TrueTone D-717 filter cap polarity - Printable Version

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+--- Thread: TrueTone D-717 filter cap polarity (/showthread.php?tid=9212)

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TrueTone D-717 filter cap polarity - Eric - 04-03-2014

The schematic is not marked and someone has been in here before and I want to put things back so.
C11 neg goes to chassis pos to 80 heater
C10 Neg to center tap Pos to 80 heater?? or am I backwards?

http://www.nostalgiaair.org/PagesByModel/887/M0023887.pdf

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RE: TrueTone D-717 filter cap polarity - skyscraper - 04-03-2014

Both correct.

Interesting how the field coil is run on the negative side of the power supply, I haven't seen that before.

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RE: TrueTone D-717 filter cap polarity - Eric - 04-03-2014

Just wired it in they had one wrong, when I first brought the up voltage and when the set was at full voltage it had a loud 60cyc hum but that's all gone now. Thanks
Eric

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RE: TrueTone D-717 filter cap polarity - skyscraper - 04-03-2014

Sure. Did you replace the one that was wired wrong? Hundreds of volts the wrong way across a cap will likely shorten its life if it isn't already dead.

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