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SRS Labs SR785 Service Manual

Dynamic signal analyzer
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Service Guide
Model SR785
Dynamic Signal Analyzer
1290-D Reamwood Avenue
Sunnyvale, CA 94089 U.S.A.
Phone: (408) 744-9040 • Fax: (408) 744-9049
Email: info@thinkSRS.com • www.thinkSRS.com
Copyright © 1995, 1996, 1998
Stanford Research Systems, Inc.
All Rights Reserved
Revision 1.2 (October, 2004)

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  • Page 1 Service Guide Model SR785 Dynamic Signal Analyzer 1290-D Reamwood Avenue Sunnyvale, CA 94089 U.S.A. Phone: (408) 744-9040 • Fax: (408) 744-9049 Email: info@thinkSRS.com • www.thinkSRS.com Copyright © 1995, 1996, 1998 Stanford Research Systems, Inc. All Rights Reserved Revision 1.2 (October, 2004)
  • Page 2 Information in this document is subject to change without notice. Copyright © Stanford Research Systems, Inc., 1998. All rights reserved. Stanford Research Systems, Inc. 1290-D Reamwood Avenue Sunnyvale, California 94089 Printed in U.S.A. SR785 Dynamic Signal Analyzer Service Guide...

  • Page 3: Safety And Preparation For Use

    Contact the factory for instructions on how to return the instrument for authorized service and adjustment. The fans in the SR785 are required to maintain proper operation. Do not block the vents in the chassis or the unit may not operate properly.
  • Page 4 SR785 Dynamic Signal Analyzer Service Guide...

  • Page 5: Table Of Contents

    Required Equipment 3-10 Power Supply Board Replacement 3-10 Power Supply Check 3-11 CRT Replacement 3-13 CRT Check 3-14 Keypad Check 3-14 Knob Check 3-15 CPU Board Replacement 3-16 Battery Check 3-17 Video/IO Board Replacement 3-17 Service Guide SR785 Dynamic Signal Analyzer...
  • Page 6 Schematic Diagram List CPU Board MCPU-1 Video/IO Board MVID-1 Power Supply Board MPWR-1 System Backplane MBKPL-1 Disk Card MBKPL-24 Keypad Board MKEY-1 DSP Board D785-1 Analog Input Board A780-1 Analyzer Backplane M780-1 Demo Filter F780-1 SR785 Dynamic Signal Analyzer Service Guide...

  • Page 7: Table Of Figures

    Table of Figures Figure 3-1 System Components Figure 3-2 Analyzer Components Figure 3-1 System Components Figure 3-2 Analyzer Components Figure 3-3 Analog Adjustments 3-24 Service Guide SR785 Dynamic Signal Analyzer...
  • Page 8 SR785 Dynamic Signal Analyzer Service Guide...
  • Page 9 5. Amplitude Linearity 1-17 6. Anti-alias Filter Attenuation 1-19 7. Frequency Accuracy 1-21 8. Phase Accuracy 1-23 9. Noise and Spurious Signals 1-25 10. Sine Source 1-29 11. Harmonic Distortion 1-31 SR785 Performance Test Record 1-32 SR785 Dynamic Signal Analyzer...
  • Page 10 Performance Tests SR785 Dynamic Signal Analyzer...

  • Page 11: Getting Ready

    <Softkeys> The SR785 has a menu driven user interface. The Menu keys each display a menu of softkeys. The softkeys are at the right of the video display and have different functions depending upon the displayed menu.

  • Page 12: Firmware Revision

    Offset may invalidate the results of some tests. The Test Record Make a copy of the SR785 Performance Test Record at the end of this section. Fill in the results of the tests on this record. This record will allow you to determine whether the tests pass or fail and also preserve a record of the tests.
  • Page 13 Performance Tests If the test continues to fail, contact Stanford Research Systems for further instructions. Make sure that you have the unit serial number and firmware revision code handy. Have the test record on hand as well. SR785 Dynamic Signal Analyzer...
  • Page 14 Performance Tests SR785 Dynamic Signal Analyzer...

  • Page 15: Self Tests

    1) Reset the unit by pressing [System] <Preset> and then [Enter] to confirm. During re-boot, the DSP memory and calibration tests should all be OK. To review this power on screen, use [System] <Show Version>. 2) Press the keys in the following sequence: SR785 Dynamic Signal Analyzer...
  • Page 16 <Return> <Help ROM> <Begin> All of the memory chips should Pass. <Return> <Return> 3) This completes the functional hardware tests. Enter the results of this test in the test record at the end of this section. SR785 Dynamic Signal Analyzer...

  • Page 17: Dc Offset

    [-] [3] [0] [Enter] [Start/Reset] Wait for the average to finish. [Auto Scale A] [Auto Scale B] b) Record the marker Y values for both displays on the -30 dBV range. c) Press <Ch1 Input Range> SR785 Dynamic Signal Analyzer...
  • Page 18 Record the marker Y values for both displays for the -50 dBV range. 4) This completes the DC measurement test. Enter the results of this test in the test record at the end of this section. SR785 Dynamic Signal Analyzer...

  • Page 19: Common Mode Rejection

    Select (Linear/Fixed Len) [Enter] <# Avgs> [1] [0] [Enter] <Display Avg> Select (RMS) [Enter] Wait for the average to finish. [Auto Scale A] [Marker Max] [Marker Ref] [Input] <Input Config> <Ch1 Input Mode> Select (A-B) [Enter] SR785 Dynamic Signal Analyzer...
  • Page 20 6) Record the marker Y reading. This is the Ch2 CMRR (in dB) at 1 kHz. 7) This completes the CMRR measurement test. Enter the results of this test in the test record at the end of this section. SR785 Dynamic Signal Analyzer...

  • Page 21: Amplitude Accuracy And Flatness

    [1] [.] [6] Select (kHz) [Enter] <Center Freq.> [1] Select (kHz) [Enter] [Input] <Input Config> <Channel> Select (Both) [Enter] <Ch1 Coupling> Select (AC) [Enter] [Average] <Averaging Type> Select (Linear/Fix Len) [Enter] <# Avgs> [1] [0] [Enter] <Display Avg> Select (RMS) [Enter] SR785 Dynamic Signal Analyzer...
  • Page 22 48 kHz 72 kHz 96 kHz a) Set the AC calibrator to 1.0 kHz and an amplitude of 99.881 mVrms. b) Set the frequency synthesizer to 1.0 kHz. c) Press [Frequency] <Center Frequency.> [1] Select (kHz) [Enter] SR785 Dynamic Signal Analyzer...
  • Page 23 [Input] <Ch1 Input Range> [2] [2] [Enter] [Start/Reset] Wait for the average to finish. [Auto Scale A] [Auto Scale B] [Link] [Marker Max] The Y value of the marker should now read +19.0 dB (±0.15 dB). SR785 Dynamic Signal Analyzer...
  • Page 24 1-16 Performance Tests d) Repeat steps 4d through 4f above. 6) This completes the amplitude accuracy and frequency response test. Enter the results of this test in the test record at the end of this section. SR785 Dynamic Signal Analyzer...

  • Page 25: Amplitude Linearity

    <Window> Select (Flattop) [Enter] [Freq] <Span> [1] [.] [6] Select (kHz) [Enter] <Center Freq.> [1] Select (kHz) [Enter] [Input] <Input Config> <Channel> Select (Both) [Enter] <Ch1 Coupling> Select (AC) [Enter] <Ch1 Input Range> [2] [2] [Enter] SR785 Dynamic Signal Analyzer...
  • Page 26 Press [Start/Reset] and wait for the average to finish. c) Record the marker Y reading for both displays. 4) This completes the amplitude linearity test. Enter the results of this test in the test record at the end of this section. SR785 Dynamic Signal Analyzer...

  • Page 27: Anti-Alias Filter Attenuation

    <Ch1 AA Filter> Select (Off) [Enter] [Average] <Averaging Type> Select (Linear/Fix Len) [Enter] <# Avgs> [1] [0] [Enter] <Display Avg> Select On [Enter] [Start/Reset] Wait for the average to finish. [Auto Scale A] [Auto Scale B] SR785 Dynamic Signal Analyzer...
  • Page 28 Wait for the average to finish. Record the marker Y readings for both displays. 5) This completes the anti-alias filter attenuation test. Enter the results of this test in the test record at the end of this section. SR785 Dynamic Signal Analyzer...

  • Page 29: Frequency Accuracy

    4) Wait for the spectrum to settle (at least 5 seconds), then record the marker frequency reading for DisplayA. 5) This completes the frequency accuracy test. Enter the results of this test in the test record at the end of this section. SR785 Dynamic Signal Analyzer...
  • Page 30 1-22 Performance Tests SR785 Dynamic Signal Analyzer...

  • Page 31: Phase Accuracy

    <Ch1 Coupling> Select (AC) [Enter] [Trigger] <Trigger Source> Select (Ch1) [Enter] [Auto Scale A] [Auto Scale B] [Marker] <Marker> Select (Link) [Enter] [Marker Max] [Display Setup] <View> Select (Phase) [Enter] [Active Display] Make DisplayB the active display. SR785 Dynamic Signal Analyzer...
  • Page 32 4) Record the marker Y readings for both displays. (Make sure that the marker frequency is 10.24 kHz) 5) This completes the phase accuracy test. Enter the results of this test in the test record at the end of this section. SR785 Dynamic Signal Analyzer...

  • Page 33: Noise And Spurious Signals

    [-] [5] [0] [Enter] <Ch1 Coupling> Select (AC) [Enter] <Ch1 Grounding> Select (Ground) [Enter] [Display Setup] <Y mid> [Link] [-] [1] [5] [0] [Enter] [Display Options] <Units> <PSD Units> [Link] Select (On) [Enter] <Pk. Units> [Link] Select (rms) [Enter] SR785 Dynamic Signal Analyzer...
  • Page 34 5) Record the marker Y readings for both displays. 6) Press [Display Options] [Display Setup] <Units> <Pk. Units> Select (pk) [Enter] <PSD Units> Select (Off) [Enter] [Marker] <Seeks> Select (Max) [Enter] 7) For each of the spans listed below, perform steps 7a through 7c. SR785 Dynamic Signal Analyzer...
  • Page 35 [Link] [Marker Max] c) Record the marker Y readings for both displays. 8) This completes the noise and spurious signal test. Enter the results of this test in the test record at the end of this section. SR785 Dynamic Signal Analyzer...
  • Page 36 1-28 Performance Tests SR785 Dynamic Signal Analyzer...

  • Page 37: Sine Source

    [1] [0] [0] [Enter] 5) Record the marker Y reading for DisplayA. 6) Press <Amplitude 1> [1] [0] [Enter] 7) Record the marker Y reading for DisplayA. 8) Press <Amplitude 1> [1] [0] [0] [0] [Enter] SR785 Dynamic Signal Analyzer...
  • Page 38 Press <Frequency 1> Enter the frequency from the table. [Marker Max] b) Record the marker Y reading for DisplayA. 8) This completes the source sine test. Enter the results of this test in the test record. SR785 Dynamic Signal Analyzer...

  • Page 39: Harmonic Distortion

    Make DisplayB the active display. 5) Record the THD reading for DisplayB (from the THD menu box). 6) This completes the harmonic distortion test. Enter the results of this test in the test record at the end of this section. SR785 Dynamic Signal Analyzer...

  • Page 40: Performance Test Record

    1-32 Performance Tests SR785 Performance Test Record Page 1 of 3 Serial Number __________________________ Tested By___________________________ Firmware Revision ______________________ Date _______________________________ Equipment Used _______________________________________________________________ _______________________________________________________________ 1. Self Tests Test Pass Fail Power On Test ____ ____ Keypad ____ ____ Knob...
  • Page 41 Performance Tests 1-33 SR785 Performance Test Record Page 2 of 3 4. Amplitude Accuracy and Flatness (Continued) Flatness relative to 1 kHz Input Range Frequency Lower Limit DispA (Ch1) DispB (Ch2) Upper Limit 22 dBV 24 kHz 18.80 dBV _______ _______ 19.20 dBV...
  • Page 42 1-34 Performance Tests SR785 Performance Test Record Page 3 of 3 10. Sine Source Amplitude Frequency Level Lower Limit DispA Upper Limit 1 kHz 1000 mV -0.3 dBV _______ 0.3 dBV 1 kHz 100 mV -20.3 dBV _______ -19.7 dBV...

  • Page 43: Cpu Board

    Chapter 2 Circuit Description This chapter provides descriptions of the circuitry in the SR785. Each circuit board’s function and operation is discussed. The schematics for each board are shown in Chapter 5. In This Chapter I/O Interface 2-13 Overview Trigger...
  • Page 44 Circuit Description SR785 Dynamic Signal Analyzer Service Guide...

  • Page 45: Overview

    Overview The SR785’s circuitry is divided into two major sections - the system section and the analyzer section. The system section contains the main processor (CPU), video display, external interfaces, power supply and front panel. The analyzer section contains the digital signal processor (DSP), source output and analog inputs.

  • Page 46: Schematic Diagram Locations

    MVID-10 through MVID-14 Power Supply MPWR-1 through MPWR-2 System Backplane MBKPL-20 through MBKPL-23 Disk Card MBKPL-24 Keypad Board MKEY-1 DSP Board D785-1 through D785-11 Analog Input Boards A780-1 through A780-7 Analyzer Backplane M780-1 through M780-4 SR785 Dynamic Signal Analyzer Service Guide...

  • Page 47: Cpu Board

    -PCS1 enables the peripherals on the Video/IO board. -PCS2 enables the AUX connectors on the System backplane. -PCS1 and -PCS2 enable the Expansion data bus. - PCS4 and -PCS5 enable the External (DSP) bus. -PCS4 enables processor addressable peripherals on the DSP board. Service Guide SR785 Dynamic Signal Analyzer...

  • Page 48: String Rom

    Only keyboards which operate in the PC or 8088 mode will function with this interface. Speaker The speaker is driven by a timer on the 80C186. The timer outputs a square wave which is enabled by U507A and drives the speaker through Q705. SR785 Dynamic Signal Analyzer Service Guide...

  • Page 49: Clock/Calendar

    Expansion Connector The 120 pin connector carries all of the necessary interconnections to the System backplane. Both the Expansion and External buses are carried off-board via this connector. Power is also delivered through this connector. Service Guide SR785 Dynamic Signal Analyzer...

  • Page 50: Video/Io Board

    U1101 is a dual DAC which programs the two current sources. Disk Controller U1201 is a DP8473 disk controller which integrates all of the functions of the PC disk interface into a single IC. All motor controls, read and write signals, and data are SR785 Dynamic Signal Analyzer Service Guide...

  • Page 51: Gpib Interface

    The 120 pin connector carries all of the necessary interconnections to the System backplane. Power is also delivered through this connector. Peripherals on this board are accessed whenever -PCS1 from the CPU is active. U1401 and U1402 provide on-board decoding. Service Guide SR785 Dynamic Signal Analyzer...

  • Page 52: Power Supply Board

    41VAC center tapped secondaries and two 26VAC secondaries. The 41VAC secondaries are used to generate ±20VDC supplies for the analog inputs and the source output. The 26VAC secondaries generate +30V isolated supplies for the ICP power. SR785 Dynamic Signal Analyzer Service Guide...

  • Page 53: Dsp Board

    ±20V_A (analog power) is on the analog input boards. This supply floats if no analog input board is plugged in. The +30V supplies are very low current and only require small 100 mA regulators U30 and U40. Service Guide SR785 Dynamic Signal Analyzer...

  • Page 54: Dsp Board

    Digital Signal Processor The SR785 utilizes a single ADSP21020 digital signal processor clocked at 33 MHz. All instructions are completed in a single 30 ns cycle. The ADSP21020 has two external data buses - Data Memory (DM) and Program Memory (PM).

  • Page 55: I/O Interface

    U604B and U612A provide low-frequency hysteresis. R623 and N602A determine the level of hysteresis. The DC trigger level is set by the 8-bit DAC U607B. U606D buffers and shifts the DAC output. Service Guide SR785 Dynamic Signal Analyzer...

  • Page 56: Source Generator

    DSP board. U805 is a decoder which generates the chip selects and strobes needed by the DSP board. U810 is a serial EEPROM which holds the calibration data required by the source and trigger circuits. SR785 Dynamic Signal Analyzer Service Guide...

  • Page 57: Analog Input Boards

    The design of the front end input amplifier in the SR785 was driven by an effort to provide optimum performance in the following areas: input voltage noise, input current noise, input capacitance, harmonic distortion, and common mode rejection (CMR).

  • Page 58: Anti-Aliasing Filter

    The outputs of the latches are used to control relays, switches, etc. During normal operation, this interface is static and no random digital noise is present on this board. SR785 Dynamic Signal Analyzer Service Guide...
  • Page 59 It is grounded by the Analog Input board to reduce ground loops at the analog inputs. Thus, the ±20 VDC floats when no Analog Input boards are present. If either Analog Input board is present, then this supply is grounded. Service Guide SR785 Dynamic Signal Analyzer...
  • Page 60 2-18 Circuit Description SR785 Dynamic Signal Analyzer Service Guide...
  • Page 61 3-20 Service Procedure F6 (Checking the Source) 3-21 Service Procedure F7 (DSP Memory Module Replacement) 3-21 Service Procedure G1 (Replacing the Disk Drive) 3-22 Service Procedure J1 (Adjusting the DC Offset and CMR) 3-24 Service Guide SR785 Dynamic Signal Analyzer...
  • Page 62 Service SR785 Dynamic Signal Analyzer Service Guide...

  • Page 63: Before Proceeding With Service

    DSP board or either Analog Input board is replaced (with factory calibrated replacement boards), the unit will remain calibrated. If individual components are replaced on a board, the calibration is not guaranteed. Individual component replacement on the DSP or Analog boards is not recommended. Service Guide SR785 Dynamic Signal Analyzer...

  • Page 64: Troubleshooting Table

    Video RAM check fails Replacement). • Proceed to Service Procedure D2 (Battery Check). Unit does not recall settings at power on. • Proceed to Service Procedure D2 (Battery Check). Clock does not keep time correctly SR785 Dynamic Signal Analyzer Service Guide...
  • Page 65 • Perform the disk drive test in the [System]<Diagnostics> menu. • Proceed to Service Procedure G1 (Disk Drive Replacement). • If there is still a problem, proceed to Service Procedure D3 (Video/IO Board Replacement). Service Guide SR785 Dynamic Signal Analyzer...
  • Page 66 RS232 port on the rear panel (NOT to the Printer port). Use a tested cable. • Check that the SR785 is set to output data to the RS232 interface (NOT the GPIB interface). The output interface is set in the [System]<Remote> menu.
  • Page 67 CMR). • Proceed to Service Procedure D1 (CPU Board Updated ROMS are available Replacement) for program ROMS (U301-306) and Help ROMS (U801-U802). • Proceed to Service Procedure F1 (DSP Board Replacement) for theDSP ROM Service Guide SR785 Dynamic Signal Analyzer...

  • Page 68: Circuit Board Locations

    Service Circuit Board Locations The SR785’s circuitry is divided into two major sections - the system section and the analyzer section. The system section contains the main processor (CPU), video display, external interfaces, power supply and front panel. The analyzer section contains the digital signal processor (DSP), source output and analog inputs.

  • Page 69: Analyzer Components

    MVID-10 through MVID-14 Power Supply MPWR-1 through MPWR-2 System Backplane MBKPL-20 through MBKPL-23 Disk Card MBKPL-24 Keypad Board MKEY-1 DSP Board D785-1 through D785-11 Analog Input Boards A780-1 through A780-7 Analyzer Backplane M780-1 through M780-4 Service Guide SR785 Dynamic Signal Analyzer...

  • Page 70: Service Procedures

    2. Remove the eight black screws which secure the top lid. There are four screws on each side, two at the front and two at the rear. Remove the lid by pulling the lid towards the back and upwards. SR785 Dynamic Signal Analyzer Service Guide...

  • Page 71: Service Procedure A2 (Power Supply Check)

    GND (green) wires on the rear panel chassis ground connection (above the power switch on the inside). One green wire connects directly to the power entry module ground, the other to the System backplane via the AC power connector. Service Guide SR785 Dynamic Signal Analyzer...
  • Page 72 +12V -12V ±5% +5V ±5% Ground ANLG Power Test Point Nominal -28V <-23V +28V >+23V -20V -20V ±5% +20V +20V ±5% AGND Test Point Nominal +30V +30V ±5% Test Point Nominal +30V +30V ±5% SR785 Dynamic Signal Analyzer Service Guide...

  • Page 73: Service Procedure B1 (Replacing The Crt)

    8. Gently slide the CRT enclosure forward until the front of the CRT just touches the plastic anti-glare screen. Slide the CRT back 1/8” so that the front of the CRT is just behind the anti-glare screen. Tighten the four screws to secure the enclosure in place. Service Guide SR785 Dynamic Signal Analyzer...

  • Page 74: Service Procedure B2 (Crt Check)

    7. The keypad and knob are attached to the Disk card by a ribbon cable. This cable attaches next to the Keyboard connector below the CRT. The cable attaches to the SR785 Dynamic Signal Analyzer Service Guide...

  • Page 75: Service Procedure C2 (Knob Check)

    10. Push the Disk card inward to make sure that it is seated properly. The knob signals are carried to the System backplane via this card. 11. If the knob still fails to function, proceed to replace the digital pot. Service Guide SR785 Dynamic Signal Analyzer...

  • Page 76: Service Procedure D1 (Cpu Board Replacement)

    8. Insert the new board making sure to align the board edges with the plastic card guides before pressing the board into place. Make sure that the board is seated completely in its socket. SR785 Dynamic Signal Analyzer Service Guide...

  • Page 77: Service Procedure D2 (Battery Check)

    4. See Figure 8-1 to locate the Power Supply board. Make sure that the red LED at the top edge of the board is OFF before proceeding. Release the bar which secures the boards in place. Service Guide SR785 Dynamic Signal Analyzer...

  • Page 78: Service Procedure F1 (Dsp Board Replacement)

    Service Procedure F2 (Analog Board Replacement) 1. Before replacing an Analog board, reset the unit by turning the power OFF and ON while holding down the backspace key. If this does not fix the problem, continue. SR785 Dynamic Signal Analyzer Service Guide...

  • Page 79: Service Procedure F3 (Checking The Analog Inputs)

    Pull off the small shield at the front using the finger hole. Remove the correct Analog board by using the card ejectors to release the board and pull the board up and out. Service Guide SR785 Dynamic Signal Analyzer...

  • Page 80: Service Procedure F4 (Checking The Amplitude)

    1. Check the amplitude accuracy by following the procedure outlined in Performance Test 4 (Amplitude Accuracy and Flatness) in Chapter 6 of the SR785 Operating Manual. If the test passes, then check the signal source in question. If the test fails, follow Procedure F2 to replace an Analog board.

  • Page 81: Service Procedure F6 (Checking The Source)

    1. Before replacing a memory module, reset the unit by turning the power OFF and ON while holding down the backspace key. If this does not fix the problem, continue. Turn the power OFF. Remove the power cord from the power entry module. Service Guide SR785 Dynamic Signal Analyzer...

  • Page 82: Service Procedure G1 (Replacing The Disk Drive)

    DRAM module must have its identification pin(s) grounded in order to work in the SR785. These pins are standard in all modules but may not be connected in modules not supplied by SRS. Check the data sheet for the module to ensure that the correct ID pins are connected.
  • Page 83 12. Replace the top lid and refasten the eight lid screws. 13. Replace the power cord. Reset the unit by turning the power ON while holding down the backspace key. Run the Disk test in the [System]<Diagnostics> menu. Service Guide SR785 Dynamic Signal Analyzer...

  • Page 84: Service Procedure J1 (Adjusting The Dc Offset And Cmr)

    5. The five adjustment pots are shown in Figure 8-3. Do not make any other adjustments! Output Offset Analog Board High Gain CMR High Gain Offset Low Gain Offset Low Gain CMR Front Figure 8-3 Analog Adjustments SR785 Dynamic Signal Analyzer Service Guide...
  • Page 85 -70 dBV and -80 dBV is less than -70 dBV) then proceed to the next step. If the reading is greater than -70 dBV, adjust the High Gain Offset pot to minimize the marker reading (see Fig 8-3). Service Guide SR785 Dynamic Signal Analyzer...
  • Page 86 [-] [2] [Enter] [Auto Scale A] [Auto Scale B] Use the knob to move the marker to 1.024 kHz. The amplitude should be -6 dBV. [Marker Ref] {Marker now reads relative to the signal amplitude} SR785 Dynamic Signal Analyzer Service Guide...
  • Page 87 (Ch2) A input. This shorts the input to ground so the analyzer’s own DC offset is measured. [Input] <Input Config> <Channel> Select (Ch1)(Ch2) [Enter] <Ch1 Input Range> (<Ch2 Input Range>) [-] [5] [0] [Enter] Service Guide SR785 Dynamic Signal Analyzer...
  • Page 88 19. Reset the unit by turning the power ON while holding down the backspace key. If the DC offset or Common Mode Rejection are still a problem, repeat this procedure one more time. Otherwise, follow Procedure F2 to replace the Analog board. SR785 Dynamic Signal Analyzer Service Guide...

  • Page 89: Demo Filter

    Chapter 4 Parts Lists This chapter lists the components on the major circuit assemblies in the SR785. The schematics for each board are shown in Chapter 5. In This Chapter CPU Board Parts List Video/IO Board Parts List Power Supply Board Parts List...
  • Page 90 Parts Lists SR785 Dynamic Signal Analyzer Service Guide...

  • Page 91: Cpu Board Parts List

    .01U AXIAL Capacitor, Ceramic, 50V,+80/-20% Z5U AX C 939 5-00262-548 .01U AXIAL Capacitor, Ceramic, 50V,+80/-20% Z5U AX C 950 5-00100-517 2.2U Capacitor, Tantalum, 35V, 20%, Rad C 951 5-00100-517 2.2U Capacitor, Tantalum, 35V, 20%, Rad Service Guide SR785 Dynamic Signal Analyzer...
  • Page 92 Socket, THRU-HOLE SO305 1-00156-150 32 PIN 600 MIL Socket, THRU-HOLE SO306 1-00156-150 32 PIN 600 MIL Socket, THRU-HOLE SO801 1-00156-150 32 PIN 600 MIL Socket, THRU-HOLE SO802 1-00156-150 32 PIN 600 MIL Socket, THRU-HOLE SR785 Dynamic Signal Analyzer Service Guide...
  • Page 93 Integrated Circuit (Thru-hole Pkg) U 703 3-00046-340 74HC374 Integrated Circuit (Thru-hole Pkg) U 704 3-00263-340 DS75451N Integrated Circuit (Thru-hole Pkg) U 705 3-00039-340 74HC14 Integrated Circuit (Thru-hole Pkg) 0-00089-033 4" 0-00373-000 CARD EJECTOR Hardware, Misc. Service Guide SR785 Dynamic Signal Analyzer...

  • Page 94: Video/Io Board Parts List

    2.2U Capacitor, Tantalum, 35V, 20%, Rad C 1453 5-00100-517 2.2U Capacitor, Tantalum, 35V, 20%, Rad C 1454 5-00100-517 2.2U Capacitor, Tantalum, 35V, 20%, Rad J 1401 1-00236-109 120 PIN RT ANGL DIN Connector, Male SR785 Dynamic Signal Analyzer Service Guide...
  • Page 95 Integrated Circuit (Thru-hole Pkg) U 1004 3-00585-340 74ACT573 Integrated Circuit (Thru-hole Pkg) U 1005 3-00585-340 74ACT573 Integrated Circuit (Thru-hole Pkg) U 1006 3-00551-341 128KX8-70 STATIC RAM, I.C. U 1007 3-00551-341 128KX8-70 STATIC RAM, I.C. Service Guide SR785 Dynamic Signal Analyzer...
  • Page 96 Integrated Circuit (Thru-hole Pkg) U 1401 3-00342-340 74ALS138 Integrated Circuit (Thru-hole Pkg) U 1402 3-00342-340 74ALS138 Integrated Circuit (Thru-hole Pkg) X 1201 6-00068-620 24.000 MHZ Crystal X 1301 6-00037-620 3.6864 MHZ Crystal 0-00373-000 CARD EJECTOR Hardware, Misc. SR785 Dynamic Signal Analyzer Service Guide...

  • Page 97: Power Supply Board Parts List

    5 PIN, WHITE Header, Amp, MTA-156 1-00114-116 10 PIN, WHITE Header, Amp, MTA-156 4-00244-421 10KX4 Res. Network, SIP, 1/4W,2% (Isolated) 7-00526-701 SR780-P/S Printed Circuit Board R 10 4-00618-402 2.2K Resistor, Carbon Comp, 1/2W, 5% Service Guide SR785 Dynamic Signal Analyzer...
  • Page 98 0-00316-003 PLTFM-28 Insulators 0-00373-000 CARD EJECTOR Hardware, Misc. 0-00509-000 60MM 12V Hardware, Misc. 1-00002-113 10 PIN,18AWG/OR Connector, Amp, MTA-156 1-00033-113 5 PIN, 18AWG/OR Connector, Amp, MTA-156 6-00179-615 MAP55-4000 Power Supply 7-00541-720 SR780-27 Fabricated Part SR785 Dynamic Signal Analyzer Service Guide...

  • Page 99: System Backplane Parts List

    3 PIN, WHITE Header, Amp, MTA-156 JP22A 1-00272-130 34 PIN DI Connector, Male JP23A 1-00152-116 11 PIN, WHITE Header, Amp, MTA-156 JP24A 1-00250-116 2 PIN, WHITE Header, Amp, MTA-156 Z 0A 6-00076-600 2" SPKR Misc. Components Service Guide SR785 Dynamic Signal Analyzer...

  • Page 100: Disk Card Parts List

    96 PIN RT ANGLE DIN Connector, Male JP2B 1-00272-130 34 PIN DI Connector, Male JP3B 1-00116-130 4 PIN DI DISK Connector, Male JP4B 1-00113-100 DIN 5 Connector, Misc. Z 0B 8-00034-850 FLOPPY Disk Drive SR785 Dynamic Signal Analyzer Service Guide...

  • Page 101: Dsp Board Parts List

    Cap, Monolythic Ceramic, 50V, 20%, Z5U C 577 5-00023-529 Cap, Monolythic Ceramic, 50V, 20%, Z5U C 601 5-00134-529 100P Cap, Monolythic Ceramic, 50V, 20%, Z5U C 602 5-00200-532 470P Capacitor, Ceramic Disc, 50V, 10% NPO Service Guide SR785 Dynamic Signal Analyzer...
  • Page 102 Capacitor, Ceramic, 50V,+80/-20% Z5U AX C 934 5-00225-548 .1U AXIAL Capacitor, Ceramic, 50V,+80/-20% Z5U AX C 935 5-00225-548 .1U AXIAL Capacitor, Ceramic, 50V,+80/-20% Z5U AX C 936 5-00225-548 .1U AXIAL Capacitor, Ceramic, 50V,+80/-20% Z5U AX SR785 Dynamic Signal Analyzer Service Guide...
  • Page 103 Capacitor, Ceramic, 50V,+80/-20% Z5U AX C 991 5-00225-548 .1U AXIAL Capacitor, Ceramic, 50V,+80/-20% Z5U AX C 992 5-00225-548 .1U AXIAL Capacitor, Ceramic, 50V,+80/-20% Z5U AX C 993 5-00225-548 .1U AXIAL Capacitor, Ceramic, 50V,+80/-20% Z5U AX Service Guide SR785 Dynamic Signal Analyzer...
  • Page 104 0-00001-000 WIRE Hardware, Misc. R 112 0-00001-000 WIRE Hardware, Misc. R 113 0-00001-000 WIRE Hardware, Misc. R 114 0-00001-000 WIRE Hardware, Misc. R 115 0-00001-000 WIRE Hardware, Misc. R 116 0-00001-000 WIRE Hardware, Misc. SR785 Dynamic Signal Analyzer Service Guide...
  • Page 105 R 623 4-00032-401 100K Resistor, Carbon Film, 1/4W, 5% R 624 4-00034-401 Resistor, Carbon Film, 1/4W, 5% R 625 4-00045-401 2.0K Resistor, Carbon Film, 1/4W, 5% R 626 4-00062-401 Resistor, Carbon Film, 1/4W, 5% Service Guide SR785 Dynamic Signal Analyzer...
  • Page 106 GAL/PAL, I.C. U 302 3-00597-340 CY7C433-25 Integrated Circuit (Thru-hole Pkg) U 303 3-00597-340 CY7C433-25 Integrated Circuit (Thru-hole Pkg) U 304 3-00597-340 CY7C433-25 Integrated Circuit (Thru-hole Pkg) U 401 3-00265-340 74HC595 Integrated Circuit (Thru-hole Pkg) SR785 Dynamic Signal Analyzer Service Guide...
  • Page 107 GAL/PAL, I.C. U 716 3-00584-340 74ACT574 Integrated Circuit (Thru-hole Pkg) U 720 3-00274-340 74AC74 Integrated Circuit (Thru-hole Pkg) U 721 3-00055-340 74LS74 Integrated Circuit (Thru-hole Pkg) U 722 3-00055-340 74LS74 Integrated Circuit (Thru-hole Pkg) Service Guide SR785 Dynamic Signal Analyzer...
  • Page 108 Heat Sinks 0-00043-011 4-40 KEP Nut, Kep 0-00209-021 4-40X3/8PP Screw, Panhead Phillips 0-00231-043 #4 SHOULDER Washer, nylon 0-00243-003 TO-220 Insulators 0-00341-010 2-56 HEX Nut, Hex 0-00373-000 CARD EJECTOR Hardware, Misc. 0-00728-021 2-56X1/2PP Screw, Panhead Phillips SR785 Dynamic Signal Analyzer Service Guide...

  • Page 109: Analog Input Board Parts List

    Parts Lists 4-21 Analog Input Board Parts List This section covers schematics A780-1 through A780-7 in Chapter 5. The SR785 uses two of these boards. Analog Input Board Assembly Ref No. SRS Part No. Value Component Description C 101 5-00060-512 1.0U...
  • Page 110 5-00100-517 2.2U Capacitor, Tantalum, 35V, 20%, Rad C 391 5-00100-517 2.2U Capacitor, Tantalum, 35V, 20%, Rad C 394 5-00100-517 2.2U Capacitor, Tantalum, 35V, 20%, Rad C 395 5-00100-517 2.2U Capacitor, Tantalum, 35V, 20%, Rad SR785 Dynamic Signal Analyzer Service Guide...
  • Page 111 D 101 3-00004-301 1N4148 Diode D 102 3-00004-301 1N4148 Diode D 103 3-00004-301 1N4148 Diode D 104 3-00004-301 1N4148 Diode D 105 3-00004-301 1N4148 Diode D 106 3-00004-301 1N4148 Diode D 107 3-00004-301 1N4148 Diode Service Guide SR785 Dynamic Signal Analyzer...
  • Page 112 Resistor, Carbon Film, 1/4W, 5% R 103 4-00593-408 965.0K Resistor, Metal Film, 1/8W, 0.1%, 25ppm R 104 4-00515-407 31.6K Resistor, Metal Film, 1/8W, 1%, 50PPM R 105 4-00593-408 965.0K Resistor, Metal Film, 1/8W, 0.1%, 25ppm SR785 Dynamic Signal Analyzer Service Guide...
  • Page 113 Resistor, Metal Film, 1/8W, 1%, 50PPM R 213 4-00873-407 Resistor, Metal Film, 1/8W, 1%, 50PPM R 214 4-00144-407 Resistor, Metal Film, 1/8W, 1%, 50PPM R 215 4-00874-407 84.5 Resistor, Metal Film, 1/8W, 1%, 50PPM Service Guide SR785 Dynamic Signal Analyzer...
  • Page 114 Resistor, Metal Film, 1/8W, 1%, 50PPM R 275 4-00748-408 2.000K Resistor, Metal Film, 1/8W, 0.1%, 25ppm R 276 4-00748-408 2.000K Resistor, Metal Film, 1/8W, 0.1%, 25ppm R 277 4-00178-407 3.83K Resistor, Metal Film, 1/8W, 1%, 50PPM SR785 Dynamic Signal Analyzer Service Guide...
  • Page 115 Resistor, Metal Film, 1/8W, 1%, 50PPM R 392 4-00158-407 2.00K Resistor, Metal Film, 1/8W, 1%, 50PPM R 393 4-00738-407 Resistor, Metal Film, 1/8W, 1%, 50PPM R 394 4-00696-407 43.2K Resistor, Metal Film, 1/8W, 1%, 50PPM Service Guide SR785 Dynamic Signal Analyzer...
  • Page 116 1-00143-101 TEST JACK Vertical Test Jack TP522 1-00143-101 TEST JACK Vertical Test Jack TP531 1-00143-101 TEST JACK Vertical Test Jack TP532 1-00143-101 TEST JACK Vertical Test Jack TP541 1-00143-101 TEST JACK Vertical Test Jack SR785 Dynamic Signal Analyzer Service Guide...
  • Page 117 Integrated Circuit (Thru-hole Pkg) U 551 3-00346-329 7812 Voltage Reg., TO-220 (TAB) Package U 601 3-00265-340 74HC595 Integrated Circuit (Thru-hole Pkg) U 602 3-00265-340 74HC595 Integrated Circuit (Thru-hole Pkg) U 603 3-00265-340 74HC595 Integrated Circuit (Thru-hole Pkg) Service Guide SR785 Dynamic Signal Analyzer...
  • Page 118 78L05 Transistor, TO-92 Package 0-00012-007 TO-220 Heat Sinks 0-00043-011 4-40 KEP Nut, Kep 0-00209-021 4-40X3/8PP Screw, Panhead Phillips 0-00231-043 #4 SHOULDER Washer, nylon 0-00243-003 TO-220 Insulators 0-00373-000 CARD EJECTOR Hardware, Misc. 0-00516-042 Washer, lock SR785 Dynamic Signal Analyzer Service Guide...

  • Page 119: Analyzer Backplane Parts List

    PC1C 7-00797-701 SR785 BACKPLANE Printed Circuit Board R 1A 4-00772-402 Resistor, Carbon Comp, 1/2W, 5% R 1B 4-00098-401 Resistor, Carbon Film, 1/4W, 5% 0-00011-057 GROMMET Grommet 0-00014-002 Power_Entry Hardware 0-00043-011 4-40 KEP Nut, Kep Service Guide SR785 Dynamic Signal Analyzer...
  • Page 120 Wire, #18 UL1015 Strip 3/8 x 3/8 No Tin 0-00525-050 8-1/4" #18 Wire #18 UL1007 Stripped 3/8x3/8 No Tin 0-00527-050 13" #18 Wire #18 UL1007 Stripped 3/8x3/8 No Tin 0-00536-032 31894 Termination 0-00598-031 4-40X1-3/8 M/F Standoff SR785 Dynamic Signal Analyzer Service Guide...
  • Page 121 SR780-44 Machined Part 7-00674-721 SR780-46 Machined Part 7-00675-721 SR780-47 Machined Part 7-00723-720 SR780-48 Fabricated Part 7-00800-709 SR785 Lexan Overlay 8-00045-840 9" Z-AXIS CRT Display 9-00267-917 GENERIC Product Labels 9-00815-924 DBL-SIDED 1/2" Tape, All types Service Guide SR785 Dynamic Signal Analyzer...

  • Page 122: Demo Filter Board Parts List

    Printed Circuit Board 4-00600-407 15.8K Resistor, Metal Film, 1/8W, 1%, 50PPM 4-00600-407 15.8K Resistor, Metal Film, 1/8W, 1%, 50PPM 4-00303-407 7.87K Resistor, Metal Film, 1/8W, 1%, 50PPM 0-00196-052 1-1/2"X#22 Wire #22 UL1007 1-00003-120 Connector, BNC SR785 Dynamic Signal Analyzer Service Guide...

  • Page 123: Miscellaneous Parts List

    SIMM (Dynamic Ram) 3-00613-350 32MB 8X32-60 2K SIMM (Dynamic Ram) 7-00405-720 SR770-11 Fabricated Part 7-00542-720 SR780-8 Fabricated Part 7-00543-720 SR780-9 Fabricated Part 7-00548-720 SR780-15 Fabricated Part 7-00620-720 SR780-26 Fabricated Part 7-00631-720 SR780-25 Fabricated Part Service Guide SR785 Dynamic Signal Analyzer...

  • Page 124: Schematic Diagrams

    Chapter 5 Schematic Diagrams In This Chapter Assembly Board # Schematic # CPU Board 7-00522 MCPU-1 through MCPU-9 Video/IO Board 7-00523 MVID-10 through MVID-14 Power Supply 7-00526 MPWR-1 through MPWR-2 System Backplane 7-00524 MBKPL-20 through MBKPL-23 Disk Card 7-00626 MBKPL-24 Keypad Board 7-00628 MKEY-1...
  • Page 125 Schematic Diagrams SR780 Network Signal Analyzer Service Guide...

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