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Harris Gates One 994 9202 002 Technical Manual

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T.M. No. 888-2314-001
©
Copyright 1990, 1991, 1992, 1994, 1995, 1996, 1998, 1999,
2000, 2001, 2002
Harris Corporation
All rights reserved
GATES ONE - 994 9202 002
GATES TWO - 994 9203 002
GATES FIVE (1-PHASE) - 994 9204 002
GATES FIVE (3-PHASE) - 994 9205 002
TECHNICAL MANUAL
GATES Series™
AM TRANSMITTERS
Printed: 1990
Rev. AF: 06-21-02

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  • Page 1 GATES FIVE (1-PHASE) - 994 9204 002 GATES FIVE (3-PHASE) - 994 9205 002 T.M. No. 888-2314-001 Printed: 1990 © Copyright 1990, 1991, 1992, 1994, 1995, 1996, 1998, 1999, 2000, 2001, 2002 Rev. AF: 06-21-02 Harris Corporation All rights reserved...
  • Page 2 (217/221-7096). Replaceable Parts Service Replacement parts are available 24 hours a day, seven days a week from the HARRIS Service Parts Department. Telephone 217/222-8200 to contact the service parts department or address correspondence to Service Parts Department, HARRIS CORPORATION, Broad- cast Systems Division, P.O.
  • Page 3 MANUAL REVISION HISTORY GATES Series™ AM Transmitters 888-2314-xxx Rev. Pages Affected Date April 1990 None Replaced the following pages: Title Page, v, vii, 2-1 thru 2-6, 3-3, 3-4, 4-3, 4-4, 5-1 thru 5-6, J-3, & J-4 Added MRH-1/MRH-2 Aug. 1990 None Replaced the following pages: Title Page, v, 3-5, 3-6, 4-1 thru 4-4, A-1, B-1, B-2, C-2, E-3, F-1 thru F-3, G-1 thru G-4, J-1, J-2, J-3, J-4, J-9 thru J-11, &...
  • Page 5 C001 and is not the actual part number for C001. In the ten digit part numbers, if the last three numbers are 000, the item is a part that Harris has purchased and has not manufactured or modified.
  • Page 6 888-2314-001 Rev. X WARNING: Disconnect primary power prior to servicing.
  • Page 7 The installation, operation, maintenance and service of this equipment involves risks both to personnel and equipment, and must be performed only by qualified personnel exercising due care. HARRIS CORPORATION shall not be responsible for injury or damage resulting from improper procedures or from the use of improperly trained or inexperienced personnel performing such tasks.
  • Page 8 888-2314-001 Rev. X WARNING: Disconnect primary power prior to servicing.
  • Page 9 FIRST-AID Personnel engaged in the installation, operation, maintenance or servicing of this equipment are urged to become familiar with first-aid theory and practices. The following information is not intended to be complete first-aid procedures, it is a brief and is only to be used as a reference. It is the duty of all personnel using the equipment to be prepared to give adequate Emergency First Aid and thereby prevent avoidable loss of life.

  • Page 10: Table Of Contents

    TABLE OF CONTENTS SECTION I Power Output Calibration ......3-5 GENERAL INFORMATION Overload Adjustment Procedures ....3-6 Introduction .
  • Page 11 VSWR Trips With High Levels Of Modulation and U1,CR4 ........A-1 High Power.
  • Page 12 Symptom: Imbalance In Output Pulse Widths ..F-2 Controller Supply Voltages ......J-2 Audio Imbalance .

  • Page 13: Introduction

    SECTION I GENERAL INFORMATION Introduction 1.1. Section IV, Troubleshooting, pro- Section E, Output Monitor vides a listing of the protection de- Section F, PDM Generator Scope And Purpose 1.1.1. vices in the transmitter as well as Section G, PDM Amplifier/Pull-Up This technical manual contains the infor- troubleshooting procedures.
  • Page 14 Table 1-1. GATES ONE Specifications POWER OUTPUT: 1000 watts (Rated). Six power levels adjustable between 100-1100 watts. Capable of lower power PSA/PSSA operation. RF FREQUENCY RANGE: 531 kHz through 1705 kHz. Supplied to one frequency as ordered. CARRIER FREQUENCY STABILITY: Crystal control oscillator meets FCC specifications.
  • Page 15 Table 1-2. GATES TWO Specifications POWER OUTPUT: 2500 watts (Rated). Six power levels adjustable between 250-2750 watts. Capable of lower power PSA/PSSA operation. RF FREQUENCY RANGE: 531 kHz through 1705 kHz. Supplied to one frequency as ordered. CARRIER FREQUENCY STABILITY: Crystal control oscillator meets FCC specifications.
  • Page 16 Table 1-3. GATES FIVE Specifications POWER OUTPUT: 5000 watts (Rated). Six power levels adjustable between 500-5600 watts. Capable of lower power PSA/PSSA operation. RF FREQUENCY RANGE: 531 kHz through 1705 kHz. Supplied to one frequency as ordered. CARRIER FREQUENCY STABILITY: Crystal control oscillator meets FCC specifications.

  • Page 17: Introduction

    In ad- anced impedances will result in line-to-line For many years HARRIS engineers have dition to the 28 inch width by 30 inch depth voltage unbalance. recommended that the three phase power...

  • Page 18: Three Phase Delta Distribution Transformers

    The WYE connected system is also con- system. HARRIS offers, as an option, engi- overall transmitter may result. For this rea- sidered a symmetrical form of three phase...

  • Page 19: Printed

    This is important due to numerous high and exit the tower as near to the bottom as that the DC supplies are operated in the desired range. current connections in the transmitter. practical to minimize the lightning voltage Also check that all ribbon cables are prop- potential carried by the coax into your Power Requirements 2.6.1.

  • Page 20: Rf Output Connection

    ter and then sliding the circuit breaker in the AC Power panel and is adjusted to you are nearly ready to put the transmitter panel forward. Terminal board TB1 is MIN. See Note below. into regular operation. The transmitter will located on the floor of the transmitter di- operate properly without the battery, how- NOTE...

  • Page 21: Airflow Sensor Status

    Note: All remote control inputs are activated the cable for the modulation monitor from MITTER AND SHOULD BE USED TO AS- SURE THAT ALL HIGH VOLTAGE HAS by applying a momentary ground connection the base of the transmitter up to the location BEEN REMOVED UNDER FAULT CONDI- to each desired input.

  • Page 22: Modulation Monitor Carrier Level

    Report any the procedure in Section C. t. Adjust the Tuning and Loading controls major discrepancies to the HARRIS k. Confirm that when any of the power ON as necessary to null the Detector Null Service Department.

  • Page 23: Application Of Audio

    the REMOTE position will enable the re- adjustable down to -10dbm. If you desire to Set the remote control unit’s calibration mote control circuits and should be in RE- increase the sensitivity, you may adjust R21 adjustments to match the transmitter’s me- MOTE position for normal operation.
  • Page 24 Figure 2-4. Base of GATES Transmitter CONTROL/INDICATOR FUNCTION Power Transformer A19T1 Main Power Supply transformer for 260 volt dc supply. PDM Pullup Resistors Shield shown covering 250 watt resistor(s) used by PDM Pull-up circuits. Low Voltage Transformer A20T1 Secondary for +20VDC, -20VDC, 24 VAC, and IPA Supply (60/75/90/105/120 Vdc). Table 2-5.
  • Page 25 CONTROL/ INDICATOR FUNCTION Relay K1 Relay K1 is used to apply AC to the high vo ltage transfo rmer through current limiting resistor(s) during the step start sequence. Relay K2 Relay K2 is used to apply AC mains directly t o t h e h i g h vol tage transformer.

  • Page 26: Vswr Detector

    Table 2-7. GATES ONE Typical Readings at 1340kHz Power Output 1000W 800W 600W 400W 200W 100W PA Volts 92.5 46.5 PA Amps 12.5 11.3 PDM Level Supply Voltage Supply Current RF Drive VSWR Detector Null VSWR Detector Null Set Underdrive Set Supply Current Set Supply Voltage Set Battery...
  • Page 27 Table 2-9. GATES FIVE Typical Readings at 920kHz Power Output 5000W 4000W 3000W 2000W 1000W 500W PA Volts 96.0 87.0 76.0 62.0 48.5 37.0 PA Amps 57.5 52.5 46.0 38.5 29.5 22.5 PDM Level Supply Voltage Supply Current 24.1 20.0 15.8 12.0 RF Drive...
  • Page 28 2-12 888-2314-001 Rev. AC: 2/29/00 WARNING: Disconnect primary power prior to servicing.

  • Page 29: Introduction

    SECTION III MAINTENANCE Introduction 3.1. tenance consists of six operations: inspect- pounds. Over-tightening the transistor This section provides preventive mainte- ing, feeling, tightening, cleaning, adjusting, hardware will cause the silicon insulators to nance information and corrective mainte- and painting. curl up on the ends and possibly short nance procedures.

  • Page 30: Pdm Amplifier

    assembly, examine resistors for dirt Be sure to include an inspection of WARNING or signs of overheating. Discolored, the power supply discharge switches cracked, or chipped components indi- located at the bottom of the rear ENSURE ALL POWER IS REMOVED AND N E T WO R K C O M P O N E N TS A R E...
  • Page 31 Figure 3-1. Cabinet Top Figure 3-2. Output Network Removed from Transmitter Rev. AD 888-2314-001 WARNING: Disconnect primary power prior to servicing.

  • Page 32: High Voltage Supply Adjustment

    Figure 3-3. Cabinet Top with Output Network Removed volts depending on the particular needs of Significantly less than this will sacrifice oscilloscope probe across R13 or the the transmitter and frequency. positive peak modulation if operating at or equivalent terminal of any module. The primary of the Low Voltage trans- near the transmitter’s rated power.

  • Page 33: Ipa Tuning

    supply voltage. The transformer secondar- Adjust R31 on the Controller board to the external ammeter on a convenient cali- ies are designated 60/75/90/105/120 Vdc. make the PA Voltmeter read zero. bration level. Moving from the 105 tap to the 90 tap will Adjust A19 R10 (on the floor of the trans- PA Volt Meter Calibration 3.3.9.

  • Page 34: Overload Adjustment Procedures

    Overload Adjustment Procedures 3.3.13. With the actual RF Drive having been VSWR detector to not be nulled when you verified on the PA module(s), the RF Drive bring up RF power. Power Supply Current Overload 3.3.13.1. reading is adjusted so that it reads suffi- Gradually increase the power output, and Check the present Power Supply Current ciently above the Underdrive Set reading at...

  • Page 35: Contactor Control

    SECTION IV TROUBLESHOOTING Introduction Symptom: Transmitter Will 4.1. 4.3. WARNING Not Turn On - None of the This section of the technical manual con- Green LED’s on the Power BEFORE PERFORMING THE FOLLOW- tains overall troubleshooting procedures for Level Switches are Illuminated ING STEP, DISCONNECT ALL POWER the GATES Series™...

  • Page 36: Power Output

    Power Supply Current Over- Symptom: High Voltage Is Pre- 4.6. 4.7.2. sensing LEDS on the front panel, and refer sent, But There Is No Power loads- At Turn On to Section G, Troubleshooting the PDM Output Amplifiers. Supply Short 4.7.2.1. PDM Kill Condition 4.6.1.

  • Page 37: Vswr Trips With High Levels Of Modulation And High Power

    Causes for a PA Volts/PA Isolate the problem further as outlined impedance has changed from the initial tune 4.9. Amps Ratio Change below. If a change in antenna impedance is up or that the transmitter tuning or loading This discussion covers causes which indicated, it may be due to a failed capacitor has changed (either through front panel ad- might not be apparent based on front panel...

  • Page 38: Troubleshooting Am Noise

    100/120Hz if one particular pair is not drawing any ally be above or below the range of the 4.10.3. This is the principle noise frequency of all current. receiver or human hearing. Following are the low level supplies. If 100/120Hz noise some hints on solving various noise prob- is generated in the 3-phase version, you will lems.

  • Page 39: Transmitter Overall

    SECTION V TRANSMITTER OVERALL Introduction 5.1. turned off, the rear panel be opened ap- On the highest positive modulation peaks, This section of the maintenance manual proximately 2 inches and be allowed to the PA voltage may reach the 260 volt level will present the principles of operation for remain in this position for 2 seconds before if the PDM duty cycle reaches 100 percent.
  • Page 40 Figure 5-1. PDM Flow Diagram 888-2314-001 Rev. T: Jan. 1996 WARNING: Disconnect primary power prior to servicing.

  • Page 41: Pdm Loop

    Filters. For further discussion on the opera- The Power Supply Current is metered in is energized, it shorts out step-start resistors tion of the PDM Amplifiers, refer to section the return side of the 260 volt supply. and supplies full AC power to transformer Supply current is less than PA current as a A19T1.
  • Page 42 Figure 5-2. PDM Loop 888-2314-001 Rev. T: Jan. 1996 WARNING: Disconnect primary power prior to servicing.
  • Page 43 Figure 5-3. RF Flow Rev. T: Jan. 1996 888-2314-001 WARNING: Disconnect primary power prior to servicing.

  • Page 44: Description

    Low Voltage Power Supply and operating voltage in case of a high voltage 5.3.10. Since this is a low voltage power supply, IPA Power Supply transient coming in the AC power line. there are no interlocks on the rear panel It is recommended that spare MOV’s of controlling this power supply.

  • Page 45: Parts List

    Section VI Parts List Introduction This section of the technical manual contains a list of the replaceable parts for the GATES Series™ AM TRANSMITTER. Replaceable Parts List Index Table 6-1. GATES ONE ......994 9202 002 Table 6-2.
  • Page 46 Table 6-1. GATES ONE - 994 9202 002 Harris PN Description QTY UM Reference Designators (N) 494 0378 000..CHOKE 0.33UH 10% 780MA ... . 0.0 EA A01L14 A01L15 A01L24 A01L25 A01L34 A01L35 A01L44 A01L45 FREQ 494 0399 000.
  • Page 47 994 9239 001 ..R-PK-GATES ONE ....0.0 EA Table 6-2. BASIC GATES ONE - 994 9202 001 Harris PN Description...
  • Page 48 994 7784 003..COIL CLIP 1/2 RIBBON ....1.0 EA Table 6-4. GATES ONE CONV PARTS - 992 8158 001 Harris PN Description...
  • Page 49 Table 6-5. GATES TWO - 994 9203 002 Harris PN Description QTY UM Reference Designators (N) 494 0378 000 ..CHOKE 0.33UH 10% 780MA ... 0.0 EA...
  • Page 50 994 9240 001..R-PK-GATES TWO ....0.0 EA Table 6-6. BASIC GATES TWO - 994 9203 001 Harris PN Description...
  • Page 51 994 7784 003 ..COIL CLIP 1/2 RIBBON....1.0 EA Table 6-8. GATES TWO CONV PARTS - 992 8159 001 Harris PN Description...
  • Page 52 992 9714 001..PWA, PA MODULE ....1.0 EA 999 2621 001..HARDWARE LIST, GATES TWO CONV. . . 1.0 EA Table 6-9. GATES FIVE, 1PH - 994 9204 002 Harris PN Description QTY UM Reference Designators (M) 494 0378 000.
  • Page 53 994 9241 001 ..R-PK-GATES FIVE ....0.0 EA Table 6-10. BASIC GATES FIVE 1PH - 994 9204 001 Harris PN Description...
  • Page 54 994 7784 003..COIL CLIP 1/2 RIBBON ....1.0 EA #A21L01 Table 6-11. GATES FIVE 1PH CONV PARTS - 992 8160 001 Harris PN Description QTY UM Reference Designators (AZ) 357 0092 000.
  • Page 55 Table 6-12. GATES FIVE 1PH UNIQUE PTS - 992 8291 001 Harris PN Description QTY UM Reference Designators (E) 335 0256 000 ..WASHER, SHOULDER .765 ID ..4.0 EA 335 0257 000 .
  • Page 56 994 9241 001..R-PK-GATES FIVE ....0.0 EA Table 6-14. BASIC GATES FIVE 3PH - 994 9205 001 Harris PN Description...
  • Page 57 358 3123 000 ..STUD, BRS 10-32 X 1-1/2....3.0 EA 384 0705 000 ..RECT 85A 1000V PIV ESD ... . 6.0 EA A19CR1 A19CR2 A19CR3 A19CR4 A19CR5 A19CR6 404 0707 000 .
  • Page 58 Table 6-16. BASIC GATES SERIES XMTR - 992 8143 001 Harris PN Description QTY UM Reference Designators (BK) 026 6010 003..GROMMET STRIP, 0.125 ....0 FT 041 6030 014.
  • Page 59 570 0322 000 ..CNTOR 50A 208/240V 3P....1.0 EA A19K2 604 0061 000 ..SW SPDT 15A 125/250 VAC ... 1.0 EA A19S4 606 0159 000 .
  • Page 60 829 8305 514..STRAP, INTERCONNECT ....1.0 EA 829 8305 544..SHAFT EXTENSION ....1.0 EA 829 8305 570.
  • Page 61 992 9813 001 ..PWA, IPA BOARD....1.0 EA A005 Table 6-17. AIRFLOW SENSOR - 992 9146 001 Harris PN Description QTY UM Reference Designators (J) 358 1929 000 .
  • Page 62 614 0790 000..TERM MODULE,1C PC MTG 236 ..3.0 EA #TB001 670 0052 000..BUZZER, PIEZO 3-20VDC....1.0 EA LS001 843 5400 041.

  • Page 63: Section A

    SECTION A OSCILLATOR (A16) Principles Of Operation Replacement/Alignment Q1,Q2,CR1 A.1. A.2. A.3.1.3. Using an oscilloscope, check the signals The oscillator is the frequency determin- Frequency Adjustment A.2.1. at Q1 and Q2 per the schematic. Frequency ing source. The crystal oscillator stage is a A16C1 trims the carrier frequency at least of the signals at Q1 and Q2 should be 2 or voltage stabilized Pierce circuit operating at...
  • Page 64 Figure A-3 Upper Trace - E6, 2-3Vp-p Lower Trace - U2-7, 14Vp-p PWA, OSCILLATOR - 992 8146 001 Harris PN Description QTY UM Reference Designators (R) 335 0254 000 . . WASHER, TEFLON #4... 2.0 EA #U003 380 0083 000 .
  • Page 65 516 0387 000 . . CAP .47 UF 10V ....1.0 EA C004 516 0453 000 . . CAP .1UF 100V 20% X7R ..4.0 EA C008 C014 C016 C020 520 0439 000 .
  • Page 66 Figure A-4. Oscillator Board A16 Controls & Indicators Table A-1. Oscillator Board A16, Controls & Indicators Frequency Adjustment A16C1 Adjusts the carrier frequency of approximately +/-20 Hz. Frequency Adjustment A16C22 Adjusts the carrier frequency of Y2 approximately +/-20 Hz. Switch S1 Selects Y1 or Y2 crystal.

  • Page 67: Section B

    SECTION B IPA (A5) Principles of Operation Ohmmeter Testing the IPA B.1. B.3.1. rect waveform. Proper drive level should be The IPA Board consists of a class D bridge 26-32 volts peak to peak on all eight inputs amplifier using high power MOSFET tran- of each PA module A1, A2, A3, and A4, with WARNING sistors.

  • Page 68: Testing Mosfet's

    they walk across the carpet. This static test. A Simpson 260, which uses a 9V bat- Connect the positive lead of the ohmmeter charge will eventually have to be dis- tery on the Rx10k scale works quite well. to the source of the transistor. Momentarily charged.
  • Page 69 Table B-1. IPA Board A5 & IPA Power Splitter Board A26A1, Controls & Indicators Rev. AE 03-05-2002 888-2314-001 WARNING: Disconnect primary power prior to servicing.
  • Page 70 PWA, IPA BOARD - 992 9813 001 Harris PN Description QTY UM Reference Designators (F) 000 0000 003 . . FREQUENCY DETERMINED PART 0.0 EA JUMPER 254 0002 000 . . WIRE, BUS CU 20AWG ..0.0 FT 336 0264 000 .

  • Page 71: Section C

    SECTION C POWER AMPLIFIER A1 through A4 Principles of Operation C.1. Blown fuses are detected via diodes CR11 Using an ohmmeter on the Rx1 scale, Each PA board consists of four bridge and CR12. check the fuses on the PA module. Remove class D amplifiers with four power MOS- ALL EIGHT fuses and discard any open PA Toroids...

  • Page 72: Handling Mosfet's

    WARNING NEVER ATTEMPT TO OPERATE THE TRANSMITTER WITH ANY PA TRANSIS- TORS REMOVED. IF REPLACEMENTS ARE NOT AVAILABLE, IT IS NECESSARY TO LEAVE THE SHORTED ONES IN CIR- CUIT. THIS WILL KEEP THE TOROIDAL COMBINING IN TACT, AND WILL NOT IM- PAIR OPERATION OF THE TRANSMITTER AT A REDUCED POWER LEVEL.
  • Page 73 however the mounting terminals for R13 are always in place. The voltage across R13 should be 26-32 volts peak-to-peak. Adjust the horizontal vernier of the oscil- loscope so that one full RF cycle occupies a certain number of divisions on the oscil- loscope.
  • Page 74 Figure C-3 Upper Trace - PA Output Amplitude Equal to PA Voltage Lower Trace - PA Inputs, 26-32Vp-p PWA, PA MODULE - 992 9714 001 Harris PN Description QTY UM Reference Designators (H) 000 0000 010 . . B/M NOTE: ....0.0 EA...
  • Page 75 #E011 #E012 #E021 #E022 #E031 #E032 #E041 #E042 E1 AND BELOW F11 358 3032 000 . . STANDOFF 4-40 1/2L 1/4HEX..10.0 EA E001 E001A E011 E012 E021 E022 E031 E032 E041 E042 380 0681 000 . . XSTR IRFP350 ESD ... . 16.0 EA Q011 Q012 Q013 Q014 Q021 Q022 Q023 Q024 Q031 Q032 Q033 Q034 Q041 Q042 Q043 Q044 382 0355 000 .
  • Page 76 888-2314-001 Rev. AE: 03-05-2002 WARNING: Disconnect primary power prior to servicing.

  • Page 77: Section D

    SECTION D OUTPUT NETWORK Principles of Operation Bandpass Filter L2-C2 D.1. D.2.2.2. mum inductance, which is with their taps at Disconnect the strap which connects to The Output Network is a Butterworth the top of the coils. the input side (towards rear of transmitter) bandpass filter which passes the carrier fre- As the coils are then adjusted downward of A21 C3.

  • Page 78: L1 Tap

    L1 Tap PA module operates into is a complex im- D.2.2.5. L1 sets the reactive component that the PA pedance, with the resistive part being ap- modules should operate into. The PA nor- proximately 7 ohms per PA module. mally sees a negative reactance with a value Sliding the tap towards the ground end of depending on frequency and performance L2 will result in heavier loading of the PA.

  • Page 79: Section E

    SECTION E OUTPUT MONITOR (A18) Principles of Operation E.1. rheostats in circuit to affect the sample volt- monitor. If you are not connecting a modu- The Output Monitor board provides the age so that the monitor sample may be the lation monitor to J3, then leave rheostats VSWR detection, the dc voltage sample for same for all six power levels.
  • Page 80 Figure E-1. Output Monitor Board 888-2314-001 Rev.AE: 03-05-2002 WARNING: Disconnect primary power prior to servicing.
  • Page 81 OUTPUT MONITOR - 992 8144 001 Harris PN Description QTY UM Reference Designators (N) 000 0000 000 . . SHADOW&PAPER B/M COMPARED0.0 EA C009 C010 L002 L003 L004 254 0001 000 . . WIRE, BUS CU 22AWG ..1 FT 335 0001 000 .
  • Page 82 888-2314-001 Rev.AE: 03-05-2002 WARNING: Disconnect primary power prior to servicing.

  • Page 83: Section F

    SECTION F PDM GENERATOR (A15) Principles Of Operation F.1. comparator action at different halves of the PA voltage or power output is observed on The purpose of the PDM Generator board triangle wave cycle. the front panel meters. is to produce the pulse width modulated Since one trangle wave is 90 degrees out Operate the transmitter at a normal power signals which set up the carrier power and...

  • Page 84: Symptom: Imbalance In Output Pulse Widths

    U10, U7 and U8 are suspect. These are the integrator amplifiers which take a square wave inputs, and convert them to triangle waves. If the square waves are not getting to integrator amplifiers U7 and U8, use the oscilloscope to check the output of the 240 kHz oscillator at U11-3.

  • Page 85: Symptom: Only One Output High

    Symptom: Two Outputs Are High put(s) of the PDM generator are at fault by F.3.5. If the PDM Level is okay, the problem If the signals at R45 and R62 are both connecting a voltmeter or oscilloscope to could be caused by U1, U2, U12 or U15 on high, U1 most likely has failed.
  • Page 86 PDM GENERATOR - 992 8145 001 Harris PN Description QTY UM Reference Designators (Y) 380 0125 000 . . XSTR, NPN 2N4401 ESD ..3.0 EA Q003 Q004 Q006 380 0126 000 . . XSTR, PNP 2N4403 ESD ..1.0 EA Q005 382 0184 000 .
  • Page 87 548 2400 285 . . RES 750 OHM 1/2W 1% ..4.0 EA R045 R046 R062 R063 548 2400 309 . . RES 1.21K OHM 1/2W 1%..1.0 EA R099 548 2400 326 .
  • Page 88 888-2314-001 Rev.AE: 03-05-2002 WARNING: Disconnect primary power prior to servicing.

  • Page 89: Section G

    SECTION G PDM AMPLIFIER/PULL-UP (A6-A9) Principles of Operation G.1. Transistors Q19 and Q20 are in parallel the PDM Amplifier and reduces low power and will share the current from the PDM distortion. PDM Amplifier G.1.1. filter. When the incoming PDM signal is The purpose of the PDM amplifier is to Maintenance G.2.

  • Page 90: In-Circuit Ohmmetering The Pdm Amp Module

    CAUTION ENSURE THAT THERMAL COMPOUND IS APPLIED TO PLATES OF THE PDM AMPLI- FIER BOARDS BEFORE THEY ARE IN- STALLED ON HEAT SINKS AND THAT HARD- WARE SECURING BOARD TO HEAT SINK IS PROPERLY TORQUED TO 6-INCH POUNDS. ALSO INSURE NO BURRS OR DIRT PARTI- CLES ARE ON THE MATING SURFACES, AS THESE WILL IMPAIR THE HEAT SINKING.
  • Page 91 Figure G-2. PDM Amplifiers, A6 thru A9 Table G-2. PDM Amplifiers, A6 thru A9 Controls and Indicators Controls and Indicators A6F1 (A6 located at rear of transmitter) Protects +20 volt supply from over current surges on PDM Amp Board A6. A7F1 (A7 located at rear of transmitter) Protects +20 volt supply from over current surges on PDM Amp Board A7.

  • Page 92: Checking Gate Drive

    Checking Gate Drive G.2.3.1. charge will eventually have to be dis- “off” by charging and discharging the gate Apply low voltage only to the transmitter. charged. Discharging to the MOSFET of the MOSFET. Make sure the transmitter is off by depress- could damage the MOSFET.
  • Page 93 * PDM AMP BOARD * - 992 5872 005 Harris PN Description QTY UM Reference Designators (AC) 296 0259 000 . . TUBING TEFLON 18 AWG ..0.0 FT #CR1 304 0087 000 . . NUT, HEX 4-40 ....3.0 EA #CR1 STUD #E11 #E31 308 0003 000 .
  • Page 94 * PDM PULL UP BOARD * - 992 5872 006 HARRIS P/N DESCRIPTION QTY/UM REF. SYMBOLS/EXPLANATIONS 384 0686 000 . . DIODE, DSR-3400X ESD ..2.0 EA CR001 CR002 384 0783 000 . . DIODE MR854 ESD ... . 2.0 EA CR003 CR004 398 0402 000 .

  • Page 95: Section H

    60 kHz component, but yet remain a two L-C sections. Part of the second capaci- high impedance to the audio component. PWA, PDM FILTER ESD SAFE - 992 5874 009 (GATES TWO/FIVE) HARRIS P/N DESCRIPTION QTY/UM REF. SYMBOLS/EXPLANATIONS 335 0037 000 .
  • Page 96 888-2314-001 Rev. AA: 8/18/1999 WARNING: Disconnect primary power prior to servicing.

  • Page 97: Section J

    SECTION J CONTROLLER BOARD (A12) Principles of Operation J.1. the power level indicator LED in the LOW U14 and U15 are Up/Down counters The Controller board contains the cir- switch, a source voltage for the power level which provide a 8 bit digital output which cuitry for controlling the primary contac- control pot R54, and provides an output to changes as the Fine Power circuit is oper-...

  • Page 98: Other Fault Detection

    toroutput goes HIGH, U25 gets clocked. As paring the PDM sample voltage against a WARNING a result, U25 pin 8 goes low. power level reference (PDMREF) provided TURN OFF TRANSMITTER AND DIS- After a time period determined by R34, by U20. If the sample voltage goes above CHARGE HIGH VOLTAGE BEFORE PRO- R35, and C11, the output of U26 follows its the threshold voltage provided by U20, the...

  • Page 99: Power Output Calibration

    Power Output Calibration Failed flip flop circuitry J.2.4. After verifying the actual RF drive to be J.4.1.2. Check the operation of U4, U5, and U6 or Connect the transmitter into a load with in the normal range, modulate the transmit- replace them.
  • Page 100 Chart of Functions U12 CD4048 H I G H p ow er level selection U14* 74C193 Fine Power Up/Down counter U15* 74C193 Fine Power Up/Down counter U16* CD4048 F i n e P ow er U pper Limit detector U17* CD4048 F i n e P ow er Lower Limit detector U18* DA0808...
  • Page 101 CONTROLLER - 992 8147 001 Harris PN Description QTY UM Reference Designators (W) 250 0476 000 . . CABLE ASSY 12C 1.8" 22AWG..1.0 EA P003 354 0309 000 . . TERM SOLDER ....9.0 EA #UNIT 4 5 6 VIS PA COMB 358 2751 000 .
  • Page 102 526 0350 000 . . CAP 3.9UF 35V 10% ... . 1.0 EA C009 526 0351 000 . . CAP 6.8UF 50V 20% ... . 2.0 EA C008 C017 526 0358 000 .

  • Page 103: Section K

    SECTION K INTERFACE BOARD (A24) Principles of Operation K.1. Also included on the Interface board are phase monitor relay (A19K3), then the The Interface Board provides the Audio the remote status transistor packs U2, U3, problem may be on the Interface board. Input, Failsafe, and remote control connec- and U4.
  • Page 104 888-2314-001 Rev.AE: 03-05-2002 WARNING: Disconnect primary power prior to servicing.
  • Page 105 Figure K-1. Interface Board Rev.AE: 03-05-2002 888-2314-001 WARNING: Disconnect primary power prior to servicing.
  • Page 106 INTERFACE BD - 992 8148 001 Harris PN Description QTY UM Reference Designators (N) 000 0000 002 . . APPEARS ON A HIGHER LEVEL . . 0.0 EA R005 R007 R008 C014 Q001 Q002 CR005 K001 J011 358 2997 000 . . END PLATE,236 TERM MODULE. . 2.0 EA TB001 TB002 380 0678 000 .

  • Page 107: Appendix Ltest Equipment

    APPENDIX L TEST EQUIPMENT Introduction L.1. 1. An oscilloscope with 15 MHz or 4. A noise/distortion meter This appendix contains a list of the test higher bandwidth equipment recommended to perform gen- 2. A VOM with an ohmmeter battery eral maintenance and troubleshooting of the voltage between 3 and 18V 3.
  • Page 108 888-2314-001 WARNING: Disconnect primary power prior to servicing.
  • Page 109 Electrostatic Discharge Control: A Guide To Handling Integrated Circuits Technical Brief January 1994 TB52 This paper discusses methods and materials recommended Relative humidity in the work area should be maintained as for protection of ICs against ESD damage or degradation high as practical.
  • Page 110 Technical Brief 52 Don’ts Don’t allow plastic ‘‘snow or peanut’’ polystyrene foam or other high dielectric materials to come in contact with Don’t allow anyone not grounded to touch devices, loaded devices or loaded sticks or loaded burn-in boards. sticks or loaded burn-in boards. To be grounded they must be standing on a conductive floor mat with conductive heel straps Don’t allow rubber/plastic floor mats in front of static con- attached to footwear or must wear a grounded wrist strap.

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