My solid-state amp isn't putting out any sounds lately. But when I turn it off there is a short time where I can hear my guitar playing until the amp turns completely off. What can cause this strange behavior?
In order to diagnose the problem with this amp you'll need to trace a signal through the circuitry of the amplifier to find the defective component. If I had it on my workbench, the first thing I would look for would be defective field effect transistors (FET), I've seen a few amps act this way and replacing the FETs fixed the problem. If the problem isn't with the FETs, then I'd check for a defective zener diode, this can also cause an amp to act in this manner. Both parts are inexpensive and easy to replace, so it shouldn't break the bank to fix it.