40-190 Output Transformer - Printable Version

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+--- Thread: 40-190 Output Transformer (/showthread.php?tid=1471)

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40-190 Output Transformer - Bob - 11-05-2008

Hello
I just got a used transformer, Philco # 32-8053. It reads 309 ohms black to white, 143 ohms from ct to black, and 166 ohms from ct to white. The schematic has 210 ohms ct to black, and 240 ohms from ct to white. I noticed that the bad transformer has an M after the part number. The used one I got has an N after the part number. Will this one work or is there a way to make it work? The parts list dose not have a letter after the number.
Thanks for any help
Bob

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Re: 40-190 Output Transformer - planigan - 11-05-2008

Bob, I would not be too concerned with the resistance readings of the replacement transformer. More important
is the voltages. Are the voltages correct? If so it should be OK. PL

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Re: 40-190 Output Transformer - codefox1 - 11-08-2008

Just a couple of more things to check before you fire this one up again, check the two output tubes (type 41) for shorts or evidence of arcing at the tube sockets, and then bring the set up slowly with a variac and monitor the B+. If there is a short in either of the output tubes, or arcing at the tube socket, your replacement output transformer will be in peril. Just for fun, you can carefully open up the old output transformer, and see if the "open" is just a lost connection, or a burn out caused by excessive current. I have seen quite a few cases where the connection of the fine primary windings to the cloth covered leads corrodes, or arcs to the transformer casing, and sometimes this can be fixed. Since this is a push pull transformer the primary is center tapped and you may have continuity in only half the winding. If you do have some contiuity and no shorts to the metal casing, save the transformer. You may need it someday to replace a burned out choke.

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Re: 40-190 Output Transformer - Bob - 11-08-2008

Want to thank you both for the info. I am still stripping the radio down ( hope I can get it wired back up again ). I am a retired machine tool electrician so this is all new for me, but it is fun. Am learning a lot from this Phorum and other web sites. I didn't see any signs of a short and the 41 tubes check alright. I think I will do as codefox1 suggested an take the old transformer apart. I'll let you know what I find if anything.
Thanks to both of you
Bob

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