fender deluxe 112 plus - Repair help

[0xdebe]

Hi all!
Here Debe writing from Italy!
I Have a Fender 112 Plus which was used in a music room in my town.
I think it's not worth repairing it in a service center, so I tried myself but I get stuck...
Here's what I've done:

• Changed C47 and C48 with similiar capacitors (same spec but smaller in size);
• Resoldered R67 and R68 because of burnt trace on pcb (they get very hot when power on);
• Resoldered CR26 and CR27 for the same reason;
• Resoldered jack in (each) and poweramp in;
• tested power rails on TP3-4 and TP5-6: TP3-4 was 42v instead of 39.6 as in attached schematics. Each rail stay constant while changing volume

Other tests (made without a load)

• applied a 1khz on input 1,2: preamp seems working (I can see a signal on preampout and also on the spk out).
• same signal applied to poweramp in. Here's come the first anomaly: I have to bend the stereo jack a bit to see signal on output (that's why I resoldered it unfortunately without success).

Now I orderer a 8ohm 50W resistor for dummy load. Meanwhile I tried with cone attached. When I attached it, signal disappear from output (I haven't tested yet preamp with load attached). Rails stay constant.

Thanks in advance
Bye
Debe

Attachment: Fender service manual I found on the net.

[Jon Snell]

Your voltage measurements are within specification. Probably a little high because the mains supply is not exactly 230volts.
I would replace the power amp in stereo socket and check the headphone socket.

[0xdebe]

Thankyou Jon for your answer!

A Little update.
I tried othe measurements with a 8ohm dummy load.
Preamp is working: I can see the input signal on R99, but after U1 nothing. If I measured correctly also on pin 3 of U1 there's no signal at all.

Is your suggestion still valid? Because I don't have spare jack socket right now. Maybe meanwhile I can check something else?

Thankyou for your patience :-D
Bye

[Jon Snell]

That's easy, an input jack is damaged and not unmuting the power amp.
C55 must have -16volts on it to allow Q7 to unmute the signal line.

[g1]

If you could get output using power amp in jack if you applied pressure to it, that jack must be bad. Like Jon said, some of it's contacts go to the mute circuit.

[0xdebe]

Hi all!
I'm back :-D

I Changed the four stereo sockets: high input, low input, power amp and headphones with no luck.
Now the situation is even worse: if I put a signal in low or high input, even if clean channel is selected (led green on), only distorted channel seems work. If I operate volume on distortion channel, I can see a signal on preamp out. Seems like distorted channel is always active. Channel selection TP20 works as expected (+15 clean / -15 distorted).

No signal at all on output. But if I touch with a stick in the area between R78 and R76 (the far right of the board) I can see a signal on the output (i attached a 8ohm dummy load). I reflowed everything in that area with no luck.

thankyou for your support!
Debe