Philco Model 66b - Printable Version

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+--- Thread: Philco Model 66b (/showthread.php?tid=2299)

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Philco Model 66b - bob913 - 03-26-2010

I want to replace the filter capacitors for the power supply. The schematic shows 2 each 8 Mf rated at 475 V. I believe they are wired in parallel. I am wondering if I can use 2 each 10 Mf rated at 450 V wired in parallel or if I can simply use 1 only 22 Mf rated at 450 V?

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Re: Philco Model 66b - bob913 - 03-26-2010

After making this post, I noticed there is a 3rd ground wire coming from the dual capacitor. I now believe the dual capacitor should replaced with 2 each 10 Mf capacitors. The 2 red wires to go different circuits.

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Re: Philco Model 66b - Steve Davis - 03-26-2010

Hello Resipla, You can use two 10uf capacitors @ 450 volts. The two parts of filter capacitor number 50 are not conected in parallel. The negative ends are both conected to can, which is conected to the center tap of the high voltage winding of the transformer. Note the cardboard insulators on the cans. The positive ends conect, one on each side of the speaker field coil. I think there may be some confusion because the conecting dot is missing on the schematic just below resistor number 28. Resistor 28 and the the output filter both conect to the top end of the field coil.
Steve

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Re: Philco Model 66b - bob913 - 03-27-2010

Steve,

Thanks for the clarification. The schematic also doesn't show which end of capacitors 50 are negative. I thought they connected to the center of the transformer but I was not sure.

Bob

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Re: Philco Model 66b - exray - 03-27-2010

Yes, the negative of caps 50 and 51 connect to the center tap of the transformer.

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