turbofeedus wrote: ↑Tue Oct 05, 2021 3:44 pm
I stuck the scope on the load resistor, as expected there's very minimal output. I couldn't grab a pic, it was about 1.5VAC P-P before clipping, and very jagged and ugly.
Also the bias voltage seems low for the idle dissipation? I was reading -37V, and that was about 22mA of current @ 430VDC on the plates, so less than 50% max diss. I would have to make the bias voltage even more positive to get 60-70% dissipation.
For example, the schematic shows -57V bias for 468VDC plates. Hard to imagine the bias voltage being doubled for an extra 10% plate voltage.
so if i understood, you dont have signal at the output?
you should read cca 50Vp-p.. if you dont have, this means you have a problem i output section/check for shorts -- output jack to the gnd/output transformer.
is the output tr. new? DIY?
Found it, thanks bepone and stevem.
I knew it was going to be something dumb.
For some reason I decided to use buss wire for the grounds on the output jacks, and the wire was laying across one of the little nubs for the tip.
Photo Oct 05, 2 01 16 PM.jpg
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