10-02-2022, 02:36 PM
>I believe that the pt is bad.
I'm not there yet.
Do you see a wire that come out of the pt and connects to the chassis? This should be the ct for the 6.3v heater winding. Unground it. It could be that you have a short that 1/2 of the heater winding is shorted to the chassis. Perhaps the dial lamp socket or one of the 6v tube sockets. This would give you the 2.9v or so at the lamp as you are seeing just 1/2 the heater voltage. Check for a low resistance to chassis gnd after you disconnect the gnd wire from the pt.
Using an ohm meter to detect these small amounts of resistance differences maybe difficult (a 1/2 to a 1/4 of an ohm). So use a small percentage of the ac volt applied to the primary may work just as good. Say 20% of 120 is 24vac to the primary should yield about 1.2v across the 6v winding.
I'm not there yet.
Do you see a wire that come out of the pt and connects to the chassis? This should be the ct for the 6.3v heater winding. Unground it. It could be that you have a short that 1/2 of the heater winding is shorted to the chassis. Perhaps the dial lamp socket or one of the 6v tube sockets. This would give you the 2.9v or so at the lamp as you are seeing just 1/2 the heater voltage. Check for a low resistance to chassis gnd after you disconnect the gnd wire from the pt.
Using an ohm meter to detect these small amounts of resistance differences maybe difficult (a 1/2 to a 1/4 of an ohm). So use a small percentage of the ac volt applied to the primary may work just as good. Say 20% of 120 is 24vac to the primary should yield about 1.2v across the 6v winding.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
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