Solid State Guitar Amp Forum | DIY Guitar Amplifiers

I have some questions about testing electronics. Do I test a circuit with amp pluged in or unpluged on in put stages? Can I discharge a electrolytic in the pc board itself? How do I test a IC or operational amp? On a schematic (TP) does that stand for test point? Can I use a muti tester for these procedures? Thanks ahead of time for any input and lessons!

Please be careful.  Solid state amps run on lower voltages than tube amps but still can be dangerous, after all the mains voltages are inside it.

That having been said, most of these amps discharge themselves pretty quickly.  Always check with a meter until you understand how the circuit acts.

Yes we would discharge power supplies while still wired in.  REmoving a capacitor from the circuit board to discharge it would be a futile exercise.

If i want to check for shorted power transistors or the like I would work with the amp unplugged and discharged.  You can rarely take meaningful resistance measurements in a powered circuit.  (One exception might be measuring a JFET for on or off resistance)

In the other hand the ONLY way to take voltage readings is with the circuit powered up.

Most ICs are tested functionally, though if they start getting hot, that is often a sign of failure.

TP usually means test point, yes.  And Crate often has a chart of test point condition on their drawings.

Multitester?  Maybe.  Depends on what you are calling a multitester.  The tool of choice among technicians is usually  DMM - digital multi meter.  Though some (mainly old timers) still use VTVMs or the classic SImpson 260 type analog meter.

Thanks Enzo for the lesson, You were very helpful ! Three cheers to you!  ADV