Amp turns on, then volume falls and sound gets distorted

[simarde]

Hi guys,

I've been given an old Traynor TS-50 amp, which semi-works. Here's the problem: Let's say I plug my guitar in the amp, while is it turned off. I then strum a chord, and turn the amp on. I can hear the chord for a fraction of a second at normal volume, then the volume falls and the sound gets distorted.

What can it be? A lot I guess, but if it works for a few second, the problem can't be that complex?

[Jazz P Bass]

The problem is not complex.
It works, then it doesn't.
Finding the solution to the problem may or may not be complex.
I would start by eyeballing the connections.
If any are suspect, resolder them.
Next, check all of the main voltages as marked on the circuit board.
You have to find what is failing.
Are the voltages holding up?
If it is a failure to pass a signal, you have to find where it is stopping.
The problem is most likely before that part of the circuit.
Isolating the problem to the preamp or the power amp is an efficient way of tackling the problem.