Is it normal for an A500 power supply to hum?

[motorollin]

Sounds like it is either (a) overloaded or (b) the plates in the transformer are starting to vibrate, which means the PSU is on its way out.

If you're just using it with an A500, then it's probably not (a), so you should replace the PSU.

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moto

[motorollin]

da9000 wrote:I forgot to mention that the humming happens when I turn it on, even when not connected to the A500. So definately not overloaded. The voltages register fine on my volt meter.

Ok so not overloaded then :-)

I wonder if it could be the "seating" of the transformer when I put everything back together. I'll open it up tomorrow and double check.

Possible I suppose. Check the positioning and seating of all the components just in case. If it's still doing it even when not connected to the A500 then there is definitely a fault with the transformer.

Could you explain why the plates on the transformer would vibrate? The transformer seemed fine when I opened it to do the soldering of the new fuse.

See Karlos' explanation above :-) The weaknesses in the structure of the transformer would probably not be visible to the naked eye, i.e. you wouldn't be able to move the plates around. As for how long it will last, well that depends on the extent of the damage, the load on the transformer, quality of build.......

It will die eventually, so I would just replace it now.

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moto