Fender power chorus channel switching

[g1]

That indicates that the problem is related to the switching contacts in jack #1. (red #4 & 5 in pic) (edit: or red #7 & 8)
Are they new real Fender jacks?
When amp is working through jack1 input, can you switch between channels and both work?

[pontiacpete]

Yes when in CH1 things work right. That is I can change channels from clean normal to channel 2. I wonder if the jack is just dirty.
I bought these from CE or studio sound. They might be a generic brand jack, not a fender jack.

[g1]

It won't be dirt/oxidization. The problem is when that switch closes (jack #1 pins 4 to 5) something is shorting the signal to ground. When you plug a dummy plug into jack #1 it breaks the connection between pins 4 & 5 so jack2 pin2 is no longer shorted to ground.
Try lifting the connection at jack1 pin5. Then apply signal to jack2 and see if it appears at jack2 pin2 or not (nothing plugged into jack1).

[pontiacpete]

I lifted pin 5 jack 1 and there’s no signal on jack 2. But there still is signal on jack 1

[g1]

I lifted pin 5 jack 1 and there’s no signal on jack 2.

That is with signal applied to jack2, correct?
And yet you get signal at jack1 with the signal applied into jack2?

[pontiacpete]

Yes that’s correct.
no, there is signal on jack 1 with the signal applied to jack 1. But no signal on jack 2 with signal applied to jack 2

[g1]

Then it seems like the ch.1 jack pin7 & 8 switch is the problem. Or C57 that connects to pin8.
One thing I noticed, ch.1 jack is called 'J2' on the schematic and ch.2 jack is called 'J1'. I had missed this, and all my references to jack1 meant ch.1 jack (red pins in pic). If I say jack1, I will mean ch.1 jack. I will not use the J1 or J2 designations. Sorry if this has caused any confusion.

Disconnect pin8 of ch.1 jack (red). If red pin5 is still disconnected leave it that way.
Apply signal to ch.2 jack and see if it shows up on ch.2 jack pin2 (yellow).

[pontiacpete]

I understood what you meant by jack 1 CH1. On the top of the PCB CH1 is J2 and CH2 Is J! . Weird on their part.
Anyway with pin 8 CH1 J2 disconnected there is signal on pin 2 of CH2 . What does it mean???

[g1]

Anyway with pin 8 CH1 J2 disconnected there is signal on pin 2 of CH2 . What does it mean???

Sounds like either C57 or the diode in parallel with it (C20?) is bad. Lift one leg of each of them and check if either of them measures short or low resistance.

[pontiacpete]

Both do not measure a short or low resistance out of circuit. Kinda looking normal with the ohm meter

[Enzo]

Um, 2-4-7 wired together in the right jack in the photo. 2-4-7 not supposed to be wired together.

7-5 wired together in left jack. 7-5 not supposed to be wired together in either jack.

Unless I am confused...

[g1]

Um, 2-4-7 wired together in the right jack in the photo. 2-4-7 not supposed to be wired together.

7-5 wired together in left jack. 7-5 not supposed to be wired together in either jack.

Unless I am confused...

That would leave ch.2 jack pin2 (yellow) disconnected from C1 (edit: not true, see post #28) . (C1 connects to yellow pin4 in pic). The schematic is so blurry it's really hard to tell what crossed lines are actually connected. I think 2,4,&7 yellow have to connect to get pin2 connecting to C1. I could be wrong.

[g1]

Enzo, I see that maybe you mean the trace from yellow 2 & 7 should wrap around but not touch pin4. Yellow pin4 would then only connect to red pin7 ?

[Enzo]

I think so. J1 pins 2 and 7 clearly connected together. The track from pin 4 crosses but does not connect to the 2-7 track. On the schematic. On the board art, I think you describe it right.

[pontiacpete]

That was it. I detached pin4 from 2 and 7 and connected the other pins that had been disconnected and it works perfectly. Thanks guys!! I really appreciate your help.

Pete