Toroidal inductor rewinding. ATX PSU

[oliver602]

I have an old Rasurbo ATX PSU that failed.

I would like to try and rewind an inductor that got too hot. It is right next output wires, it has been removed in the photo.
Is this an inductor, transformer, choke, something else? Why is it so close to the output?

Could someone point me to the entrance of this rabbit hole?

[wraper]

If it was overheated, icon powder core IME very likely lost it's parameters as well. Rewinding will not make it a good inductor.

[wraper]

It's a group stabilization inductor. It helps several output voltages to follow each other, as there is no separate stabilization for each power rail.

[oliver602]

Can the iron powder core be replaced with one of the same size or are there other parameters that need to be matched?

[wraper]

You can only guess what the original specs were is you have no good core to measure. You could try making a test winding, measure inductance and calculate permeability to see if it makes sense for a good iron powder core. Core coating color indicates material type/permeability. Though there is no common standard AFAIK. But you could try to match it with color scheme here:

[oliver602]

The coating on this core is a dirty cracked brown so I'm not sure what to do here. Perhaps it was black. I'm not good at math. Outer diameter is 20.5mm, inner diameter is 12.25mm, width is 6.8mm.

It has three winding. I counted a turn when the wire passed through the centre of the core.
9 turns of 1.25mm diameter wire.
21 turns of 1.25mm diameter wire and
22  turns of 0.65mm diameter wire.

[oliver602]

How critical is the core size and permeability? Would it say be safer to go for a higher permeability core?

[T3sl4co1l]

It was most likely #26. #52 would also do.

Tim

[oliver602]

I rewound the inductor on a yellow/white core and the power supply is working again. I tested it with a 1.6A load on 12V and all the voltages look OK. But the inductor gets very hot after a few minutes.