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TS520
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1990-10-14
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4KB
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137 lines
SB-021
Service notes on TS-520 10-21-77
TRANSMITTER
1. No switching of final relay: Bad Q8 on X54-0001-00 2SA562Y.
2. No drive: C3 100pf in final box is cold soldered.
3. Low output: Check the plate load cap for touching plates.
4. 3.5 MHz low output: Replace burned 47pf 3KV at load wafer.
5. No TX: Final choke burned out in final VOX L8.
6. No RX or TX: Bad common amp. Q1 3SK35GR in IF unit X48-1060-00.
7. No ACC: No plate current Q2 3SK41 If unit X48-1060-00.
8. No TX relay: Q8 2SA562Y on VOX unit. Also R18 1K resistor relay
control.
9. No TX or RX: Check 9 volt terminal on FIX AVR (X43-1100-00) is loose.
10. No CW TX: Bad 9 volt regulator. Check D3 WZ061 on X43-1100-00.
11. No TX: Solder touch between TIF and key terminal on X44-1080-00.
12. No drive to TX: Check RL1 on GEN unit, small reed relay (X52-0010-
01).
13. No ALC meter action on 10 meters: This is normal for TS-520.
14. CW chirp: Q4 2SA606L on Fix channel AVR X43-1100-00.
15. ALC meter to maximum when TX: RFI terminal at X44-1080-00 is not
soldered.
16. No TX output: 82pf 3KV in final is burned.
17. No TX output: Q3 on RF unit 3SK41 X44-1080-00.
18. No bias: 10 ohm cathode resistors burned in final VOX.
19. No drive or TX output: R70-71 RF unit, R5 Rectifier unit.
20. No VOX: Q8 in VOX unit X54-0001-00.
21. No TX: 12BY7 is bad. Shorts and burns out. R71 and 70.
22. No carrier output: Q1 on Carrier X50-0009-01.
23. No drive - no screen voltage: R5 470 ohm open on rectifier X43-1090-
00.
24. No drive - no ALC: Q2 3SK35Y IF unit. Q3 3SK41L RF unit.
25. No RF output: C13 0.04uf at pin 1 of S2001A is bad.
26. Low mic gain: Q1 2SC1000 on Gen unit.
27. No TX: Misconnection of brown wire after installation of CW filter.
RECEIVER
1. Low Sensitivity: Touching RLT and 9V at function switch.
2. Receiver sensitivity: No -6v at AVR: Q8 2SC735 on X43-1100-00 is
bad.
3. Frequency Shift: Bad carreir Xtal 3395 on carrier unit.
4. VFO drift: C6 22pf, VFO unit.
5. No receive: Bad Q4, 3rd IF amp 3SK35GR on X48-1060-00.
6. Receiver sensitivity and bias current jump, -6v unstable: T1
oscillator transformer for -6v is bad on X43-1100-00.
7. Erratic AGC action: C11 100uf 16Von X431100-00. Fix channel AVR is
bad.
8. Frequency shift when warmed up: Q1 in VFO 3SK22GR.
9. No RX or TX: If unit C59 touch to T12 IF transformer.
10. Receiver noise: Q5 3SK35Y X44-1080-00.
11. Receiver sensitivity down: NBI terminal is pulled loose. Receiver at
IF board.
12. No S meter reading and RF gain CCW. No meter deflection: Q3 on IF
unit. Q5 on RF unit.
13. VFO frequency jumped: There is loose tension inside VFO.
14. VFO frequency shift: Cold solder of VFO output lead to VFO output
socket.
15. Blows fuse when first on: Check Q1 and Q2 DC-DC converter transistor.
One is possibly shorted.
16. Noise blanker inoperative: R6 4.7K resistor is broken at Q2 on X54-
1080-10.
17. Loud audio squeal: Q4 3SB473 on X49-0008-01 shorted.
18. Low receiver sensitivity: Diode D4 1S1587 on RF unit.
19. VFO intermittant: Wire to L1 in VFO is not soldered.
20. No receive: Q4 3SK35Y, Q5 3SK35GR on RF unit.
21. No receive: Q9 3SK35GR on IF unit.
22. Hash noise in receiver: Q3 on RF unit 3SK41.
23. Blows fuse: C31 power supply is shorted, 100uf 500v. Also check
associated diode D3, D4.
24. No RX on all bands: WWV switch is broken or a wire is loose or not
soldered.
25. Receiver sensitivity: Q5 on RF amp 3SK35Y.
26. Receiver sensitivity: NBO terminal on X48-1060-00 is loose.
27. Low audio: Check for purple wire touch to ground at 12 pin connector
in rear panel.
(c) 102177TKC