Peavey VK 112 Weak Lead Channel

[DPM309]

I have a Peavey Valveking VK112 with very weak and distorted volume on the Lead Channel. The Clean channel works just fine. Tubes all tested good and even swapped out V2 with a good 12AX7 with no luck. Tube voltages also checked out. Ran a cord from the line out to another amp and am still having this issue with the lead channel so the problem must be in the preamp section, or the channel switching circuit. Also, I am getting no reverb. Any suggestions? I have attached a copy of the schematic.
Thanks, Dan

[TomCarlos]

Check my thread on the VK 112 - http://music-electronics-forum.com/t41321/

Take a look at V2 voltages and check the plate resistor.

[DPM309]

TC, both plate resistors for V2 (R101 - 150K and R102 - 100K) checked out. I am getting 155 VDC on Pin 1 and 259 VDC on Pin 6. I did check your thread out and that was one of the first things I looked at. Wondering if one of the channel switching relays is causing the problem. Any way to test these? Will also clean the footswitch jack since the problem seemed to start when the foot switch was used. Makes no difference with the foot switch disconnected.

Thanks,

[TomCarlos]

Ok...

Are you using the foot switch or is that unplugged?

Tom

[DPM309]

It is now unplugged. In fact I don't have it in my possession at this time. I am now using the channel selection switch on the front. Clean channel sounds great but when I push it in, I get a very weak, highly distorted sound even with the gain and volume turned all the way up.

[TomCarlos]

Ok... and the Foot switch jack J3... you have checked that, maybe use some cleaner like DeoxIT to make sure connections are ok? And the resistor next to it, R170?

[Enzo]

Test relays functionally. If signal is before it then it should be after it. Signal on the unselected branch should not pass through it. You can use an ohm meter to test continuity through it. The pins on the bottom may not be accessible, but they are always wired to something else, so we use things wired to the relay as test points: tube socket pins, resistor legs, etc

[Amp Kat]

Check all of the cable connections inside amp. Sounds like one may be dangling close enough for coupling but not seated all the way properly.

[DPM309]

Cleaned the foot switch jack and checked R170 which read 10 Ohms and chop-sticked all of the cable connections inside the amp with no luck. Still need to check the relays and will hook up my "listening amp" to see where exactly I lose the signal. Also noticed that the grey ribbon cable connecting Board 1 to Board 4 (P302 to P312) is just hot-glued to both boards. Looks like they removed the connectors and just soldered the cable wires directly to the board and used hot glue to hold in place. Will check the continuity of this cable and report back tomorrow on what I find.