🚀 go-pugleaf

Question/poser for hardware hackers.

Our office Mega 4 has died. At switch on it flashes the keyboard light, and if
the volume is turned up throbs (bit softer than a click) loudly. Of course we
know the safety implicationsof fiddling with these things, so we immediately
opened it up and found the following...

The throbbing is synchonised to the PS fan wobbling to and fro. If we flick
start the fan the machine boots, but we get the "no keyboard" scream and no
response to keyboard or mouse. If we unplug the PSU from the motherboard it
starts fine (no need to flick the fan) and if we then plug it back into the
motherboard the system boots and all is hunky dory.

A bit of scope bashing reveals 'orrible spikes (about 25V worth) on the 12V
line which runs the fan when it is quivering, and nice smooth volts everywhere
else, anytime else.

Any ideas, guys? My guess is that that big electrolytic beside the PSU has
blown and is stuffing the 12V line, which in turn is stuffing the fan, but
replies from experienced bods are very welcome.

Jan Ameij
Oxford University Department of Applied Metaphysics,
ameij@uk.ac.oxford.vax

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Another message, primarily to Europeans...

Since, alas, it looks as if Info-Atari16 is Doomed, should we be thinking about
setting up a European Technical ST mailing list. It seems that most of the ST
interest and expertise is over here and it would be nice to go on sharing it.
Also, we might lose those whinging "Atari won't sell me a 100GFlop vector
processor for $200 - do you know how much IBM that would buy" etc comments that
waste all our time!

Long live the European Third World (insult copyright RC, 1990!)

Jan Ameij