> > Thought: Is plug pack definitely DC and not AC? (Unlikely) .
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> Not higher voltage (measured using DC multimeter) - stable 4.5 VDC...
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> Spikes - can't say, have yet to use oscilloscope on the power rails...
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> I thought of the large capacitor, but have not done so.  Thanks.
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> The wall wart or plug pack is stamped or labeled with 4.5 VDC... and was =
ordered as
> such from DigiKey.  It is definitely DC because:

My suspicion would be that the unit relies on the internal battery impedanc=
e (as someone else suggested) to limit the power dissipation in whatever dr=
ivers are used for the LEDs. Because you have a nice low impedance supply t=
hese are overheating, producing the symptom you see.

I would try a resistor, somewhere between 1 and 5 ohms in series with one p=
ower pack lead, probably need to be a couple of watts capable, and see what=
 the display looks like.


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