Transformer substitution question

Garage door opener power supply transformer has an opened primary. It's actually a burnt coil wire right on the pin. I did manage to solder it back on but I'm worried it may fail again.

It's a 38V CT. Of course I can't find the *exact* replacement, but can I use a 36V CT ?

Thanks,

Reply to
giroup01
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Yes you should be OK ..

Reply to
kip

Or, have confidence in your repair. If it failed at the pin, it was a solder problem, not something more ominous.

If the new soldering was done properly, it should last. If it were something else, it's likely the failure would be inside.

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Reply to
Sam Goldwasser

You better be worried about a fire hazard ! There usually is a good reason for a transformer to burn it's coil.

There is nothing basically wrong with resoldering the part, but _please_ make sure that there is some thermal cutout device in the circuit. (And that it is thermically coupled to the transformer.)

--
Kind regards,
Gerard Bok
Reply to
Gerard Bok

Don't most/all transformer primaries have this?

Tom

Reply to
Tom MacIntyre

They should have. (But I wouldn't bet on it.)

Depending on where you live, extra care should be taken when you do the repair yourself. If there is a fire, an insurance company may require proof that you didn't tamper with any fireprotection that was present in the device.

--
Kind regards,
Gerard Bok
Reply to
Gerard Bok

Thanks for all the replies. What made me decide to replace the transformer was that I just didn't think the initial repair would hold, it was rather delicate to do. I had resoldered the tiny copper strand back on the solder tab, I think the strand still had some lacquer/glue/adhesive on it after attempting to clean it, and had less than a millimeter of play; I just wasn't satisfied I had enough contact surface and it was difficult to properly and cleanly wet the joint. Ugh.

I ended up installing the replacement transformer, a 36v CT 1A unit riveted outboard on the chassis, the original being 38v CT 500mA, and cleanly tiewrapped the cabling to an existing harness and onto the PCB.

I measured the same voltages on the various screw terminals as with the previous (flaky) transformer.

The fuse hasn't blown yet, and I have a fire extinguisher handy :-)

Thanks to all,

Reply to
giroup01

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