Kenwood TR-7850 Service Manual

QKENWOOD:
SERVICE
Model TR-7850
MANUAL
A product of
TRIO-KENWOOD CORPORATION
17-5, 2-chome, Shibuya, Shibuya-ku, Tokyo 150, Japan
ner fe 7S 7 SS ne A TS AE
TRIO-KENWOOO COMMUNICATIONS, INC.
1111. West Walnut Street, Compton. Califorma, 90220
TRIO-KENWOOO COMMUNICATIONS, GmbrH
0-6374 Steinbach TS. industriestrasse 8A. West Germany
TRIO-KENWOOO(AUSTRALIA)PTY. LTD.
30 Whiting Street. Artarmon. Sydney N.S.W. Australia 2064
VHF FM TRANSCEIVER
USE THIS SERVICE MANUAL
TOGETHER WITH THAT OF TR-7800.
CONTENTS
BLOCK 'DIAGRAM 22th eas ote eer 2
PC BOARD VIEW
FINAL UNIT (X45-1180-10) 0.0.0... eeeceeeeeeeeceeeeeeenes 2
PPO: VST cerita onpectenucul stateside Doel sical elec ianh wots, 3
SEMICONDUCTOR DATA.............ccccsccesesccesecceesscenseees 4
PRD SUS TIVE T Sates casei asics oben viae taledesdileut todo hahadadin 5
SCHEMATIC ABBREVIATION ..............cceceeceeeneeeeeneeeeenes 6
SCHEMATIC DIAGRAM (K)(M) ........ eect etree 7
SCHEMATIC DIAGRAM (W)(T) ..............086 BACK COVER
[General]
Semiconductors .........
Frequency range.........
Frequency synthesizer.
WV Kolo (-
Antenna impedance....
Power requirement.....
Grounding
- Operating temperature
Currentdrain..............
eo ee ete wes eeneses
[Transmitter Section]
RF output power
(at 13.8V DC, 502 load) ..........
Modulation ................
SPECIFICATIONS
Aegaedeayerets MPU 1
ICs 18 (W)(T), 19 (K)(M)
Transistors 58 (W)(T), 60 (K)(M)
FETs 9
Diodes 79 (K)(M)(T), 78 (W)
144.000 to 145.995 MHz (W){(T)
144.000 to 148.995 MHz (K)(M)
Digital control, phase locked VCO
FM (F3)
50 ohms
13.8V DC +15%
Negative
—20°Cto +50°C
0.4A in receive mode with no input
signal 9A in HI transmit mode (Approx.)
Less than 3 mA for memory back up
(from an external power supply
through the BACK UP terminal)
Less than 2 mA for memory back up
(from battery)
175 mm (6-7/8") wide
64 mm (2-1/2") high
220 mm (8-5/8") deep
(projections excluded)
2.2 kg (4.84 Ibs) (approx.)
Bea e wr eraresonee
sewer ereraraee
ay
eee eenereseses
ee ey
ev ere eee revene
ee eee eee aerere
Hi 40 Watts min.
LOW 1 to 15 watts approx.
(According to FREQ.)
Variable reactance direct shift
Cece reer erresan
Frequency tolerance..................
(—20°C~ + 50°C)
Spurious radiation ...............6668
Maximum frequency
deviation (FM)...................6008
RPT. Tone burst frequency.........
Microphone ...... pei sabiae ian
[Receiver Section]
CHECOIUEY cs hiviuts wd conunateaiateuwnads
Intermediate frequency .............
Receiver sensitivity ................064
Receiver selectivity ................68
Spurious response ................0665
Squelch sensitivity .................06
Auto scan stop level..................
Audio OUtPUt.............c cece cece ee eeee
2m FM TRANSCEIVER ThR-7e8E8O
Less than +20 x 10~°
HI! Less than —60dB
LOW Less than — 53 dB
+5 kHz
1,750 Hz
Dynamic microphone with PTT switch,
5002
Double conversion superheterodyne
istIF 10.695 MHz
2ndIF 455 kHz
Better than 0.5 uV for 30 dB S/N
Better than 0.2 nV for 12 dB SINAD
More than 12 kHz (—6 dB)
Less than 24 kHz (— 60 dB)
Better than 60 dB
0.16 nV (threshold)
Less than 0.2 nV (threshold)
More than 2.0 watts across 8 ohm
load (10% dist.)
Note: Circuit and ratings are subject to change without notice
due to developments in technology.
© 1981-4 PRINTED IN JAPAN
B51-0936-00 (K)(M)(W)(T) 1000 @