Building upon the designs of the TS-120, TS-130 and TS-430, the TS-660 Quad Bander adds coverage of 6 Meters at the expense
of 80 - 17 meters. There are a frightening number of adjustments but fortunately the TS-660 holds it's adjustments
well so very little maintenance is required. One concern is that all of the PC boards, including the Final, are
of brown paper phenolic construction (NOTE: needs verification).
Preventive Maintenance
- Replace C119 and C120 (1000 �F @ 16V) on IF board.
- Check to see if any mods and Service Bulletins have been applied.
- Carefully apply contact cleaner/lubricant to all switches and pots.
Repair
- See troubleshooting chart in Instruction Manual and Service Manual.
- On the RF board, L4 and L38 have their metal shields grounded with a leaf spring. The springs tend to push L4 and L38
sideways breaking the soldered connections. Remove the existing solder, reposition and resolder. Remember to replace
the springs.
Adjustments and Alignment
- See ADJUSTMENTS in Service Manual
- Carrier point adjustments can be made easier by using Spectrogram or another FFT display.
- S-Meter can be adjusted to match standards (S9 == 50�v and 6db/S unit) from about S3 through 40 over S9.
| uv | 0.2 | 0.4 |
0.8 | 1.6 | 3.3 | 6.3 | 12.6 | 25.1 | 50 |
160 | 500 | 1600 | 5000 | 15000 | 50000 |
|---|
| S |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 over |
20 over |
30 over |
40 over |
50 over |
60 over |
|---|
Mods and Improvements
- Apply SB-856.
- Muffled received audio - The TS-660 has a roll-off at about 2800 Hz.
- SSB - Change high frequency rolloff for better clarity. Change C40 on the IF board to 0.003μF or 0.0047μF.
- FM - On FM-660
change C50, 0.033μF to 0.0033μF or 0.0047μF. Restores high frequencies on received FM signals.
- Muffled/mushy transmitted audio - On the Switch Unit, change C6, 0.015μF to 0.001μF.
- Selectable fast/slow agc - Remove D53 on the IF unit. Attach where cathode of D53 was through new diode
to a switchable source of 9V.
9V on = slow agc, off = fast.
- LSB ? - LSB can be added using circuits similar to those in the TS-120, TS-130 and TS-430.
An 8.8285 MHz crystal would be required.
- Adjustable sidetone pitch - The sidetone circuit is similar to
what Kenwood used in other rigs. R129 on the IF board may be adjusted if needed.
