ATX Power Supply: I think they forgot something?

[TerraHertz]

Oh good, Methyl Ethyl Ketone, the most scary of all common solvents. Definitely something to try outside.

[ptricks]

Unless it is a really expensive transformer core you are better to just buy cores than try to re-wind old ones.  A lot of the transformers now use laminated cores and they really suck to have to put back together.

[TerraHertz]

pticks, are you talking about ferrite cores for switchmode supplies? I don't know what you mean by 'laminated' in that context. While iron core transformers have always been laminated, as without the laminations power loss due to eddy currents in the core is untenable.

I'd like to be able to salvage ferrite cores and formers, since I have mounds of old switchmode supply PCBs, and now and them a need to do a custom supply. Buying a suitable ferrite core in unit quantities ranges from difficult to impossible. At least with switchmode supplies you can be sure the ferrite used is roughly suitable to the application.

[ales22]

You can heat up the whole transformer with hot air gun or better in well regulated owen to around 150C (maybe 200 or more) until the epoxy becomes slightly soft. Raise the transformer's temp slowly and evenly or the ferrite will crack. Then use some pliers to carefully detach ferrite cores and coil. It takes time, require some skill and is not successful everytime.

[SeanB]

The toast until well done method doeas always work, though the former will be unusable afterwards, and you will have to clean off the char.

[ptricks]

pticks, are you talking about ferrite cores for switchmode supplies? I don't know what you mean by 'laminated' in that context. While iron core transformers have always been laminated, as without the laminations power loss due to eddy currents in the core is untenable.

Never say always , There are transformers that consist of blocks of solid iron where the 'I' end piece can be removed with a hammer and a few hits, the bobbins slide off easily, mainly in really old gear . Then there are the cores that replace solid iron with plates of iron or steel bolted together. Next they went to laminated cores same as the solid cores but now glue or varnish replaces the bolts because the bolts had to be kept out of contact with the core.   And finally there is the alternating EI core. The alternating EI core are the ones I hate to work with. They alternate E and I plates and can take quite a long time to put together. Having to completely disassemble a transformer to try out a new winding is a major pain, when with the older cores you could easily change out a bobbin in minutes.