Ericsson 9D902780G3 Maintenance Manual Download Page 7 | Manualshive

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Ericsson 9D902780G3 Maintenance Manual Download Page 7

PRODUCTION CHANGES & IC DATA

U301
19A704971P9
+5V Regulator

U302 & U601
19A116297P7
Dual Wide Band Op-Amp

U201 and U203
19A705927P11
Silicon Bipolar MMIC

U202
344A3907P1
Silicon Bipolar MMIC

U303
19A704971P7
-5V regulator

U501
344A3070P1
Operational Amplifier

PRODUCTION CHANGES

Changes in the equipment to improve or to simplify circuits are identified by a
"Revision Letter", which is stamped after the model number of the unit. The
revision stamped on the unit includes all previous revisions. Refer to the Parts
List for descriptions of parts affected by these revisions.

REV. A - TRANSMITTER SYNTHESIZER BOARD
19D902779G3,6,7

To correct loading problem on synth IC which could cause failure to lock
on channel.
R707 was 47k ohms (19B800607P473).

REV. B - TRANSMITTER SYNTHESIZER BOARD
19D902779G3, G6-G8

To make new band splits compatible with helical filters. New PWB.
C15 was 0.1

µ

F (19A700004P2).

C16 was 330 pF (19A702061P73).

LBI-38671

6

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Summary of Contents for 9D902780G3

Page 1: ... 1 RF AMPLIFIERS 1 REFERENCE BUFFER AMPLIFIER 1 PRESCALER AND SYNTHESIZER 2 LOOP BUFFER AMPLIFIERS 2 AUDIO FREQUENCY AMPLIFIER 2 VOLTAGE REGULATORS 2 LOGIC CIRCUITS 3 BLOCK DIAGRAM 2 MAINTENANCE 3 TEST PROCEDURE 3 ALIGNMENT PROCEDURE 3 TROUBLESHOOTING 3 PARTS LIST 4 PRODUCTION CHANGES 6 IC DATA 6 OUTLINE DIAGRAM 8 SCHEMATIC DIAGRAM 9 ASSEMBLY DIAGRAM Back Cover Ericsson Inc Private Radio Systems M...

Page 2: ...ors Q801 and Q802 form a buffer stage to drive transistor multiplier Q803 The buffer isolates VCO Q1 from loading effects which could degrade oscillator loaded Q and hence noise performance Transistor multiplier Q803 is tuned to pass the second harmonic of the VCO output and serves as a frequency doubler Tank elements L802 C812 C814 and L803 form a resonant circuit and matching net work to drive r...

Page 3: ...f the audio modulation and the buffered error signal The output of the second buffer U501B is applied to a loop filter consisting of R506 R507 R508 C505 and C506 This filter controls the bandwidth and stability of the synthe sizer loop The UHF transmitter synthesizer has a loop bandwidth of only several Hertz This is very narrow result ing in an excessively long loop acquisition time To speed acqu...

Page 4: ...nput Verify 5 6 Measure Hum and Noise relative to 0 44 kHz average deviation de emphasis on Verify 55dB 7 Measure AF response at 300 Hz 1 kHz ref and 3 kHz de emphasis off Verify within 1 5 dB with respect to 1 kHz reference 8 Verify lock at different frequencies a Lock synthesizer at 380 G8 450 G3 403 G6 425 G7 or 470 G9 MHz Verify LED is off b Lock synthesizer at 385 G8 455 G3 408 5 G6 430 G7 or...

Page 5: ... 50 VDCW temp coef 0 or 30 PPM C C17 19A702061P99 Ceramic 1000 pF or 5 50 VDCW temp coef 0 or 30 PPM C C18 19A705205P2 Tantalum 1 uF 16 VDCW sim to Sprague 293D and C19 C101 19A702061P99 Ceramic 1000 pF or 5 50 VDCW temp coef 0 or 30 PPM C C102 19A705205P2 Tantalum 1 uF 16 VDCW sim to Sprague 293D C103 19A702061P99 Ceramic 1000 pF or 5 50 VDCW temp coef 0 or 30 PPM C C201 19A702061P61 Ceramic 100 ...

Page 6: ...5 1 8 w R211 19B800607P150 Metal film 15 ohms or 5 1 8 w R212 19B800607P331 Metal film 330 ohms or 5 1 8 w and R213 R214 19B800607P150 Metal film 15 ohms or 5 1 8 w SYMBOL PART NO DESCRIPTION R215 19B800607P331 Metal film 330 ohms or 5 1 8 w R216 19B800607P510 Metal film 51 ohms or 5 1 8 w R217 19B800607P220 Metal film 22 ohms or 5 1 8 w R218 19B800607P330 Metal film 33 ohms or 5 1 8 w R219 19B800...

Page 7: ...sion Letter which is stamped after the model number of the unit The revision stamped on the unit includes all previous revisions Refer to the Parts List for descriptions of parts affected by these revisions REV A TRANSMITTER SYNTHESIZER BOARD 19D902779G3 6 7 To correct loading problem on synth IC which could cause failure to lock on channel R707 was 47k ohms 19B800607P473 REV B TRANSMITTER SYNTHES...

Page 8: ...DATA U401 19A149944P201 Dual Modulus Prescaler U402 19B800902P5 Synthesizer U502 19A702705P4 Quad Analog Switch U701 U705 19A703483P302 Quad 2 Input NAND Gate U702 19A703471P120 Address Decoder LBI 38671 7 ...

Page 9: ...OUTLINE DIAGRAM UHF TRANSMITTER SYNTHESIZER BOARD 19D902779G3 G6 G9 SOLDER SIDE COMPONENT SIDE 19D902779 Sh 2 Rev 2 19D903361 Layer 1 4 Rev 0 LBI 38671 8 ...

Page 10: ...SCHEMATIC DIAGRAM UHF TRANSMITTER SYNTHESIZER 19D902780G3 G6 G9 19D903363 Sh 1 Rev 5 LBI 38671 9 ...

Page 11: ...SCHEMATIC DIAGRAM UHF TRANSMITTER SYNTHESIZER 19D902780G3 G6 G9 19D903363 Sh 2 Rev 3 LBI 38671 10 ...

Page 12: ...SCHEMATIC DIAGRAM UHF TRANSMITTER SYNTHESIZER 19D902780G3 G6 G9 19D903363 Sh 3 Rev 2 LBI 38671 11 ...

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