[DM-MUG] Power supply for iMac G3

[Matt W]

See embedded response...

On Jan 25, 2005, at 8:48 PM, CW Smith wrote:

> Hey folks!
>
> I'm working on a Blueberry slot-loading iMac (350 MHz "5 flavors") that
> seems to be having some power issues.  It tries to boot up, sometimes
> chimes, sometimes gets as far as finding the system folder (OS9) 
> before it
> cuts all power and dies.  I've done some web research on the problem 
> and
> have narrowed it down to three possible scenarios:
>
> 1) The LED in the center of the power switch would sometimes become
> misaligned on these models, causing the switch to stick, in turn 
> causing
> problems at startup (similar to the ones I've described) and sudden,
> unexpected shutdowns and sleep.  I have opened up the iMac and 
> realigned the
> switch, and it seems to be operating properly, but still occasionally 
> hangs
> up.  Any suggestions?
>
You have to take the button out and shave it off (usually the bottom). 
You may have to shave off quite a bit and it is not easy as the button 
is very small and if you're not careful, you can slice off more than 
the button. It used to be a big problem. Funny how some people have 
lived for years with the Mac sleeping and shutting down at odd times.

This repair procedure used to be reimbursed by Apple for auth. service 
providers, but I'm fairly certain that it has been cancelled. You will 
know if the button is working because it doesn't get stuck and is free 
and springy. If so, then it should be fine.

> 2) I know that many models with the square PRAM battery (PowerPC 601's,
> 603's and 604's) would have boot problems if the battery failed.  This 
> one
> has the round PRAM battery, not the square one.  However, since it 
> only read
> 0.8 volt on my voltmeter (the label says 3.6 volts) I exchanged it for 
> a
> fresh one.  Although I seem to get a little further in the boot 
> process, I
> have not yet been able to fully boot this machine.
>
I believe the recommended replacement voltage is 3.4~3.2V.
>
>
Did you reset the logic board after adding the new battery? Take the 
battery out, wait 5-10 mins. and then press the grey button on the 
board. Replace battery and re-test.

Matthew