Am having a problem getting a good voltage reading on the 80 rectifier filamnet plates of my Philco's 84 (Riders 4-33,34). The reading that I am getting with my meter on each filamnet is around 65 volts way lower then the normal 340 DC (P to K) that I should be getting also to make matters worse the low voltage of 65 DC volts is of a negative polarity as displayed on my meter. I replaced with different rectifier tubes. I also tested the HV caps (8mfd and 4 mfd) and they also test the same with this low voltage and negative polarity. After changing both caps with new ones, I double checked to see that there polarity was correct which it was according to the schematic but the problem continues. I also checked the wire wound resistor (30) that affect B plus and it checked at 305 ohms which is not too far off.I would appreciate help in solving this problem. Thank you.

Not sure what "filament plates" are, but I think that you have a bad bias reference resistor.

In normal operation, there should be +300 VDC or more measured from either 80 tube filament pin to chassis ground. However...

A negative DC voltage will be observed if you measure from either plate to ground. The center tap of the B+ winding is referenced to chassis ground through the 325 ohm power resistor. With the diode action this creates a negative DC voltage on the center tap node (and both plates, as well). This negative voltage is used to create tube grid bias voltages; -65 volts seems a bit excessive- I'd expect only a dozen volts or so. You might check that the 325 ohm wirewound resistor isn't open. If it is, it would knock out normal B+ and may account for the "high" negative voltage (since your voltmeter impedance is serving as a high-resistance return path).

I re-read your original post and found that you had already measured the bias reference resistor, and it measured 305 ohms. That's not far enough off from 325 ohms to make a significant difference in operation.

So... my next guess is that the HT winding center tap wire from the transformer to this resistor has opened up. What is the DC voltage on the CT end of this resistor?

The problem:Not sure what "filament plates" are, but I think that you have a bad bias reference resistor.
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:In normal operation, there should be +300 VDC or more measured from either 80 tube filament pin to chassis ground. However...
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:A negative DC voltage will be observed if you measure from either plate to ground. The center tap of the B+ winding is referenced to chassis ground through the 325 ohm power resistor. With the diode action this creates a negative DC voltage on the center tap node (and both plates, as well). This negative voltage is used to create tube grid bias voltages; -65 volts seems a bit excessive- I'd expect only a dozen volts or so. You might check that the 325 ohm wirewound resistor isn't open. If it is, it would knock out normal B+ and may account for the "high" negative voltage (since your voltmeter impedance is serving as a high-resistance return path).
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The problem was like CV said it was a bad connection of the center tap HV wire from the transformer to condensor 30. I re-stripped and tinned the wire for a better conection and soldered it back to its post. That did the trick. Also got good good voltage reading on all the other tubes. Thanks for everyone's help and advice.

: Am having a problem getting a good voltage reading on the 80 rectifier filamnet plates of my Philco's 84 (Riders 4-33,34). The reading that I am getting with my meter on each filamnet is around 65 volts way lower then the normal 340 DC (P to K) that I should be getting also to make matters worse the low voltage of 65 DC volts is of a negative polarity as displayed on my meter. I replaced with different rectifier tubes. I also tested the HV caps (8mfd and 4 mfd) and they also test the same with this low voltage and negative polarity. After changing both caps with new ones, I double checked to see that there polarity was correct which it was according to the schematic but the problem continues. I also checked the wire wound resistor (30) that affect B plus and it checked at 305 ohms which is not too far off.I would appreciate help in solving this problem. Thank you.
:

:: Am having a problem getting a good voltage reading on the 80 rectifier filamnet plates of my Philco's 84 (Riders 4-33,34). The reading that I am getting with my meter on each filamnet is around 65 volts way lower then the normal 340 DC (P to K) that I should be getting also to make matters worse the low voltage of 65 DC volts is of a negative polarity as displayed on my meter. I replaced with different rectifier tubes. I also tested the HV caps (8mfd and 4 mfd) and they also test the same with this low voltage and negative polarity. After changing both caps with new ones, I double checked to see that there polarity was correct which it was according to the schematic but the problem continues. I also checked the wire wound resistor (30) that affect B plus and it checked at 305 ohms which is not too far off.I would appreciate help in solving this problem. Thank you.
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