Weird Ampeg SVT3 Pro problem

[DesolateSphere]

Okay, so I bought an Ampeg svt 3 Pro about 6 months ago and it worked fine.
But now when I use it the volume level is waaay to low and it makes some weird rambling noise after some minutes of playing.
Now, this problem is temporarily solved when I put my gain on 25% and my Master all the way to 100% and play a few notes, it suddenly makes some kind of crack and it's fixed, but only for about 10 minutes.
Is there any hope? Or do I have to send it back?

[Jazz P Bass]

There is always Hope!
The question is what do you (can you) want to do about it.
The amplifier works.
That is a good thing.
It is not blown.
Now finding the problem, Ahh.
Troubleshooting skills & a decent array of test equipment will be needed.
(Or blind luck)
It could be something as simple as a bad solder joint.

[52 Bill]

If it's still covered by the factory guarantee, why not have it fixed by Ampeg? The only thing that I would suggest that you check would be to plug a spare guitar cord into the FX loop and see if that brings back the sound. If it does, then the return jack needs to be cleaned, which is something that nearly anybody can do, and will probably not void your guarantee.

[jrfrond]

I've repaired a bunch of those with cold solder joints.

[Mars Amp Repair]

you might also go for the simple ie:bad switch contacts in send/return jacks. Also to the bad solder connections point made, try smacking the amp on the top or just prodding the circuit board with a chopstick to see if indeed it is a bad connection issue as JRFront mentions...glen

[Ronsonic]

I've repaired a bunch of those with cold solder joints.

It says SLME on it doesn't it.

First thing to check for that kind of problem is the FX loop. Contacts get dirty and .....
(that was for the OP, John. You knew that)