H744 regulator whistle

From: ajp166 <ajp166_at_bellatlantic.net>
Date: Sun Jan 13 16:03:53 2002

From: Pete Turnbull <pete_at_dunnington.u-net.com>

>On Jan 12, 20:14, jpero_at_sympatico.ca wrote:
>> Sounds like PSU is reacting to overloading or medium shorts
>> downstream of that PSU outputs. Also can happen with dried
>> up capacitors (too high ESR).
>I don't think it's any of those. The regulators all make a similar
>when I put them on a dummy load drawing 5A, on the bench. And I'm sure
>it's not bad caps, as two of them are ones I repaired recently.

This is normal for them as well as the older H780. They are very loud
the pitch varies with load as well. That is a side effect of older low
low frequency switch mode PS designs of some 20+ years ago.

Received on Sun Jan 13 2002 - 16:03:53 GMT

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