Philco 39-40 Voltage Readings Request - Printable Version
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+--- Thread: Philco 39-40 Voltage Readings Request (/showthread.php?tid=4293)
Philco 39-40 Voltage Readings Request - imacdaddy757 - 02-10-2012
Good morning, all. I just finished re-wiring a 39-30 Chassis Code 121 table set and will be firing it up today. I suspect the power transformer is bad, but would like to get
a set of voltage reading specs if anyone has them. They are not in the two service bulletins I have for this set. Anyone have something easy to use, short of having to pull the specs tube by tube from the site that has tube specs and base diagrams?
If it does test bad, anyone have a good transformer to sell? Looks like this one's been replaced by a close substitute many years ago already.
Regards,
Clarence
Re: Philco 39-40 Voltage Readings Request - codefox1 - 02-10-2012
Pull the 84 and measure the AC from pins 2 then 3 to the center tap of the HV winding. If they are very close, probably OK. With 84 removed do rest of tubes light up OK and transformer not getting hot? Maybe still OK, but filter capacitors at very least must be changed.
Re: Philco 39-40 Voltage Readings Request - imacdaddy757 - 02-14-2012
codefox1 Wrote:Pull the 84 and measure the AC from pins 2 then 3 to the center tap of the HV winding. If they are very close, probably OK. With 84 removed do rest of tubes light up OK and transformer not getting hot? Maybe still OK, but filter capacitors at very least must be changed.
Hi, Codefox. All the electrolytic and paper caps were replaced. All resistors tested and/or replaced. Replaced all the rubber-insulated wiring (it was really bad). Even replaced the dial lamp (using one from my Studebaker's instrument lamps, which use a nearly identical socket).
I did some basic voltage checks, and got no voltage (with 84 out) to the heaters.
Put the 84 in, and no voltage to the heaters or plates.
No tubes lit at all.
Since it measures 70 Megs resistance on the primary, pretty sure the power transformer is toast. I posted a Wanted ad for one on the Phorum. I hope I can get one, since this set has a nice cabinet and I've redone all the rest of the insides. It's a keeper for myself--I've put about 150 hours into it but had fun doing it and learned a few things along the way.
Regards,
Clarence