philco 20 tube voltages...the radio works but is distorted

5/2/2004 5:11:11 PMsean

Hello, the radio plays with good volume, but after recapping everything except the power supply filter caps, it sounds distorted. 1st 24 pin2=248v pin3=74.5 gridcap=-10.86..
2nd 24 pin2=150 pin3=74 gridcap=-10.77
3rd 24 pin2=70 pin3=71 gridcap=-1.9
27 tube pin2=113 pin3=.47
71a pin2=85 pin3=-45
71a pin2=212 pin3=-46

5/3/2004 11:08:39 AMKen Owens

Measured to chassis, voltage on all 3 24A grid caps should be 0. Voltage on pin 2 of 1st 24A is right, but 2nd 24A should be the same. Pin 3 voltages on both are right. Voltage on pin 3 of 3rd 24A should be around 15. Voltage on pin 3 of 27 should be about -7. Voltage on pin 2 of both 71As should be equal around 250V. Pin 3 of both 71As should be around -60V.

:Hello, the radio plays with good volume, but after recapping everything except the power supply filter caps, it sounds distorted. 1st 24 pin2=248v pin3=74.5 gridcap=-10.86..
:2nd 24 pin2=150 pin3=74 gridcap=-10.77
:3rd 24 pin2=70 pin3=71 gridcap=-1.9
:27 tube pin2=113 pin3=.47
:71a pin2=85 pin3=-45
:71a pin2=212 pin3=-46

5/3/2004 8:52:31 PMsean

Hello, plate voltage on one of the 71a tubes is 150, other one is 250, so I have a bad output transformer, so I switched speakers and the plate voltage came up to other 71a tube. pin 3 of 71a tubes is 8volts....thats not right. You say pin 3 should be negative 60 volts? Even with the other model 20 speaker plugged into the chassis, it still sounds distorted.....unless that one is bad also, but at least I get 250 on both plates. if I have distorted output with volume, its gotta be in the audio section. oh yea that 8 or neg 8 volts is measured to chassis on pin 3 of the 71a tubes

:Measured to chassis, voltage on all 3 24A grid caps should be 0. Voltage on pin 2 of 1st 24A is right, but 2nd 24A should be the same. Pin 3 voltages on both are right. Voltage on pin 3 of 3rd 24A should be around 15. Voltage on pin 3 of 27 should be about -7. Voltage on pin 2 of both 71As should be equal around 250V. Pin 3 of both 71As should be around -60V.
:
::Hello, the radio plays with good volume, but after recapping everything except the power supply filter caps, it sounds distorted. 1st 24 pin2=248v pin3=74.5 gridcap=-10.86..
::2nd 24 pin2=150 pin3=74 gridcap=-10.77
::3rd 24 pin2=70 pin3=71 gridcap=-1.9
::27 tube pin2=113 pin3=.47
::71a pin2=85 pin3=-45
::71a pin2=212 pin3=-46

5/3/2004 11:14:47 PMKen Owens

The voltage on pin 3 of the 71As will vary with the quality of the tubes. -46 is a bit low, but not out of reason. The caps of the 24As definitely should not have any voltage on them. They go directly to chassis thru a low resistance RF coil.

:Hello, plate voltage on one of the 71a tubes is 150, other one is 250, so I have a bad output transformer, so I switched speakers and the plate voltage came up to other 71a tube. pin 3 of 71a tubes is 8volts....thats not right. You say pin 3 should be negative 60 volts? Even with the other model 20 speaker plugged into the chassis, it still sounds distorted.....unless that one is bad also, but at least I get 250 on both plates. if I have distorted output with volume, its gotta be in the audio section. oh yea that 8 or neg 8 volts is measured to chassis on pin 3 of the 71a tubes
:
:
::Measured to chassis, voltage on all 3 24A grid caps should be 0. Voltage on pin 2 of 1st 24A is right, but 2nd 24A should be the same. Pin 3 voltages on both are right. Voltage on pin 3 of 3rd 24A should be around 15. Voltage on pin 3 of 27 should be about -7. Voltage on pin 2 of both 71As should be equal around 250V. Pin 3 of both 71As should be around -60V.
::
:::Hello, the radio plays with good volume, but after recapping everything except the power supply filter caps, it sounds distorted. 1st 24 pin2=248v pin3=74.5 gridcap=-10.86..
:::2nd 24 pin2=150 pin3=74 gridcap=-10.77
:::3rd 24 pin2=70 pin3=71 gridcap=-1.9
:::27 tube pin2=113 pin3=.47
:::71a pin2=85 pin3=-45
:::71a pin2=212 pin3=-46