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Tonight I did as you suggested and measured the B+ voltage at pin 4 of the LV regulator, which I presume is the same thing as the B+ regulator, aka THE regulator. You can see it in the attached image; it's an STR3115.
With the set plugged into my variac and isolation transformer I measured 135V at the regulator's output. It varied +/- 4V as I dipped the variac down to 110VAC and back up to 120VAC. I then plugged the set directly into line voltage and got 165V!
With power off, I checked the two electrolytic caps in the power supply using my Tenma LCR bridge. The 470 uF measured high at 576 but otherwise they were OK. I then measured continuity of the regulator and found 2 Ohms between pins 1 and 4. I'd expect it to be something closer to the 390 Ohm resistor that's across the same point.
I think the above proves the regulator is shorted and fubar'd. Before I order the NTE replacement, is there anything else I should check? I will check the flyback bypass capacitors tomorrow, I believe those are C437 and C443 in the second image, correct?
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