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Uncle Bulgaria · 14th Mar 2019, 2:10 am

Aha! The smoke is back in.

Realising it still did it with the EL84 out, I traced it back to the coil and found there was a wiring error. Either from when I replaced the old resistor, or the reason it failed in the first place. Often it's the impetus to check with fresh eyes that's all that's needed!

It's sitting on now with no smoke.

Next issue: the hold-in solenoid (though it appears to be more of an electromagnet) is not holding in. It has the volts it should have on input and output (perhaps more, but this is with a DMM rather than an AVO8 as the manual requires). Also the run switch is sparking, even with a new capacitor across it.

14th Mar 2019, 2:10 am	#52
Uncle Bulgaria Nonode Join Date: May 2016 Location: Cornwall, UK. Posts: 2,333	Re: Ferrograph 4A: Restoration advice needed Aha! The smoke is back in. Realising it still did it with the EL84 out, I traced it back to the coil and found there was a wiring error. Either from when I replaced the old resistor, or the reason it failed in the first place. Often it's the impetus to check with fresh eyes that's all that's needed! It's sitting on now with no smoke. Next issue: the hold-in solenoid (though it appears to be more of an electromagnet) is not holding in. It has the volts it should have on input and output (perhaps more, but this is with a DMM rather than an AVO8 as the manual requires). Also the run switch is sparking, even with a new capacitor across it.