Re: Power Supply Problems. HELP!

[u901841@student.canberra.edu.au (Hickey / Michael Gerard (ISE))]

In article <2ntep5$fpt@eis.calstate.edu> gachenb@eis.calstate.edu (Greg R. Achenbach) writes:
>OK, I need some advice.  I think I just blew out a power supply on my GS. 
>I was having some problems doing a reboot (Apple-Cntl-Reset).  The
>thermometer would fill up just like normal, but once it was full, the
>computer would freeze and nothing more would happen.  I tried it again and
>the same thing happened.  No problem (I thought), I'll just turn off the
>power and turn it back on.  NOTHING HAPPENED.  No power light, no nothing. 
>I reseated all the plugs and tried again, several times.  No dice.  Is my
>power supply history?  If not, what is going on?  If it is dead, where do
>I get a new one?  Is this a standard item that an electronics store would
>have, or do I need to go the Apple, Inc. route?  I saw another GS that had
>a fan mounted on the side of the PS.  Is this an advantage or a gimmick? 
>What would be a decent price to pay? 
>
>Thanks in advance.
>Greg Achenbach gachenb@eis.calstate.edu (soon to be ctp.org) Los Angeles
>County Outdoor Science School


Hi Greg,

I had a similar thing happen to me once but it turned out to be a damaged 
motherboard :-(

But first things first. You won't get a poer light for two reasons:

1.	The power supply is dead 
2.	You have a short-circuit across a 5 volt or 12 volt power rail 
	somewhere

The first is cheaper to fix.

First remove every card in the GS 
Then remove all external devices

power up (did it "light" up?)

If the lights came on, you have a problem with a card or a peripheral 
(esp disk drives). Add one thing at a time until you find the one which 
causes the fault to repeat.

If it _didn't_ you should listen very carefully to your power supply. If it 
is making a fast ticking sound then the switching power supply is 
protecting itself by turning itself off whenever a short is detected, 
then it is turning itself back on after a very brief delay, then turning 
itself off again.... and so on.

If it is doing this you have a short on the motherboard and you should 
try to talk someone out of a cheap GS or a new motherboard (try locating a 
ROM 3 if you can)

If it is NOT ticking it may be the power supply.

You can buy Exchange PS from Alltech for about $60 ph 619 721 7733 or call
Memory Plus Distributors on 602 820 8819 for a $75, 7 amp power supply
BTW get an internal fan for only $20... protects components from heat 
stress.

I have an upgraded ROM 00 motherboard with two types of power connectors.
One set is compatible with the Apple II+ power supply. I simply removed
the PS from my case and used one of my II+ power supplies for about 4
months (externally) until I could afford a 7 amp power supply.

It got REAL HOT but it did the job :-)  

Have fun...

Michael Hickey
u901841@student.canberra.edu.au