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Strange problem for you hardware gods...

Discussion in 'Bits & Bytes' started by Ravenink, Dec 27, 2002.

  1. Ravenink

    Ravenink Veteran Member

    I just had the weirdest call of my life....I am up for ideas, as I'm totally stumped by this one, and odds are this is going to be on my desk on monday again since my group has to deal with all the truly strange issues.

    Ok, here is the problem:

    system has two primary problems, won't read from the floppy, and the keyboard doesn't work. This system at this time has no OS on it, so these problems exist on BIOS level. First, we tried to isolate the keyboard issue. Tried different keyboards, didn't work. This is a ps/2 keyboard so there isn't any real driver loading to do in order to have it work during boot. Odd, but we decide we'll deal with that later and try to get the floppy drive working. We try a different floppy disk, nope, try a known good floppy drive...nope, try another floppy cable...nope. Out of curiosity we clear the CMOS on the board. After clearing the CMOS, the floppy drive not only doesn't read, but gets no power at all. Why clearing the CMOS would cause the floppy to get no power, I have no idea. Either way, we figure it's a weird system board, so we order another.

    Today we put in the new system board. It has the same exact problem. We go through the same tests with the same results. This time we build it outside the box. It sounds strange, but sometimes if the case is damaged it can short out the system and make it do odd stuff. Well, we build the system outside the box, and it doesn't change a thing. So we put it back in the box. Well, once it is in the box, we try to start it up again. This time the box starts frying. A beautiful puff of black smoke arises from the system along with a burning smell. Well, since it is obviously not the system board causing the initial problem, we put the old system board back in. Old system board acts just like it used to. System still does not have a working floppy or keyboard.

    At this point, since a board got fried and the floppy could be a power issue, we put in a new power supply. Now with the new power supply we still do not have a working floppy or keyboard. I'm stumped. Any ideas? (btw, my current plan is to do an exorcist on the machine, I suspect it to be posessed.)

    btw, machine has been taken down to bare bones, same problem exist.
  2. midranger4

    midranger4 Banned

    bad ribbon cable(s) causing a short?

    Sounds like you've tried just about everything else.

    Let us know what you find to be cause of this one, it truly is a strange one.
  3. Sierra Mike

    Sierra Mike The Dude Abides Staff Member

    Good God...throw the chassis out and buy a new one!

  4. Coot

    Coot Passed Away January 7, 2010

    It may have been a bad power supply all along, I assume you didn't check voltages, that may have toasted both boards.

    As you note later that on a subsequent try that the floppy also had no power, how did you notice this? Was the floppy LED on all the time on earlier tries? If so, the floppy cable may have been installed upside down at the drive end...it is possible to do this, however when I've seen this done, the keyboard would still work.

    You did not mention whether the board tried to POST. If it did not, then there's several other options to check.
  5. tke711

    tke711 Oink Oink Staff Member

    I think I'd go with the exorcist as well Raven.

    This has me stumped as well.
  6. Ravenink

    Ravenink Veteran Member

    the board does post. have tried a different cable, to no avail. I didn't check the voltage before putting it on the new system board, no. I usually don't have to be that cautious :) I did notice that the floppy had no power by its lack of light, but it was not on all the time previously. it was only on when trying to read from the floppy. the same symptom that occured on the old system which had worked for about a year.

    thanks for all the help so far guys :)
  7. Coot

    Coot Passed Away January 7, 2010

    I've seen a hosed CMOS do some very similar things to that. The board tries to POST, but only recognizes some components. What board is this?
  8. Ravenink

    Ravenink Veteran Member

    it's an IBM board, in a 6862 machine type.
  9. mrRT

    mrRT Tech Mod

    +/-5V or +/-3.3V or the +/- 12V rail is shot....Powersupply issue

    A better question for you is why did the supply go...is there a short on the board that caused the short...

    now the fun begins....

    my course of action would be the following

    use a known good PS.
    unplug all connections to devices, except for main supply to board
    be sure board posts correctly.
    power off
    connect floopy
    check boot to floppy for keyboard
    no power to floppy..change cable

    still no boot to floppy remove board and recheck..
  10. -Ken

    -Ken Guest

    I'll tell you what I'd do...

    Pull the RAM, CDROM drive, hard drive, CPU and reassemble all those parts in a new barebones system.

    For a case, power supply and motherboard you are looking at $75-$90, dollars depending on the speed of the CPU. Oh yes, why not buy them a new floppy drive while youre at it for $7.50.

    I would also give the owners the choice of a cheap upgrade instead of the repair.

    In this case, a barebones Athlon XP2000 will set you back $125.00 delivered. Assemble all the parts into the case, charge your clients $150.00-$200.00 and sell the remaining parts to cover your time and profit.

    The customer will be thrilled with their new (and much faster) system and you look like the hero for giving them an option instead with sticking them with a bill from the machine from hell!
  11. Misu

    Misu Hey, I saw that.

    I don't know if this will help anyone, but I had a very similiar thing happen to me on my old little computer, and after hours of trying to fix it myself, asked hubby to help. He told me to buy new ram. When I installed the new ram, the problems went away. He then told me that bad ram will do weird crap to your computer.

    I don't think that'll work, but heck, it's an excuse to add more memory :)
  12. Ravenink

    Ravenink Veteran Member

    mrrt: thanks for the advice. I have already tried the system with just power supply, sysbrd, and processor. it does post. connecting the floppy, does not work however. still gets no power. tried switching cables to no avail.

    Ken: trust me, if I was working privately with the customer I would, but since I work the manufacturer of the PC (one of the big blue giants *hint*) I can't :p
  13. Coot

    Coot Passed Away January 7, 2010

    Well, that's your problem...you need to get a real motherboard ;)
  14. jamming

    jamming Banned

    Has the Floppy been tested? Could be a bad Floppy, its rare but does happen.
  15. Ravenink

    Ravenink Veteran Member

    yes, floppy has been tested both by putting it on a working machine and taking a known good floppy from another machine and putting it on there to no avail.
  16. jamming

    jamming Banned

    When we had a board hit by lighting it sizzled real good when we tried turning it back on. I played around with it on the bench and found that its powersupply had problems, and also the board had problems separately. Connecting a new PS to the board and Connecting the new board to the old PS, both would kill the new item. You may have two faults instead of only one.

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