02-26-2021, 10:41 AM
You know, one of these days I won't have such a problem tracing down voltage problems. But I've found that the older you get (at least me) the shorter the retention span. This is the third voltage problem in the last few months that I haven't been able to solve.
Anyway, re-capped the unit. replaced all the dogbones as they all drifted 25% or more higher. Checked the choke and the field coil, and all the RF coils. Traced the schematic 4 times and found no errors, cold solder joints, broken wires, etc. Modified the input transformer. Re-checked all the tubes. Can't find a problem anywhere.
And these are the voltage readings I get (in red). Measured with both a VTVM and a digital meter (which was slightly higher than the VTVM). Power transformer voltages are very close.
[Image: https://i.imgur.com/XILAnCv.jpg]
[Image: https://i.imgur.com/t9vqzqy.jpg]
Anyway, re-capped the unit. replaced all the dogbones as they all drifted 25% or more higher. Checked the choke and the field coil, and all the RF coils. Traced the schematic 4 times and found no errors, cold solder joints, broken wires, etc. Modified the input transformer. Re-checked all the tubes. Can't find a problem anywhere.
And these are the voltage readings I get (in red). Measured with both a VTVM and a digital meter (which was slightly higher than the VTVM). Power transformer voltages are very close.
[Image: https://i.imgur.com/XILAnCv.jpg]
[Image: https://i.imgur.com/t9vqzqy.jpg]
