Philco 76 output transformer #2848 - Printable Version
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+--- Thread: Philco 76 output transformer #2848 (/showthread.php?tid=21906)
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RE: Philco 76 output transformer #2848 - Arran - 01-13-2021
That's sort of an odd design for an output transformer, most of the ones I have seen have the secondary on the outside, not the primary.
Regards
Arran
RE: Philco 76 output transformer #2848 - Stan the Man - 01-13-2021
I tried my best to exact a copy of the original. I dont know that I want to do another. And I have yet to see it in action, so..
Stan
RE: Philco 76 output transformer #2848 - Stan the Man - 01-21-2021
Well I finally got my output transformer stitched up, and back on the speaker. To my surprise it works. I have yet to do the voltage checks, and I'm not real happy with some of the things I had to do in the end. This was my first, maybe the next will come out better. The big thing is, I did it, and it worked!
RE: Philco 76 output transformer #2848 - Stan the Man - 02-02-2021
Well, The radio seems to play ok, but voltage checks have me scratching my head. The voltages all seem to be a bit high(DMM), but I have more than double the listed plate voltage on the Detector tube, and the first AF tube. By the resistance chart things are almost spot on, and PT voltages are good. Tubes good. My new field coil, by the DC resistance is 3245ohm. My rewound OPT is the only thing I can think of that may not be exactly like it should be.
RE: Philco 76 output transformer #2848 - Radioroslyn - 02-02-2021
The plot thickens how about the voltage on the 24A's plates? There are fed off of the same line.
RE: Philco 76 output transformer #2848 - Stan the Man - 02-02-2021
Keep in mind, these were taken with a DMM.
Stan
RE: Philco 76 output transformer #2848 - Radioroslyn - 02-03-2021
Would check #14 100k resistor. If drifted lower in value this will raise the voltage. Poor ground at #14. Weak 24A. Clean heater contacts on socket & tube (24A det). Just for grins you can try grounding the control grid (grid cap) and check the plate voltage. If the voltage drops to a more normal level you may have a open 2ndry on the rf coil or bad ground.
RE: Philco 76 output transformer #2848 - Stan the Man - 02-03-2021
Thank you for that Terry. You have given me some things to look at. I am now unstumped, for now.
Stan