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:
- Make sure the | / 0 power switch at the rear of the power supply unit is in the l position.
- 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.
- Replace the power cord with another known good cord. This is the same type of cord your monitor uses.
- 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.
- Try plugging the cord directly into the wall. Do not use power strips as they may have failed.
- Toggle the voltage regulator switch from 115V to 230V then back again. If you are in North America, this switch must be on 115V.
- 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.
If your PSU has an indicator light
- Indicator light should be solid and not flashing.
- If the HP power supply is flashing, disconnect everything inside. If the LED is still flashing, the power supply is probably bad.
- If the LED is completely off, then the power supply is probably bad.
If you have any other questions about power supplies, please visit our computer repair message board.
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{ 21 comments… read them below or add one }
the blue light on the charging led in on . not flushing , but the computer still not charging neither working
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.
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?
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.
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
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.
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?
Hopefully it is the power supply. The clicking sound is odd, but with a surge, the power supply usually takes the hit.
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?
http://h10025.www1.hp.com/ewfrf/wc/document?lc=en&cc=us&dlc=&product=89876&docname=bph06788
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
Joe, you should join our forums at http://www.pctechbytes.net/forums/ and we can troubleshoot this further. It doesn’t sound like the power supply if the diagnostic light is not out or flashing.
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.
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.
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.
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?
Not so much the low voltage, but a spike after the brown-out could damage it, sure.
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.
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.
I have had 4 hpe 137c pcs in the last month and a half and had to return because the power supply keeps burning out.one of them only lasted four hours we have never had problems with power surges before and they have all bean on surge protectors the last one ona brand new one. I have three other computers that have no problems.Is there a problem with this model or can i be doing something wrong. All have come from Sam’s Club.
I have a hp pavilion a814x. Computer tower will not turn on. The psu indicator light is flashing. When I disconnect the main cable that leads to the mother board the light stops flashing and remains on. Is this a problem with the mother board or could it be the psu?