XT Power Supply help... (More Info)

From: Christian Fandt <cfandt_at_servtech.com>
Date: Fri May 1 09:11:32 1998

At 06:36 01-05-98 +0300, "Hotze" <photze_at_batelco.com.bh> wrote:
>OK... by some act of God, when I try to plug in the HDD alone, it spins up,
>along with the PSU. Now, when I take EVERYTHING out, that includes drives,
>cards, etc. and just give the motherboard power, it doesn't spin up at all.

Aha! Tim, I think I recall you mentioning that you had swapped the
motherboard. If you haven't done it already, check underneath the M'board
to see if one or more of the metal threaded standoffs is touching a trace
on the board. (I deleted previous messages in this thread so don't recall
if you did this already.) Actually, check if _any_ metal thing is
touching the board in places which it shouldn't.

If that trace is a supply line, then the PSU will shut itself down because
of a short circuit. If it is indeed shorting a supply line to earth then
find some sort of insulating material and affix it to that location(s) on
the board. Use a piece of very heavy paper or plastic sheet at least, say,
0.60" (1.50mm) or so thick.

I speak from personal experience on this one.

Also, look on top of the board and see if there's a metal chip, tiny screw
or whatever lodged between IC pin leads, resistor leads, connector leads,
etc. I have seen this before also, less likely possible in your case, but
give it a good visual in bright light anyway.

>Yes, the black pins are in the middle, I know I've got a good connection...
>could this be the "No power" line thingy? Should a real-XT case work with a
>clone-XT motherboard?

Usually, but as I've mentioned above with my experience, a few clone boards
lacked a mounting hole or two and underboard traces interfere with existing
mounting standoffs. Kinda dumb as the clone board manufacturer _should_
have stuck by the de facto mechanical standards but sometimes they made
"shortcuts".
Good luck
--Chris
-- --
Christian Fandt, Electronic/Electrical Historian
Jamestown, NY USA
Member of Antique Wireless Association
        URL: http://www.ggw.org/freenet/a/awa/
Received on Fri May 01 1998 - 09:11:32 BST

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