Troubleshooting an HP Power Supply

| August 1, 2009

Troubleshooting an HP power supply can help you determine if your computer’s problem is the power supply or the motherboard. If your Hewlett-Packard PC is experiencing power issues, it’s quite possible there may be a problem with the Power Supply Unit (PSU).  The power supply is inside the PC and is exposed at the back of the computer.  The external view of the power supply shows the cord that goes to the wall socket and will often have a l / 0 switch and a red voltage regulator switch that indicates 115 and 230.  Some HP models will also have an indicator light. Try the following to troubleshoot the power supply:

Tips For Troubleshooting An HP Power Supply

  1. Make sure the | / 0 power switch at the rear of the power supply unit is in the l position.
  2. Unplug the power supply at the rear of the PC, and then press the power button on the front of the unit.  Plug the power supply back in and see if it works.
  3. Replace the power cord with another known good cord.  This is the same type of cord your monitor uses.
  4. Clean the unit.  You can vacuum or air-blast the outside of the unit to remove dust and hair debris.  Vacuuming the outside is preferred as blowing will cause the debris to go into the power supply.
  5. Try plugging the cord directly into the wall.  Do not use power strips as they may have failed.
  6. Toggle the voltage regulator switch from 115V to 230V then back again.  If you are in North America, this switch must be on 115V.
  7. Lastly, you may need to go inside the case and confirm the thin wires running from the front power and reset switches are connected to the motherboard.

Troubleshooting an HP Power Supply – Power Supply Indicator Light

Troubleshooting an HP Power Supply

Troubleshooting An HP Power Supply

  1. Indicator light should be solid and not flashing.
  2. If the HP power supply is flashing, disconnect everything inside.  If the LED is still flashing, the power supply is probably bad.
  3. If the LED is completely off, then the power supply is probably bad.

Other Resources:

Blank HP Monitor

HP Recovery in Windows Vista

Category: HP

Dave

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Dave has been providing free computer repair and tech support advice online since 2002. Join us on our forums and be sure to subscribe to our newsletter for weekly tips and other helpful computer articles. Connect with me on: Google+

Comments (22)

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  1. ilyas says:

    the blue light on the charging led in on . not flushing , but the computer still not charging neither working

    • Dave Dave says:

      I’m not sure I follow you, but it sounds like a laptop and either the power supply cable is bad or you have a bad connection on the motherboard itself that will need to be fixed or replaced. Good luck.

  2. Norm says:

    I have an older HP, XE743, but I’ve upgraded the hard drive, OS, and RAM. I replaced the hard drive, 40 G, with 2 80 G drives. I’ve replaced the RAM from 64 to 512. Also, I changed the OS to Windows XP Pro. When I did the upgrades everything worked as should. After 9-10 months later I’m experiencing problems with the computer not powering up. When I push the button to turn on I get nothing. Now, I think someone has turned the computer off using the wall light switch and not shutting down it down the correct way. Could this effect the power source? Because this is an older computer has the power supply quit and needs replaced. I also want to add that this has happen in the past and the weird thing is after the computer has set for a few days, I push the on button and it starts up and boots as it should. Any suggestions?

    • Dave Dave says:

      Next time this happens, hold the power button in for twenty seconds, then try and power up again. This drains the capacitors of stored up electricity. I suspect this is why the machine boots after a few days–the capacitors have drained. If it begins to work normally, this is probably a motherboard issue.

  3. consuelo says:

    I recently was unable to get my Gateway to power up and took it to someone who insisted it was the power unit and replaced it with a used one. The next day I used it for several hours but the following day it again refused to power up… I have a new APC 550VA back up system and am at a loss…perhaps this guy I keep trusting really doesnt know what to do…If I had some type of irregular electrical surges in my home would the power surge unit not protect my computer? please advise…thanks

    • Dave Dave says:

      A UPS system might not protect you from spike. They do help with low power situations, such as power failures and brown-outs. You might want to invest in a new power supply, not a used one. I would also get a name brand, such as Antec.

  4. Kelly says:

    I have a compaq that is about 7 years old. We had a power outage yesterday and now it will not turn on. It is getting power from the power cord, but when I hold in the power button in, it clicks and the power switch leds flash and the fan turns just a hair all in rhythm with the clicking. Click, click, click… If I let go of the button everything stops. Do you think it is the power supply?

  5. allison says:

    I have an HP about 5yr old that runs great. The power on button on the cpu was getting a little touchy but worked. Until last night when I went to turn my machine back on and ….nothing. Green power light (on back of machine) is on but flashing. Will try unplugging everything on the inside when I get home today. Any other ideas?

  6. joe says:

    I have a newer HP a few years old and I pulled everything off as advised and plugged the power cord in by it self and the led on the power supply lights up and no blinking with it, could this still be a power supply problem, my kids unplugged it by mistake and it never came back on again .Thanks

  7. Jim says:

    I have an HP n7530s Slimline case and the power button at the bottom front will not “CLICK” on at times. Can this button be replaced – it looks like it comes out pretty easy, but where can I find a replacement. System works great when it CLICKS on but I am missing the CLICK from time to time so I am assuming it is a bad or going bad button.

  8. jeannette says:

    I think my power button has gone out, but how do I know for sure. The green light on the back stays on, but when I push the button on nothing happens. If that’s it how do I get to it and how do I buy a new one.

    • Dave Dave says:

      It’s hard to say whether it’s the power button or not. It’s very unusual for a power button to fail. The light you see may indicate the power supply is good, but the problem could be a bad motherboard. You might want to have a local shop look at it. Or you can join our forums and we can try and help you troubleshoot it further.

  9. mike says:

    i have an hp 7011 series and the power supply burned out a week ago.. purchased a new one and that lasted three days. I did notice the lights dimming during the rainstorm.. would low voltage take it out?

  10. Sheryl Rogers says:

    why does my hp computer sound like its running hot. every few minutes it sounds like a fan comes on and i’m not sure if the computer is ok or not. it runs fine.

    • Dave Dave says:

      I could very well be running hot. I would invest in a can of compressed air and make sure all intake and exhaust grills and fans are clean. If you’re handy with computers, you can even open it up and give the CPU fan a quick shot with air. Depending on the location of the computer it might be dirty inside.

  11. John says:

    I have an HP m9040n. My power supply was blinking and clicking and the computer wouldn’t turn on. I opened it up and unplugged the motherboard from the PSU, and when I plugged the power supply into the wall the light became solid again. If I plug the motherboard into the PSU while it is still plugged into the wall, the light stays solid and the computer boots up fine. However, if I unplug and then replug the cable from the PSU, the light starts blinking and clicking again until I do the process over. Is this a problem with the PSU or the motherboard?

  12. clarkent says:

    For some time after mains fail unable to power up, unless i temporaliy disconnect the cable from the PSU to the mother board. This has worked up till now, but not any longer, now Ive found if you do the PSU check by shorting out term 14 green wire with any ground wire, black, the fan on the PSU should start if OK, This test has been documneted in various tips, try this with the cable disconnected from the mother board firstly but dont leave to long as there could be a prob without any load on PSU.
    If the mains goes off, I now short the wires as above with the cable plugged in, fan starts, I then press the normal on button, PC starts to powers up, remove short circuit and Im OK till next ,mains failure. Dont know how this works I gather its the failure of the start up signal to the PSU. Ive actually intercepted the green and black with two wires to go to a small switch so I can reset when the power gos off, Works for me

  13. David Faustrum says:

    First I started to have trouble with my picture and then my computer would crash. Thought it was the graphics card but over night it would work fine for a couple of hours. It’s an Hp and the green light on the back is on and not blinking. Replaced power cord and worked for 2 days and now won’t turn on. Not sure if after market power supply’s will fit because they are all different sized and wanted something more powerful.