[unix-pc.general] Intermittant Bootup Failure: AT&T too much!

sitongia@hao.ucar.edu (Leonard Sitongia) (11/29/88)

With increasing frequency, my unixpc shows an intermittant problem in which
it wont boot.  The screen goes solid green (or bright green with a fine
black grid that makes it look like an array of small boxes, but not like
the line of small boxes at bootup).  Usually this is upon powering up the
box, but once it crashed with no messages and showed this symptom.  In the
past Ive tried the solutions to the "drive doesnt spin-up" problem, shaking
the box and cycling the power.  Eventually it is revived.  Other symptoms
are that the keycaps lock LED comes on briefly and the fan works.

Since this problem has been occuring with increasing frequency, I sent it
in to AT&T for repair.

Unfortunately, they want to replace the motherboard and some other board,
at a cost of $1400!  That's what I spent for it new!

So, Im going to have to try fixing it myself. 

Can you give me a hint on what part of the hardware may be at fault?  Is
the green-screen consistant with the "drive doesnt spin-up" problem?
Sure seems to me that this could be as simple as a loose cable or bad
solder connection...

Thanks for your help,
Leonard
-Leonard E. Sitongia    System Programmer		 (303) 497-1509
USPS Mail: High Altitude Observatory P.O. Box 3000 Boulder CO  80307
Internet:               sitongia@hao.ucar.edu
SPAN:			NSFGW::"hao.ucar.edu!sitongia"	[NSFGW=9580]

gil@limbic.UUCP (Gil Kloepfer Jr.) (11/30/88)

In article <1056@ncar.ucar.edu> sitongia@hao.ucar.edu (Leonard Sitongia) writes:
|>With increasing frequency, my unixpc shows an intermittant problem in which
|>it wont boot.  The screen goes solid green (or bright green with a fine
|>black grid that makes it look like an array of small boxes, but not like
|>the line of small boxes at bootup).  Usually this is upon powering up the
|>box, but once it crashed with no messages and showed this symptom.
|>-Leonard E. Sitongia    System Programmer		 (303) 497-1509
|>SPAN:			NSFGW::"hao.ucar.edu!sitongia"	[NSFGW=9580]

This sounds an awful lot like something Lenny (you all know, lenny@icus)
told me about a long time ago (he's at the SysV.4 developer's conference,
so I'll answer for him) -- Seems that this is SOMETIMES a bad 68010 processor.
If you have access to a spare, or feel like going out and buying one, it's
cheaper than what AT&T wants for a new motherboard (might as well just
buy another 3B1 and use it for parts ;-).

A suggestion I can give is to make sure all the chips on the motherboard
are seated properly in their sockets, and carefully vacuum the dust off.
If it's anything like the inside of Lenny's 3B1, you'll need to replace
the vacuum cleaner bag when you're done (sorry Lenny :-)!!  In any event,
intermittents are generally caused by this, a chip going bad, or a broken
trace on the motherboard (forget it!).  Also check the solder connections
to the power supply connector.

---------
Gil Kloepfer, Jr.          U-Net: {decuac,boulder,talcott,sbcs}!icus!limbic!gil
ICUS Software Systems      Voice: (516) 968-6860 [H]   (516) 746-2350 x219 [W]
P.O. Box 1                 Internet:  gil@icus.islp.ny.us
Islip Terrace, NY  11752   "Life's a ...  well, you know..."