram 8-377 /8-378 Scans by HB9HCA and HB9FSX...
  • Page 292 Model 8340A Service Sweep Generator Pl Pin I/O (1 of 3) Levels Source Destination Mnemonic GND PLANE INSTRUMENT GROUND GND PLANE INSTRUMENT GROUND LSPLD A62J1-44 HIGH TRUE XA57P1-13 XA54P1-9 F LVSZ LOW TRUE LIPS LOW TRUE *NOT USED LOW TRUE...
  • Page 293 Model 8340A Service Sweep Generator Pl Pin 1/0 (2 of 3) Mnemonic Levels Source Destination XA60P1-20 *A 8 E ·m GND PLANE INSTRUMENT GROUND XA60P1-21 - *A 8 E XA60P1-76 *A 8 E XA60P1-22 *A 8 E XA60P1-77 *A 8 E...
  • Page 294 Model 8340A Service Sweep Generator Pl Pin l/0 (3 of 3) Mnemonic Levels Source Destination -15V -15V XA56P1-15, 30 -5.2V -5.2V XA53P1-18, 36 *NOT USED XA53P1-12, 13, 31, 32 -10V -10V -10V -10V XA53P1-12, 13, 31, 32 BVSWP 1 OV SWEEP...
  • Page 295 A58 SWEEP GENERATOR 08340-60154 +ll V F ®SWEEP WIDTH REGISTER +5VF ®SWEEP WIDTH RANGE SWITCH DRIVER Fl70 t�5VR DB12 C 5 7 DB 1 3 U 3 4 • DB1d @SWEEP BUFFER U 3 9 7 A i1 4V.: I I tl! '>---.-+---' - --+--' <> =�p:�...
  • Page 296 Scans by HB9HCA and HB9FSX...
  • Page 297 REFERENCE GUIDE TO SERVICE DOCUMENTATION Description Bottom View Alpha Display Display Driver Display Processor Not�signed Keyboard Keyboard Interface Lower Keyboard Oscillator Band Pulse odulator • .Directional Go. v pler Band Detector • /\ 1 . 2 . Band Splitter/Detector ® SYTM (Switched YIG Tuned Multiplier) Band 1-4 Power Amplifier Band 0 Low Pass Filter...
  • Page 298 MOTHERBOARD - WIRING LIST INTRO DU CTI ON List of Assemblies Covered A62 MOTHERBOARD DESCRIPTION A62 MOTHERBOARD TROUBLESHOOTING REPAIR PROCEDURES MOTHERBOARD WIRING LIST Scans by HB9HCA and HB9FSX...
  • Page 299 Model 8340A - Service A62 MOTHERBOARD Introduction This section consists of the following items: A62 Motherboard description. � Information concerning Motherboard troubleshooting techniques � which includes a component location diagram and Motherboard repair and replacement procedures. A Motherboard wiring list that identifies signal mnemonics, �...
  • Page 300 Model 8340A - Service A62 MOTHERBOARD DESCRIPTION Introduction The A62 Motherboard is the common board to which numerous other assemblies are connected and serves to route signals to other printed circuit boards where needed. The A62 Motherboard is large and complex: it contains six trace layers with several hundred seperate signal paths.
  • Page 301 ANALOG SIGNALS DIGITAL GROUND PLANE DIGITAL SIGNALS DIGITAL SIGNALS DIGITAL GROUND PLANE ANALOG SIGNALS Figure 8E-1. A62 Motherboard Cross Section 8-390 Scans by HB9HCA and HB9FSX...
  • Page 302 Model 8340A - Service As shown in Figure 8E-l, A62 Motherboard Cross Section, the GND PLANE exists between the two innermost and two outermost Motherboard printed circuit layers. These layers were designed to disperse any digital noise into the GND PLANES and act as an electrostatic shield between the digital and analog signal traces.
  • Page 303 Model 8340A - Service A62 MOTHERBOARD TROUBLESHOOTING Introduction Troubleshooting the A62 Motherboard is straightforward since the most common problems encountered are opens and shorts. Table 8E-l, A62 Motherboard Wiring List is included in this manual in lieu of an A62 Motherboard schematic diagram.
  • Page 304 Model 8340A - Service REPAIR PROCEDURES Int roduction Repair and replacement of A62 Motherboard components and connectors is possible but successful only when the following guidelines are followed. Component And Connector Replacement NOTE Unless otherwise mentioned, do not use a...
  • Page 305 Model 8340A - Service Have one person gently grab and pull the pin to be replaced from the component side of the Motherboard while another person heats the pin from the other side. Reheat the pad and use solder wick or an anti-static solder removal tool to remove the solder from the hole.
  • Page 306 Model 8340A - Service questions concerning Motherboard replacement should be directed to your nearest Sales and service Center for more specific instructions. Refer to the Sales And Service Offices listing at the end of the Service section in this manual.
  • Page 307 Scans by HB9HCA and HB9FSX...
  • Page 308 Model 8340A - Service A62 MOTHERBOARD SOLDER SIDE � � MP I (SOCKETS : "' "' PLACES) � � . � • • • Jll Jl3 Jl5 @)@)@) � J25 J26 ® ® @)@) � Jl 4 ru-s HEAT SINK...
  • Page 309 Model 8340A Service A62 MOTHERBOARD SOLDER SIDE (SOCKETS: PLACES) Jll Jl3 Jl5 @)@@0 J25 J26 ® � @)@) HEAT SINK --0..!. .i MPll (9 PLACES: LI -g) J5 JS @)@) Qill STAR GND J a @) J 9 @) J 2 7 @) Figure 8E-2.
  • Page 310 Table 8£-1. Motherboard Wirini T.isr (I of 7) SWEEP GENERATOR RF SECTION POWER SUPPLIES 20/30 LOOP Y/O LOOP CONTROLLER GROUNDS AND A62 MOTHERBOARD LOOP MISCELLANEOUS A62 MOTHERBOARD MNEMONICS MNEMONIC DESCRIPTION TYPE LEVELS SOURCE COMPONENTS GROUND PLANES A62 MOTHERBOARD WIRE COAX CONNECTORS - "' COLORS J4-J6 JB-Jl7,J21-J28...
  • Page 311 Scans by HB9HCA and HB9FSX...
  • Page 312 Scans by HB9HCA and HB9FSX...
  • Page 313 Table 8£-1. Morherboard Wiring List (4 of 7) SVlEEP GENERATOR 21!l/30 LOOP Y/O LOOP CONTROLLER RF SECTION POWER SUPPLIES LOOP MNEMONIC DESCRIPTION TYP£ LEVELS SOURCE MISCELLANEOUS A62 MOTHERBOARD GROUNDS AND A62 MOTHERBOARD MNEMONICS - "' - "' A62 MOTHERBOARD WIRE COAX CONNECTORS COMPONENTS GROUND PLANES...
  • Page 314 A62J31 PINS 2, 16 1.4V/GHZ 1.4V/GHZ 1.4V PER GHZ REFERENCE ANALOG 1.4V/GHZ XA28P1-7 5 MHZ CLK 5 MHZ CLI< 5 MHZ CLOCK TO HP(IB CHIP DIGITAL XA60P1-34 20/30 SWP 20/30 SWP 20(30 MHZ REFERENCE OSCILLATOR SWEEP ANALOG OV TO +10V XA58P1-41...
  • Page 315 Table 8E-l. Motherboard Wiring List (6 qf 7) SWEEP GENERATOR 20/30 LOOP Y/O LOOP CONTROLLER RF SECTION POWER SLPPLIES LOOP A62 MOTHERBOARD GROUNDS AND MNEMONIC DESCRIPTION TYPE LEVELS SOURCE MISCELLANEOUS A62 MOTHERBOARD MNEMONICS COMPONENTS GROUND PLANES R62 MOTHERBOARD WIRE COAX CONNECTORS - "' - CD �...
  • Page 316 Scans by HB9HCA and HB9FSX...
  • Page 317 REFERENCE GUIDE TO SERVICE DOCUMENTATION Description Bottom View - CD - @ @ HDetectQi• Ba�d � � ® SYTM (Switched VIG Tuned Multiplier) Band J.4 Power Amplifier Band Low Pass filler Band J.4 Modulalor/Spliller · iland Mixer • • · ·. •...
  • Page 318 Model 8340A Service FRONT PANEL STOP OVER ... 00 nEMOTE FAULT ov•� EXTR!F UNL< J5 RF OUTPUT REAR PANEL Option 004 and 005 only) HP-IB Connector =� = � =� Line Module Assembly Figure BF-1. Front and Rear Panels 8-415...
  • Page 319 Model 8340A - Service A2 DISPLAY A3 DISPLAY DRIVER PROCESSOR A1 ALPHA DISPLAY A6 KEYBOARD INTERFACE A? LOWER KEYBOARD Figure 8F-2. Front Panel Assemblies 8-416 Scans by HB9HCA and HB9FSX...
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