repair of motherboard

[Kevin O'Gorman]

In article <784 at cbnews.ATT.COM> mark at cbnews.ATT.COM (Mark Horton) writes:
>Help!
>
>I have a UNIX PC 3B1 (stargate) which just lost some kind of disk
>function on the motherboard.  AT&T wants close to $2000 to replace
>the motherboard, which is outrageous.
>
>The problem only occurs on boot.  It tries to boot, and it just sits
>there pretting little squares on the screen.  The floppy disk light
>stays on, and the LEDs on the side all 4 stay on.  This happens
>whether there's a floppy in the disk drive or not, so I can't boot
>diagnostics.  AT&T's hotline says it sounds like both WD1010 disk
>controller chips have gone bad, but I find it hard to believe this
>given the other information I have.
>
>The problem was once intermittant - 9 times out of 10 it would do this,
>but sometimes it would boot OK, and once it booted it was fine, both
>for hard disk use and for the floppy.  Now I've tried it about 15
>times and it has failed every time.  I still keep trying once or twice
>just in case it might come up.  Last time I left it up for 20 days
>before I had to move it, and it ran flawlessly once it was up.
>

Hmmm.  I could have saved myself the cost of service recently, only
$120.00 because I don't use AT&T, but I should share what I learned
anyway.

The system would not boot at all.  It did not even get as far as
clearing the screen.  The leds were not cycling.  The machine had a
history of freezing during operation in about this way, which had
been intermittent and  increasing.  I had thought it was a problem
related to software, particularly uucp, but was not sure.  The problem
stopped being intermittent just after I had the case apart (something
that happens fairly often here).

The service tech was not familiar with this box, but they undertake
anything for $60/hour, maximum one hour charge if they don't fix it.
He noticed that the mother board looked like it had an awful lot of
sockets, and that some of the chips didn't look well-seated therein.
He took them all out, cleaned them, and put them back in.

I should have thought of that.  Maybe it's just as well, because I
don't have the insertion tools they used in the shop.  Anyway the
result is that the machine is once again solid as a rock.

Moral: take the case apart, and at least push on all the socketed chips.
Push pretty firmly, but don't break the motherboard or anything.
If you're up to it, it might be best to take the motherboard out completely,
and push on the chips with the board on a padded surface.  It takes an
hour or so to get the motherboard out and back in; there's all those
spacers and screws to take out, and you have to take out a bunch of the
connector hardware on the back.  I forget the details.