I have an Alpha 76 that I converted to 6 m years ago, which exhibited
the same symptoms. The problem was internal arcing in one of the
elderly electrolytic capacitors in the power supply. I ended up
swapping all the capacitors and the problem has never recovered. Even
if the sparking turns out to be coming from something else, it's
probably a good idea to change the capacitors anyway. While you're at
it, clean out all the accumulated dust on the tune capacitor plates.
73,
Jim w8zr
Sent from my iPhone
> On Nov 24, 2015, at 7:39 AM, Manfred Mornhinweg <manfred@ludens.cl> wrote:
>
> Ted,
>
> > My Alpha 76 periodically "snaps" loudly (arcs?) when idling...maybe
> > every 20-30 minutes. Any ideas what this may be?
>
> I don't know anything specific about that Alpha, but I have seen this kind of
> arcing at regular intervals when there is a simple power supply that has no
> bleeder and no load on it. There are very often lots of very narrow but tall
> spikes riding on the power line. When there is no load at all on a power
> supply, these will slowly charge the filter capacitor to such an overvoltage
> that something arcs.
>
> So I would suggest to check all bleeder resistors, first of all.
>
> Manfred
>
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