[rescue] Power and Imac

Wes Will wwill at siu.edu
Tue Apr 26 08:03:07 CDT 2005

At 08:45 AM 4/26/2005 -0400, you wrote:
>Arno Kletzander wrote:
>> ...an IMac DV (slot-in drive) which seems to have a bad PSU
>> as well. It just sits there and emits a barely audible
>> high-pitched noise, but won't turn on.
>   That sounds like what I've been told is a bad flyback transformer,
>though I'm no expert. COuld it also be the miserable Analog Video Board,
>which regularly dies in these CRT iMacs?

Yes it could very well be, but the whine is usually indicative of a
high-voltage leak somewhere.  Open it up completely, turn it on, stand back
a bit and don't be tempted to reach in when you can't see, and flip off the
lights.  Look in, see if you see any arcing or bluish glow on the high
voltage board.  There are occassions when it's just an abraded wire
carrying a lot of charge, and it leaks.  Sort of like spark worn-out plug
wires on a foggy night....

Not likely, but I have done televisions (and spark plugs) that way.  Turn
the lights on and the power off before you reach in.  We did this to death
a few months back, the snap wouldn't likely hurt you by itself, but you
might fall or smack something sharp when you flexed backward if the HV cap
got you with anode voltage.  (We are our own worst enemy, to misquote Mr.
Pogo Possum.)

wes will

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