No Power P8 side?

By thewolfe
Dec 18, 2002
Topic Status:
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  1. No power?

    No power?

    I have a P-133 that I tried to add a second (slave) HD to. I plugged in the power and ribbon cable and tried to start up. Heard a little noise. Very faint, can’t describe it. Turned the power of and on again, no faint noise.

    Waited a minute, turned the power on, heard faint noise………same as above.

    So I figured I fried the power supply, so I replaced the power supply and no power.

    No I wonder if the original was ok but something else was happening.

    I will get a multimeter and check both power supplies, but what else should I look for?
  2. conradguerrero

    conradguerrero Newcomer, in training Posts: 357

    well if you unplug your new hard drive and then turn on your computer you will know if your power supply is broken or was just overloaded. Do you have a lot of things running?
    :confused:
  3. thewolfe

    thewolfe Newcomer, in training Topic Starter Posts: 287

    I'll try that and I don't understand "a lot of things running".
  4. thewolfe

    thewolfe Newcomer, in training Topic Starter Posts: 287

    Let me make sure...

    Let me make sure I'm doing this right before I toss my power supply.

    I plug the P8 & 9 connectors into the mobo, black wires on the inside together.

    Plugged in the power cord to the computer and put the black lead to the black wire and the red lead to the yellow wire (down in the connector). No reading.

    I don't have all the other connections that power the hard drive, etc. But I assume I don't need to do that to test voltage.


    Still don't know why the other power supply didn't work although some of the connections were a little different.

    Also I didn't test the second PS although it was working in the other machine a hundred years ago.

    Also checked the fuse.

    Anything I did wrong or should try?
  5. StormBringer

    StormBringer Newcomer, in training Posts: 2,871

    You say some of the connections were a "little different" explain this. When you checked the fuse, was this a visual inspection, or did you check it with an Ohm-meter to be sure? Sometimes a fuse can blow and still appear to be fine.

    What was the old PSU rated at and how many devices are in the machine?

    Is the voltage selector on the PSU set on the right voltage?
  6. thewolfe

    thewolfe Newcomer, in training Topic Starter Posts: 287

    The orig power supply has a female connector to the HD with a male at the end of that that connects to the power supply. Also on that connection is a wire that goes to a heat sink fan.

    On the second power supply there is no wire to fan.

    I only checked the fuse visually. How would I check it w/ my multimeter?

    250w and only have CD ROM, floppy and HD.

    I had voltage selecter set to DC w/ a "v" under it.
  7. StormBringer

    StormBringer Newcomer, in training Posts: 2,871

    To check the fuse with a multimeter, just set the meter to test Ohms, then put one lead to one end and the other lead to the other end of the fuse, if it reads as a short, then it is good, if it gives no reading or reads open, then it is blown.

    On the Voltage selector, I meant the one on the PSU not the meter. There is a switch on the back of most power supplies that has marked 115 and 220 or something similar, it may say 125 and 230. You have to set it to the correct line voltage for your outlets.

    What were the voltages you read off of P8 & P9?
  8. thewolfe

    thewolfe Newcomer, in training Topic Starter Posts: 287

    Sorry, 115v.

    I get nothing.
  9. thewolfe

    thewolfe Newcomer, in training Topic Starter Posts: 287

    Also, to check the fuse do I need the psu plugged in. Sorry, some of this is beyond my scope of experience.
  10. StormBringer

    StormBringer Newcomer, in training Posts: 2,871

    When checking the fuse, the PSU should be off and best if unplugged. You'll either blow the fuse in your meter or cause damage by using the Ohms setting with power supplied. If possible, remove the fuse and check it out of the circuit.
  11. thewolfe

    thewolfe Newcomer, in training Topic Starter Posts: 287

  12. thewolfe

    thewolfe Newcomer, in training Topic Starter Posts: 287

    OK. I checked my "bad" power supply in another machine and it boots up. Sorry bout that. Should have done that a long time ago, but live and learn.

    Now what should I check.

    Remember , the only thing I did orig was to try to add a "slave HD.
  13. thewolfe

    thewolfe Newcomer, in training Topic Starter Posts: 287

    I will do that again.

    Also, the other good PSU that I just tried makes a faint buzzing sound that sounds like it may be coming from the PSU but it's had to tell. It sounds like a fly flying around inside that you can barely hear.

    It's definitely coming from the side of the computer with the HD and PSU.
     
  14. Mictlantecuhtli

    Mictlantecuhtli TechSpot Evangelist Posts: 4,916   +9

    Sounds like a short circuit somewhere to me.
  15. thewolfe

    thewolfe Newcomer, in training Topic Starter Posts: 287

    When I re-installed the orig PSU back, the "buzz" is definitely coming from the orig PSU.
  16. Nodsu

    Nodsu Newcomer, in training Posts: 9,431

    Maybe your new hard drive is having a short cirquit somewhere?
    Try it in another computer, if you fry the PSU or the drive just doesn't work the it should be pretty clear.

    I suppose you could try the ohmmeter on the drive inputs too.
  17. StormBringer

    StormBringer Newcomer, in training Posts: 2,871

    Buzzing sound from PSU, sounds like an overloaded transformer. Though some older PSUs and even some newer cheap ones make a faint buzzing even when they are fine. Since you are having problems, I would suspect this may be the fault.
  18. thewolfe

    thewolfe Newcomer, in training Topic Starter Posts: 287

    No Power P8 side?

    Tried to install a "slave" drive on my P-133 with AT PSU.

    Wouldn't boot. Disconnected "slave".

    Discovered that the P8 connection on the mobo is the culprit, I think.

    With no power to all drives and the CPU fan connected directly to the PSU nothing runs. If I disconnect P8 from the mobo the fan starts.

    What now?
  19. thewolfe

    thewolfe Newcomer, in training Topic Starter Posts: 287

    No Power P8 side?
    No Power P8 side?

    Tried to install a "slave" drive on my P-133 with AT PSU.

    Wouldn't boot. Disconnected "slave".

    Discovered that the P8 connection on the mobo is the culprit, I think.

    With no power to all drives and the CPU fan connected directly to the PSU nothing runs. If I disconnect P8 from the mobo the fan starts.

    What now?
  20. iss

    iss TechSpot Chancellor Posts: 2,896

    what make of computer is this? some makers use proprietary motherboard hook ups. I had a dell that used a P7 connection to the motherboard and you couldnt use just any power supply because the connector was actually reversed from those on standard power supplies and motherboards. ( Dell's way of trying to make you buy from them)
  21. StormBringer

    StormBringer Newcomer, in training Posts: 2,871

    At this point, I'll ask the first question I should have asked.
    What brand of PC is this? Some PCs have proprietary PSUs.
  22. thewolfe

    thewolfe Newcomer, in training Topic Starter Posts: 287

    This is a clone I'm trying to fix up for a "newbie" and the power supply it the one I got with it.

    It was working OK until I tried to hook up a "slave" HD.
  23. thewolfe

    thewolfe Newcomer, in training Topic Starter Posts: 287

    It's a clone and this is the orig PSU which was OK until I tried to hook up a "slave" HD.
  24. StormBringer

    StormBringer Newcomer, in training Posts: 2,871

    OK, I thought it might have been the replacement PSU. I also wanted to make sure you weren't trying to use it in a Compaq or HP, most of them use proprietary PSUs.

    Anyway, if you are getting no voltages on P8, then it is very possible that the PSU has problems. If this is the same PSU with the buzzing then it would likely confirm my theory of a faulted transformer.

    I am still wondering why the other PSU would not work. This leads me to think there may be a problem elsewhere which possibly caused the PSU problem.
  25. StormBringer

    StormBringer Newcomer, in training Posts: 2,871

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