[comp.sys.ibm.pc.misc] Strange Problem -- HELP!

dchun@aludra.usc.edu (Dale Chun) (12/15/90)

We have a Leading Edge Model D2 Computer equipped with an Intel Above
Board/2 Plus 8 with a Deico Electronics Super-VGA board using the
Tseng Video Chips and the ET4000 controller. We also have a Toshiba
IDE 105mb hard drive. What happens is it boots just fine with the
cover off, but locks up with the cover on. We removed one of the
grounding clips and it seems reduce the amount of lock ups. Is this
safe and am I on the right track in removing the remainder of the
grounding clips to the case in hopes of solving my bootup problem? My
roomate tells me the new Toshiba hard drive is creating a grounding
loop (whatever that is) with the video card. Can someone explain this
strange problem?

Sorry, but I am getting desperate since bootup lockouts ain't fun. I'm
a software person, not hardware.
					...dale

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 name: Dale C. Chun	    | * 2 + 2 = 5, for sufficiently large values of 2.
PLAYMAC Technical Support   | * Hack First, Ask Questions Later.
email: dchun@aludra.usc.edu | * MAC; Maybe A Computer, but probably a toy.
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v087mxgb@ubvmsa.cc.buffalo.edu (Shawn E Thompson) (12/15/90)

In article <13679@chaph.usc.edu>, dchun@aludra.usc.edu (Dale Chun) writes...

could be (never heard of a grounding loop......sounds like
imaginary technobabble :-)    )

its so hard to make conjecture sight-unseen, BUT....

I've had TWO similar prob's ...AND I also use an
above board (and an inboard).


First time, a ribbon cable was at fault.

Second time, board had a short in it. When the cover
was screwed in place, it was applying load to the 
board, and flexing it (minutely) enough to induce a
open circuit somewhere...


SUGGESTION, try putting the cover in place, WITHOUT
tightening, that way the ground will still exist,
but you can check for a MECHANICAL cause........




best I could do :-&       (thats a sheepish grin sideways)

Shawn E. Thompson "..my sig file was so long, I'm not even allowed a quote..."
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