Output device question

[donegone]

Can I operate a solid state transistor amplifier (for testing purposes) without the output devices installed and without damaging any components? Thank you.

[Albert Kreuzer]

Yes.
Disconnect any load (speaker etc.).

[Steve Conner]

Yes, but it may not do anything meaningful. Some designs will output a signal, except with too little current to drive a speaker. Others will just stick to one of the rails, because removing the output devices breaks the feedback loop.

And within the designs that stick to the rail, there are some you can test-run by jumpering an output transistor base to an emitter, and others that would just explode if you tried that.

[donegone]

I just want to test the filter capacitors and the output devices are blown. Not testing for output signal. Thanks for the info.

[Wilder Amplification]

Wire up a light bulb in series with one leg of the mains as a current limiter, then use a Variac to bring the mains up slowly. If there are any shorted output devices, there will be enough current draw off the mains to light the bulb up brightly (the light bulb should hardly light up if at all on a fully functional amp). The light bulb will limit current to a safe level to keep anything from blowing up.

Now you may need an input signal to get the low current devices to draw enough current to exhibit any bad symptoms. As long as you do not have a load connected to the output, you can inject a signal, then scope the output rail to see if you have a clean signal present there.