Troubles with an old car radio.

[old_coot88]

Originally Posted by madmike17

Yes, the vibrator clearly runs. The only solution I can think of is to just turn the vibrator around. Could this be damaging if I'm wrong? What if i just disconnected the center tap to see if there is voltage when the vibrator is switched so that nothing could be harmed?

That's a good thought. But leave C34 in-circuit and disconnect everything 'downstream' from it. C34 can't be hurt by reverse polarity, even with full "B minus" voltage on it.

Also, voltage off the center tap should be DC, right?

Yes. And C34 should provide enough filtering for the meter (Digital meters tend to go nuts on unfiltered waveforms).

Is the truck negative or positive ground?