Verify a(maybe) dying diode caused by a bad capacitor???

Diodes are cheap. It was stressed. Replace it.

Mostly they either work or don't. Short or open. Spend a buck and replace it.

It seems like the repair worked, but the hot diode concerns me. Your description is a little hard to understand. Did the diode get hot before or after the capacitor was replaced?

In any case, the black mark by the diode isn't a good sign. Whether the mark was cause by the diode overheating or leakage from the bulging capacitor, I would replace it. As another poster tersely pointed out, diodes are inexpensive.

For a definitive measurement, don't test the diode in place. Rather, unsolder one of its leads from the circuit board and then test it with your voltmeter's continuity checker.

-Dave

If it tests good in-place, it won't test bad when removed. :)

However, the inverse (??) may be true.

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I see lots of bulging caps in the power supplies of cheapo DVD players - I probably repair 2 or 3 a week on average. I have found it very rare indeed for the feeding diode to actually be faulty. Usually, it's just a case of replace the cap, and that's it. It is not at all uncommon for the diodes in these supplies to run very hot, and discolour the board. Sometimes, if there is room, I bend a small piece of metal around the body of the diode, with a bit of heatsink paste in there as well, to help cool it down a bit. Bear in mind if you do replace it that it will be a Schottky type ( I'm assuming that this is a switch mode PSU ??? )

Arfa

Is the power supply being overloaded? If it's not and the output voltage is correct, I wouldn't worry about a warm diode.

Bad advice.

Some components may have been stressed by the fault The charring near the diode indicates this.

There's NO WAY to prove the diode hasn't had its reliability compromised through overheating so it should be replaced as a precaution.

Graham

Or a fast-recovery type.

Using a standard diode will guarantee long term failure although it might work for a bit.

Graham

through

The charring proves that the diode has always run hot and it is likely the way it is meant to be. A board is not charred in just a few hours of operation.

Messing and replacing these diodes is a good way to risk the power supply, and given that it runs hot I would be very careful with the type I replace it with, get it wrong and you may blow the supply again.

Unless the in-circuit test is turning on a junction of another semiconductor that's in the same circuit, and the diode is open.