The short: How can I tell which flyback transformers would work for a 9" Macintosh?

The long: I've soldered on flyback transformers on old Macs that have gone bad in the past, but when my Mac Plus let out its magic smoke recently, I discovered that it's no longer cheap and easy to just get an old 157-0026-C flyback transformer from a dead Mac SE.

I can see that there are a lot of cheap flyback transformers available online, many of which specify things like "For nine inch black and white tube", are the right voltage and frequency, and have the right number of pins. But I have no idea what sort of things to even ask to find out if they are compatible.

Does anybody have experience with trying out non-standard flyback transformers? Failing that, any suggestions for where I can get an official one for cheap?

1 Answer 1


For starters, it would be helpful to know the wiring of the transformer. Haven't done it yet, though. But it should be not too hard do deduct pins for deflection coil (probably ground-symmetric), +12V and hot-end for the switching transistor and maybe a few more which I don't know yet.

If the coils in the new transformer have the same wiring, chances are that it will work pretty well, because frequency seems to match as you state. I would test it out. Worst thing that could happen is to blow up the switching transistor. IMO.

Would you mind providing a link to an example website (preferred with tech specs and wiring diagram) for these cheap transformers you mentioned?

I also have a bunch of POS VGA monitors with 9" tubes from different manufacturers - for use or for extraction of the tube, should I need one as a replacement for a broken one. Would be interesting if these are also compatible.

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