06-21-2018, 03:47 PM
I am trying to understand what’s going on with a model 89 code 121 power supply.
It’s the first model. #36 tube for the oscillator. The filter capacitors are numbered C44 & C46.
I only have the rectifier tube (80) in the circuit. The tube, transformer and speaker all check out ok.
The voltages across the transformer are all in spec. when the leads are removed from the circuit.
I substituted 2 (10mf) 450V electrolytic Capacitors for the filter caps, after disconnecting the original caps.
Powering up with just enough time to take measurements then shutting down, I do not see any rectification across the capacitor C44.
( full wave 60 cycle ac) I read 110VAC 50VDC.
C46 also does not show any rectification And reads 2VAC 53VDC any help or ideas would be appreciated.
Tom R
It’s the first model. #36 tube for the oscillator. The filter capacitors are numbered C44 & C46.
I only have the rectifier tube (80) in the circuit. The tube, transformer and speaker all check out ok.
The voltages across the transformer are all in spec. when the leads are removed from the circuit.
I substituted 2 (10mf) 450V electrolytic Capacitors for the filter caps, after disconnecting the original caps.
Powering up with just enough time to take measurements then shutting down, I do not see any rectification across the capacitor C44.
( full wave 60 cycle ac) I read 110VAC 50VDC.
C46 also does not show any rectification And reads 2VAC 53VDC any help or ideas would be appreciated.
Tom R
