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AE5ME > TECH 28.03.16 15:44l 76 Lines 4592 Bytes #999 (0) @ WW
BID : 34441_AE5ME
Read: GUEST
Subj: //WL2K Re:TS-700A mods
Path: IW8PGT<IZ3LSV<IW0QNL<JH4XSY<JE7YGF<7M3TJZ<ZL2BAU<N0KFQ<AE5ME
Sent: 160328/0248Z 34441@AE5ME.#NEOK.OK.USA.NOAM BPQ1.4.64
If you are just looking to improve the performance of the radio, this comes straight from a Kenwood service bulletin:
Author: Trio-Kenwood Communication, inc.
Service bulletin no. 20 (18-10-1977)
Power supply
1. 9 volts down: The MFC4060 Q11 and 2SA495 Q9 are bad.
2. No 21V: Replace Q3 (2SC733Y (X43=1120-00) Power Supply Unit.
3. Dial light is VERY bright: Replace shorted Q2 2SA671 on rear panel.
4. Intermittant +9 volt supply: The legs of Q12 2SD235 are too short at the PC board. The leads were pulled away from the board. Replace Q12.
5. Power supply intermittant when tapped: Check for short leads on pass transistors, pulled out of circuit board.
6. No RX - No TX: Check diode D6 Zener in power supply. -6V supply. If shorted, replace.
7. No 13.8 volts at power supply: The wire on bridge D1 is not soldered.
8. +9 volts is okay, but 21 volt onl 16 volts: Q1 is bad in the power supply 2SC733Y.
TRANSMITTER
1. No modulation: Replace bad diode D15 Varactor on X52-1080-21.
2. USB or LSB is too high frequency: Recheck alignment of carrier board according to TKC service Manual procedures.
3. No RF out AM CW SSB: Replace D13 on GEN unit X52-108021.
4. FM RX and TX different frequency: Readjust all HET unit frequencies. Also check VFO linearity and adjust TX frequenc L3.
5. TX wrong frequency: Adjust L3 at X52-1080-21. 10.7 oscillator for final TX frequency.
6. No power out FM: Check for loose connection at L3, the 10.7 coil on GEN unit X52-1080-21.
7. No TX or RX: The fixed channel switch is in the wrong position.
8. Low poer out only 8W. 21 volt supply down to 16V: The protection diode D7 in the power supply is shorted.
9. VFO drift: Q1 3SK22Y in VFO is bad.
10. No TX FM: D15 on X52-1080-21 GEN is bad.
11. Drive control does not peak: This is normal - leave at center 500 position.
12. No TX: TX B terminal touch to ground at X52-1080-21 GEN unit.
13. No TX FM: Check diode D16 on GEN unit.
14. Only 3 watts out: Bad Q2 2N5642 in final amplifier.
15. The RF meter doesn't Work, but TX output okay: Bad diode D1 on BPF, the 1N60 is open.
16. No TX: Bad Q3 in mixer unit (X48-1130-21) 3SK35 (BL).
17. No VFO output: Cold solder joint of R2, 100 ohm resistor inside VFO on circuit board.
18. Intermittant TX: Bad ALC pot on mixer board VR2 (X48-1130-21)
19. No TX 147 Simplex: Loose resistor not soldered on rear circuit board of band switch.
Receiver
1. Spurrious signals on receive; if the output level or VFO is too high or mixer Q3 on HET unit: SN76514 is bad.
2. IF the noise blanker does not work: Check Q6 2SK19GR on X55-1120-00.
3. There is no audio from receiver-no 21 volts: Q1 2SC733(Y) in 21 volt supply is bad.
4. FM receiver sensitivity is down 30 - 40 db: Check 10.245 xtal at TP-1 on FM IF unit. If oscillator level is down, replace crystal.
5. Receiver sensitivity is intermittant and TX intermittant: Check contacts RT relay. Replace if bent or miss-contact.
6. If you cannot adjust the center meter: Maker sure Smeter start, VR4 is set at zero. If you cannot get enough adjustment with center meter, adjust VR1, replace Q4 (2SK19GR) on X55-1120-00.
7. No receive: Check for solder touch at 133 terminal on Het unit, if ther is no 133 het output.
8. No RX or TX and no VFO light: Check diode D2, 1N60 located on VFO circuit board.
9. VFO drifts or moves wit shock: Wire is not soldered VFO main coil L1.
10. No repeater operation: Check for wire that is touching at repeater switch.
11. No receive: Resistor R7 is touching Q1, 3SK41 on X55-1120-00 board.
12. No RX on 144, or any single band: Check HET xtals-realign the Het unit.
13. Center meter drifts for the 300000series and before: Send for the TKC bullent on Center Meter Drift.
14. VFO is intermittant when turned: There is loose tension on VFO rotor and Stator plate contact. Rebend tension spring.
15. RX audio output distorted: Chec Q4 on X49-1060-00.
16. No SSB or CW receive: Resistor R73 is touching to the can of T6 on X52-1080-21.
17. FM receive okay but SSB sensitivity is down: Check alignment of SSB IF transformers T4,5,6.
18. FM receive is bad: Bad T1 on the X48-1140-20.
19. Scratchy audio with internal speaker: Check for bad speaker.
20. No 146 band: Replace bad Het Xtal on Het Board.
----- Message from KD5NJR sent 2016/03/27 03:20 -----
Message ID: 0QU1SCNMKU71
Date: 2016/03/27 03:20
From: KD5NJR
To: tech@ww
Source: KD5NJR
Subject: TS-700A mods
R:160327/0325Z 34356@AE5ME.#NEOK.OK.USA.NOAM BPQ1.4.64
Does anyone have some simple tips for improving the performance of the old TS-700A all-mode rig ?
Thanks
Scott
kd5njr
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