djp@cs.brown.edu (Abdullah The Butcher) (07/01/90)
Hey folks. . .
I am new to this group, but since my mother's pc just died and I
have not been able to figure anything out, I figure this would be a
good time to start following it. Here's the deal:
Hardware is: IBM PC/2 (256k mother board), replaced power supply
(150W), EGA card, Enhanced Color Monitor, the original floppy
controller, 360k drive in right bay, 15M hard drive from Hardtimes in
the left drive, hard drive controller that came with the hard drive,
256k on mother board, additional 256k board to bring it to 512k,
parallel printer adapter.
Syptoms are: in the middle of working on a lotus worksheet,
everything hung. The computer has had sporadic problems on startup -
sometimes it just wouldn't boot until it was switched off and back on.
Once everything hung, mom gave up and turned it off. Since then, it
will not boot. Period. From floppy or hard disk. When it is turned
on, the hard drive led flashes, the led on the hard drive controller
card flashes, the power supply seems to kick in (the fan spins), but
it just never tries to read from either drive. The screen simply
shows white static.
Things I tried: it reeked of hard drive controller problems to me, so
I reseated the card. Nothing. I pulled it, hoping to boot from the
floppy. Nothing. Getting very annoyed, I pulled both drive
controllers, hoping to at least get the monitor to turn black and give
me an error number. Nothing.
So, I am left thinking it may be 1) a lame power supply that just
isn't doing the job. 2) some problem with the drive cables (not
likely, but it would be a nice cheap solution :-) ). 3) a problem
with the (gulp) mother board somewhere. Since seems somewhat likely
since I never get through a boot sequence.
All the same, I am very open to suggestions. What else might it be?
What other tests might I try to diagnose this? I will pull boards,
flip switches, etc., all night, but I can't logic probe/solder/do
other board/chip level maintenance. So please, help!! Mom is
panicking. It is pretty important, so answers to me personally would
probably work best.
Thanks!!!
Dave Pawson
djp@cs.brown.eduherrj@valnet (Jonathan R. Herr) (07/01/90)
> So, I am left thinking it may be 1) a lame power supply that just > isn't doing the job. 2) some problem with the drive cables (not > likely, but it would be a nice cheap solution :-) ). 3) a problem > with the (gulp) mother board somewhere. Since seems somewhat likely > since I never get through a boot sequence. > > Thanks!!! > Dave Pawson > djp@cs.brown.edu All three of your ideas are valid, but there is also the possiblity that it may be your BIOS ROM has gone bad on you. Since it is rather important on bootup, you might consider it, also. Finding out if this is the problem may be difficult, though. 8-( Jonathan R. Herr valnet!herrj herrj@silver.ucs.indiana.edu
rdu@cbnewsk.att.com (ranjan.dutta) (07/02/90)
In article <44260@brunix.UUCP> djp@cs.brown.edu (Abdullah The Butcher) writes: >Hey folks. . . >everything hung. The computer has had sporadic problems on startup - >sometimes it just wouldn't boot until it was switched off and back on. >Once everything hung, mom gave up and turned it off. Since then, it >will not boot. Period. From floppy or hard disk. When it is turned > >Dave Pawson Dave, Power Supply looks like the best bet. Before booting, PC checks for the stability of the power supply. If the power supply is flaky, it just might lay dormant. Hope it helps, Ranjan
wdarden@nrtc.nrtc.northrop.com (Bill Darden <wdarden>) (07/04/90)
In article <33DmL1w162w@valnet> herrj@valnet (Jonathan R. Herr) writes: >> So, I am left thinking it may be 1) a lame power supply that just >> isn't doing the job. 2) some problem with the drive cables (not >> likely, but it would be a nice cheap solution :-) ). 3) a problem >> with the (gulp) mother board somewhere. Since seems somewhat likely >> since I never get through a boot sequence. >> [Stuff deleted] Try doing the following assuming there are no beeps (or error codes) at start up. If there are beeps, note how many and duration. The beeps and error codes are used to indicate specific problems areas. Brenner's PC repair book published by Sam's will help you. 1. Check the DC voltages on the mother board for a bad power supply. 2. Reseat all of the socketed chips on the mother board. 3. Look a bad crystal by checking for clock pulses on pins 2,8 and 12 of the 8284 timer chip. Any one of a dozen chips being bad can cause a dead PC. I would not waste a bunch of time looking for a morther board failure becasue you can buy used Turbo XT mother boards with 640 KB on them between $50 and $100. Good luck, BiLL......
jearly@lehi3b15.csee.Lehigh.EDU (John Early) (07/04/90)
In article <1990Jul2.152841.27127@cbnewsk.att.com> rdu@cbnewsk.att.com (ranjan.dutta) writes: > In article <44260@brunix.UUCP> djp@cs.brown.edu (Abdullah The Butcher) writes: > >Hey folks. . . > >everything hung. The computer has had sporadic problems on startup - > >sometimes it just wouldn't boot until it was switched off and back on. > >Once everything hung, mom gave up and turned it off. Since then, it > >will not boot. Period. From floppy or hard disk. When it is turned > > > >Dave Pawson > Dave, > Power Supply looks like the best bet. > Before booting, PC checks for the stability > of the power supply. If the power supply is > flaky, it just might lay dormant. > Hope it helps, > Ranjan I missed the begining of this thread, so I don't know whose motherboard it is, but here are a few thoughts: mis-seated cards can cause this same probelem, as will a bit of metal falling into the case and shorting. I had a PC (DTK motherboard) which had a flaky keyboard connector and would shut down if you were too rough with it. Don't give up on the power supply just yet...try this: disconnect all the power supply connections to hard and floppy drives (and anything else) as well as the motherboad. Turn it on. If the fan runs the powersupply is fine, and the problem is (most likely) on the motherboard. Try shorting the power-good line to the supply and see if it boots then. Hope this helps, John. ---------------------------------------- John Early | jearly@lehi3b15.csee.lehigh.edu | I was just a child then; JPE1@Lehigh.Bitnet | now I'm only a man. [pf] LUJPE@VAX1.cc.lehigh.edu |
roy@cs.umn.edu (Roy M. Silvernail) (07/05/90)
jearly@lehi3b15.csee.Lehigh.EDU (John Early) writes: > Don't give up on the > power supply just yet...try this: disconnect all the power supply connection > to hard and floppy drives (and anything else) as well as the motherboad. > Turn it on. If the fan runs the powersupply is fine, and the problem is > (most likely) on the motherboard. That's not a 100% sure indicator. It seems that some (many?) switching power supplies will not operate at all unless loaded. Thus, pulling all the plugs on one of these will guarantee a "dead" supply. 2 of my supplies are of this type, and I was warned about this behaviour when I purchased them. -- Roy M. Silvernail | 'I don't see why you people | Opinions found now available at: | seem to think this is magic... | herein are mine, cybrspc!roy@cs.umn.edu | Its just this little chromium | but you can rent (cyberspace... be here!)| switch here...[click]' | them.