Most common problems can be found by careful visual observation. Look at all of the electrolytic caps to see if there is any bulging (most evident at the caps on the end of the capacitor) or leaking. You can tell if they are bulging by comparing them visually with others. Look to see if any resistors look like they have heat damage (looks dark or singed). Sometimes a resistor will vaporize and simply not be there--you will see only the leads of the resistor left on the board or in the circuit.
If you are lucky, and a bit handy, you can replace parts yourself. As someone mentioned above, discharge capacitors before sticking anything conductive (particularly your fingers) into the amp. Anything more and you are best off sending it to a technician. The good thing about tube gear is that almost anything is repairable.
If you are lucky, and a bit handy, you can replace parts yourself. As someone mentioned above, discharge capacitors before sticking anything conductive (particularly your fingers) into the amp. Anything more and you are best off sending it to a technician. The good thing about tube gear is that almost anything is repairable.