Kenwood TS-140S/680S squelch mod anyone?

[SR385]

I seem to think I saw a mod so the squelch would work on all modes. Stock it only works for FM, but it would be nice to use it for AM etc., particularly just waiting for big signal activity on a channel.

Radio is a Kenwood TS-680S (same as 140 basically)

Anyone have a link or info?

 

[SR385]

I found it if anyone searching comes across this.

http://199.245.125.13/download/mods-t-z/ts680_2.txt

TS680s Squelch modificatios - adds squelch to all modes

Parts required

1 each 100 uF 20 v capacitor
1 each 10k ohm 5% 1/4W resistor
2 each 1N914 small signal diodes

Modification:

All modifications are to the signal board. Remove the signal board
to gain access to the bottom of the board.

Remove R178 100 ohm resistor. (I cut the land between C177 and R178)
(Removes FM chip control voltage) R178 is on the bottom of the
board.

Add jumper with a diode in series between IC6 pin 14 and the base of
Q57. Cathode of the diode goes to the base. (This is the squelch
trigger control voltage) Q57 is on the bottom of the board.

Connect a diode between the 8V line (very near IC6) and pin 4 of
IC6. This activates the FM chip (IC6) all of the time. Cathode goes
to pin 4, anode to the 8 volt line.

Connect a 10 k ohm resistor between IC6 pin 4 and IC6 pin 14.

Connect a 100 uF 25 volt capacitor between IC6 pin 14 and ground.
(This slows this quick squelch down a little bit)
Tests have shown (using commercial communications monitor) that
activating FM chip IC6 does not degrade IF strip performance at all.

 

[74IN]

You have a 140S?

Never mind,:blush:

 

[W5LZ]

I didn't have any problem using the squelch on the '140. Had to reduce the RF gain control for it to work, but it would work. (To the best of my knowledge my '140 hadn't been modified. Same for a '440 and '850.) ...?... - 'Doc

 

[station 716]

Good info. Mine works on FM only as well, as per the manual...kind of odd, but who knows.

 

[SR385]

Wow this got dug up eh?

I found an alternate fix for this, though it cost me $900.

Turns out an FT-1000MP has squelch in all modes ;-).

The 680S is waiting to be hooked up for psk31 and other digi use.

 

[W5LZ]

You know, that's the best 'fix' that I've heard of in a long time! -'Doc