Again, if the hi=lo switch is missing, use a meter to determine which primary post is for the higher mains voltage. you should have 3 lugs for the power transformer primary. Probably can't tell with resistance measurement of the primary.
photo MG_1056.jpeg of my AW-15 transformer primary lugs for reference. Notice the partly obscured 110 and 120 labeling.
So REMOVE the rectifier tube. Then move the power cord connection between the two primary lugs and see which give you the LOWER voltage measured between the high voltage center tap and one of the tube socket rectifier plates. use the 500 volt AC scale. Maybe put one hand in your pocket for safety when you power on. You are seeking the one that shows a LOWER high voltage.
While you are at it, double the measured voltage to see about what your first filter cap is seeing as a full wave output. CAUTION: With the rectifier tube inserted, the speaker and receiver absolutely need to be plugged into the amp to draw down the working high voltage somewhat.
If you are inadvertently feeding 125 volts AC into the "lo' side, the B+ voltage will be way high.
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Again, if the hi=lo switch is missing, use a meter to determine which primary post is for the higher mains voltage. you should have 3 lugs for the power transformer primary. Probably can't tell with resistance measurement of the primary.
photo MG_1056.jpeg of my AW-15 transformer primary lugs for reference. Notice the partly obscured 110 and 120 labeling.
So REMOVE the rectifier tube. Then move the power cord connection between the two primary lugs and see which give you the LOWER voltage measured between the high voltage center tap and one of the tube socket rectifier plates. use the 500 volt AC scale. Maybe put one hand in your pocket for safety when you power on. You are seeking the one that shows a LOWER high voltage.
While you are at it, double the measured voltage to see about what your first filter cap is seeing as a full wave output. CAUTION: With the rectifier tube inserted, the speaker and receiver absolutely need to be plugged into the amp to draw down the working high voltage somewhat.
If you are inadvertently feeding 125 volts AC into the "lo' side, the B+ voltage will be way high.
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