Power transformer question - Printable Version

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Power transformer question - tpaairman - 01-04-2013

I'm working on an 84, and this thing is a mess. Whoever had it before tried to fix it up and did a horrible job. Anyway, The schematic shows that the transformer lines that go to the tube heaters has a center tap that connects to a resistor and cap by the 42 tube, as well as to another winding on the transformer. On the leads going to the heaters, I don't have a center tap wire.

It's part number 32-7180. Any ideas on this?

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RE: Power transformer question - Ron Ramirez - 01-04-2013

The center tap was eliminated on 2-1-1934, from then on one side of the filament line is grounded.

This change, and many others, are in the must-have Philco Changes in Models PDF that may be found here:
http://www.philcoradio.com/phorum/showthread.php?tid=215

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RE: Power transformer question - tpaairman - 01-04-2013

Thank you very much. Lot's of useful info there.

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RE: Power transformer question - codefox1 - 01-04-2013

Just an aside, it makes very little difference in most sets if the replacement transformer does not have a center tap for the 6.3 volt winding, just so long as one or the other returns to B- or ground. True mostly on larger amplifiers as well. There are several schemes use to fein a neutral ground to minimize hum including resistors and potentiometers wired from both poles of filament winding to "ground." Nine different ways of Sunday.

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