Solid State Guitar Amp Forum | DIY Guitar Amplifiers

I'm working on an amp that has me a bit stumped.  It is a Fender Champion 30 and it has hardly any volume passing through from the guitar to the speaker regardless of which channel it is on.  There is a good deal of hum/static as well.  The volume does work, but even zeroed out there is quite a bit of hum coming through the speaker. 

What's more weird is that when you shut the amp off, there is a split second where the amps sounds pretty loud and relatively clean - I'd dare say pretty much normal.  I've only looked at it for a few minutes and did some quick voltage checks and things appeared to be in order.

Any ideas?

Try to google its schematic or ask Fender for it.
It might have some malfunctioning mute circuit which stays engaged all the time, not just the first 30 seconds, and it gets off only when voltages fall after turn off.
But without a schematic I´m only guessing. :(

Quote from: J M Fahey on November 19, 2011, 08:23:29 PM
Try to google its schematic or ask Fender for it.
It might have some malfunctioning mute circuit which stays engaged all the time, not just the first 30 seconds, and it gets off only when voltages fall after turn off.
But without a schematic I´m only guessing. :(

Turns out I had a case of baby brain and was overlooking the obvious.  I woke up this morning and took another look, both input jacks had two bad solders each (out of four).  I resoldered those, then reflowed all soldered for the other jacks and potentiometers, works perfect now!

**edit**
Also, it wasn't working properly when shut off like I thought, it just makes a good thump when shut off and due to the input jack being messed up it sounded like it might have been working.