HP82240a self test

[TomC]

This is very interesting in that the failure is intermittent.

While I'm not too knowledgeable on the 82240, I believe the processor relies on an interrupt from the IR receiver circuitry.

Perhaps this intermittent case is due to an 'edge' situation where the timing of the interrupt is late. If this is due to a timing condition, it could be due to an aging capacitor in the printer.

And in the first-mentioned case the capacitor has detiorated to the point such that the timing error is greater - causing the failure all of the time.

I wonder if anybody has (or can do)/done a study of the timing within the 82240; and further the timing within a failed unit.

Just some thoughts/several cents,
TomC
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(06-24-2022 01:44 AM)cesarb94 Wrote:  Mine does that too, but randomly. Sometimes it appears, sometimes it doesn't. However I did not notice any problems when printing from my 50g.