Super Champ XD

[Valvehead]

Have a weird issue with a Fender Super champ XD 15 watt combo.

This is intermittent -- rarely does it actually .

The amp gets "stuck" on the clean channel . Whats weird is NONE of the controls work, not even the volume. The amp is just stuck there on the clean channel wide open .

If i power it down it returns to normal for a while .


What could cause this ?

[Valvehead]

man i have bad luck.

pulled the board to look at solder joints . re did 5 or so .

installed board . Now I have nothing. amp powers up, no sound , no channel LED , the line out doesnt work either.


D17 shows 0 when i put the diode tester on it , both ways, im sure if i pull it out of the board it will test normal - thats my next move

the scem is very hard to read , but says D17 is a 1N52238 ? Of course i cant find that number

[Jazz P Bass]

D17

Can you please give a hint where D17 is.
What a crappy schematic scan!
Right from Fender!
Recheck that all the connectors are on the right way.
Connector #P5 has a slew of voltages labeled.
Check all of them.
Right it down on the schematic.
There are voltage test points all over the schematic.

[Valvehead]

ok..

well , i think i had a bad joint on one of the ribbon cables. There are 4 that go to the "pot" board. I re-flowed all of them and the amp came back to life.

D17 tested fine out of circuit.

So far the amp is working perfect. Im hoping one of the ribbon cable joints was the cause of the earlier problem ?

yea, that scem is HARD to read - you really have to zoom in the pdf page

[Jazz P Bass]

Got it

Glad to hear that you got it fixed.

[Enzo]

I don't see the schematic, but I'd bet my lunch money that the 1N52238 is really a 1N5223B instead. And that would be a zener diode, and not hard to find. Yes, I realize you no longer need one.

[Valvehead]

thanks.

the amp has been working normal for several days

[Jazz P Bass]

Super Champ

Way to go.
Here is the schematic for Enzo to laugh at.

[Enzo]

Ah. I found it on a disc I don;t use as often. Try this version

[Jazz P Bass]

Super Champ

Thanks Enzo.
That other one was bad.

[Valvehead]

thanks enzo