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I've swapped Q802 and replaced fusistor R417 with a 500mA fuse. Since the meltdown mentioned above I haven't been able to get anything out of the flyback, no HV, no filament voltage, and no LV. While measuring voltages on the bottom of the board I heard a sound like glass breaking and quickly powered everything down.
I thought maybe the regulator had overheated and the sound was the little mica insulating sheet cracking but it turned out to be the sound of R808, the big 210Ω/20W power resistor, overheating and splitting in half lengthwise. It was so hot I had to wait about 10 minutes before I could remove it. Strangely enough, it still registered close to it's stated value. I don't have any resistors that big laying around so I'll have to wait until I order some parts to replace it.
Bypassing the regulator and R808, I tried lowering the input voltage to about 90V with a variac to get exactly 125V DC going into the flyback's primary through fusistor R417, with the result being to instantly blow that fuse. Would I be correct to assume that I've damaged the flyback while diagnosing the power supply issues?
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