FC5 freezes: due to bad Dell GX270 motherboard

[Paul Johnson]

We have had several 2 year old GX270 machines show random lockups.
The diagnostic lights on the back either show all dark or A-Green
B-Yellow C-Green D-Green.  I suspected it might be a Linux problem,
and asked in this list about it.  In the end, it is not a Linux
problem at all.

The symptoms include random lockups/freezes (with the video locked in
a snapshot of the screen) or sudden "power-offs" that leave the system
fan running but everything else dies.  The problem is correlated with
mouse usage, and seems sometimes to coincide with using the mouse to
stretch a window.  This symptom led me down the "what's wrong with
USB?" path, but it turns out to be all in the motherboard.  The
motherboard cannot supply power that peripherals need, so it appears
the mouse causes the trouble, but it does not.

Today I found out it is caused by a common defect in the motherboards
that Dell used in GX270.  The phone support person asked me if the
capacitor was swolen or leaking, and I did not understand what
swelling was supposed to look like.  But the technician came today and
showed me, and now I'll tell you. He said they were about to burst and
would have leaked very soon.

Where to check:  Look on the motherboard for small black cylinders
with silver tops.  The cylindrical capacitors are about 1/4 of an inch
in diameter and one half on an inch high.  The silver tops have an X
on edged them.  Those silver tops are supposed to be flat or slightly
sunken in, not convex (swolen).  They are NOT supposed to look like
cupcakes baking in the oven, in other words.

If you have a GX270 that displays any flaky behavior, I would ask Dell
to replace the motherboard.  As long as that is hanging over your
head, nothing else you fix will give much confidence.

-- 
Paul E. Johnson
Professor, Political Science
1541 Lilac Lane, Room 504
University of Kansas