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Philco 40-135 Output Trans Replacement - Printable Version

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Philco 40-135 Output Trans Replacement - Eric - 03-09-2015

I have a Philco 40-135  print here
 http://www.nostalgiaair.org/PagesByModel/328/M0013328.pdf

It looks like I have a bad output transformer The Philco part # is 32-8063 can I use one from Electronics Antique  Supply P-T291 would this work? If not where can I get a suitable replacement?

Thanks 
Eric

RE: Philco 40-135 Output Trans Replacement - codefox1 - 03-09-2015

Tell the truth, just about any output transformer from a single ended tube set you can scrounge up will work. You can try to get one to match the likely 8 k load to voice coil (likely 8 ohms with the humbucker) by using a universal 3 watt replacement. Try to find the fault with the old one (nothing to lose by trying,) it might just be a corroded connection between t he winding and the lead(s.) Also be sure that nothing fried the transformer like a short or fault in the voltage divider network.

RE: Philco 40-135 Output Trans Replacement - Eric - 03-09-2015

The resistors  in the divider are good and the right value. I ordered one and a few other things to spread out the shipping I will tomorrow get the old one out and peel the insulation back. I saw in the tube chart that it was similar to a 6K6. 
Thanks
Eric

RE: Philco 40-135 Output Trans Replacement - Eric - 03-18-2015

Got my output xformer and notice that the new one has 490 ohms on the primary and the print shows 700 ohms should I add a 200 ohm resistor?

RE: Philco 40-135 Output Trans Replacement - Radioroslyn - 03-18-2015

Hi Eric
You are measuring the DC resistance of the pri wind What is kind of important is the impedance not the resistance. Just hook it up as is. No resistor needed. Definitely replace #46( .006 connected to the plate of the 7B5 or 41) I already forgot which tube it uses. if it is shorted it will take out the op trans. Also the cap in the tone control will do the same.
Terry

RE: Philco 40-135 Output Trans Replacement - Eric - 03-18-2015

(03-18-2015, 04:14 PM)Radioroslyn Wrote:  Hi Eric
You are measuring the DC resistance of the pri wind What is kind of important is the impedance not the resistance. Just hook it up as is. No resistor needed. Definitely replace #46( .006 connected to the plate of the 7B5 or 41) I already forgot which tube it uses. if it is shorted it will take out the op trans. Also the cap in the tone control will do the same.
Terry

I was talking about the resistance of the primary and I will not put a resistor in there. But you reference a #46 I don't see it. The tone is #32 and the caps off of 7B5 Output are 30,31 which I have replaced.

RE: Philco 40-135 Output Trans Replacement - Radioroslyn - 03-18-2015

Was using the riders link you posted pg 12-21. for the cap listing. The dc resistance can be very different and still have the same impedance. Has to do with the core size, wire size,
and the type iron or steel used in the core.
Terry

RE: Philco 40-135 Output Trans Replacement - Eric - 03-19-2015

(03-18-2015, 08:39 PM)Radioroslyn Wrote:  Was using the riders link you posted pg 12-21. for the cap listing. The dc resistance can be very different and still have the same impedance. Has to do with the core size, wire size,
and the type iron or steel used in the core.
Terry

I see were the mix up is, in the link it is the fourth page 11-51 that is for the 40-135, I get impedance just trying to find specs to help me trouble shoot with my limited  knowledge.
Thanks Terry