Fixing a Fender Champion 30 Amp

[nicksaysword]

Alright, so after testing out a bass guitar [an Ibanez] on this amp [Fender Champion 30] to make sure the bass guitar worked properly, the amp appeared to not be putting out sound. I'm hoping I wasn't just being an idiot by plugging the bass guitar in, but if I was then tell me, hopefully it was just coincidence. I cranked the amp to full volume and was only able to get a weak sound. The volume on the bass was up, it wasn't that. Tried a second guitar [a Dean MLX series] which I had been previously using with this amp and it was the same deal, drive volume did not seem to be able to put out any sound whatsoever. As I am not versed in amp repair, I tried replacing the fuse, which as I expected, did nothing. I looked into the issue a bit and it seemed that I would need to solder a part of the amp's circuitry after finding the bad connection with an oscilloscope or another similar tool. I would rather not get too far into this without more opinions on the matter in case [crossed fingers] it's a simple fix that I just can't seem to find. I cleaned the amp out with contact cleaner, got the bits of dust out of the body of it, basically I did all the noob troubleshooting stuff. Would massively appreciate some input on this, thanks.

[Rob's Radio-Active]

If you unplug the cable from the guitar, and touch the end of the plug at the guitar end with your finger, does the amp make a buzz like normal?
If the controls are set properly, it could be a lot of things...bad speaker...bad tube...etc. Try plugging in a different speaker of similar power capability and ohms.

[DrGonz78]

The one aspect of the amp that jumps out at me is the External Speaker jack. When you connect an external speaker to that jack output it will cut off the internal speaker. That jack may be dirty or even damaged(worn out) thus impeding the signal with a bad contact on the tip part. You could try connecting an external speaker cab to see if that makes the amp come to life again. If you have an ohms meter you can measure resistance right at the jack on the tip contacts to see if it making good continuity. There might even be other issues with the amp that include bad solder joints, loose connections or dirty pots. To check for loose connections ball up your fist and give the amp a whack right on top. Play some guitar or an mp3 into the input while doing that to see if it reacts to the thumping on the amp. No tubes in this amp so don't worry about that one...