Re: IIgs repair help

[dempson@swell.actrix.gen.nz (David Empson)]

In article <1993Nov12.143419.10176@alw.nih.gov> Jim Owens <jow@helix.nih.gov> writes:
> 
> Right now there is a IIgs with a problem.  It is due to go into a
> Kindergarten classroom in January.  This poor machine will not recognize
> any floppy drive.  Instead, when it is turned on it immediately clicks
> while the light on the box flashes on and off rapidly and the light on
> the floppy drive flashes at maybe half the rate of that on the cpu box. 

The clicking noise from the power supply indicates a fault - something
is drawing too much power, such as a short between two of the power rails.

If you hear this noise, turn the computer off quickly!  Leaving it on
could damage the computer or the power supply.

The best way to track this problem down is to unplug all devices from
the computer (including cards in all the slots, any anything connected
to ports on the back panel).

Turn on the computer and see if the noise is still there.  If so, there
may be a fault on the motherboard or in the power supply, or a small
metal object shorting out a couple of pins somewhere, or something
like that.

If the power supply isn't making strange noises, turn the computer off
again, and plus in the keyboard, mouse and monitor, then try it again.

Keep adding peripherals back onto the computer until you find which
one (or which combinations) cause the problem.  Don't forget to turn
off the computer before connecting or disconnecting anything!

If connecting ANY disk drive causes a problem (and the same disk
drives don't cause problems on another computer) then the fault is
probably in the IIgs's disk connector, on the motherboard, or with the
+12V power rail (which is used by the disk drives).

Try swapping the power supply with another IIgs and see if the problem
follows the power supply.


Good luck - I hope you can track down the fault!

> A coworker's nephew had a similar thing happen to him and he claims to
> have fixed it by accessing using the Control Panel to reset something in
> the PRAM.  I was instructed to start the IIgs with the Option key down to
> get the Control Panel.  It didn't work, so now I am taking the manuals
> home to see if I can decipher what the nephew meant.  It occurred to me
> that if it is a parameter RAM problem, perhaps the battery is dead, but I
> don't know what happens if that is the case.  Any suggestions will be
> gratefully accepted.

This is a much more serious problem than parameter RAM corruption.
-- 
David Empson                                                               
dempson@swell.actrix.gen.nz                                                
Snail mail: P.O. Box 27-103, Wellington, New Zealand