Power supply LED light flashing after power disconnect - PC does not start anymore

[hediezz]

Hi,

I recently had to move my PC. So I made a proper shutdown, disconnected the power plug, and moved the PC.

When I reconnected the power plug, the PC did not start anymore, the power supply was "tikking" and the green led flashing. I followed the HP support guidelines to identify the problem, it suggested various scenarios from dead power supply till dead motherboard. However, when I disconnected all power supply connection in the PC, and reconnected the power plug to the power supply, the LED turned to steady green again. If I reconnected all power connectors into the PC, the LED started to flash again.

I googled and found on the web various people having faced the same problem and solved it this way:

1) unplug the power cable

2) unplug the power connector from the motherboard

3) re-plug the power cable into the power supply

4) when power still on, re-plug the power connector on the motherboard

By following this (scary) procedure, the led light remained steady, and my PC restarted normally.

Although I am happy that this empirical approach solved the problem, I am still looking for a technical analysis of the problem and its resolution. Root cause? Any help would be welcome.

Kind regards,

Hezz

[jsudds]

Hi,

I am currently experiencing the same problem.  I shut down and unplugged the computer while away on vacation and when I returned I now have the flashing and ticking LED light but the PC won't start up at all.  I suspect it may be an issue with the power supply unit (PSU), but haven't confirmed that yet.

Can you please share the link(s) for where you found those instructions on the web?

Also, in step 1) when you say to "unplug the power cable," which power cable are you referring to?  The one from the wall to the PC?  Or something on the PSU itself?

Thanks!

[kfeeser]

This is really not something you should try unless you have done a hard reset (holding the power button down for thirty seconds, then doing the same thing with the battery and ac power disconnected), but I found with my old HP laptop that when I removed the cover to the CPU/Processing unit (not the hard drive cover) and took out the small, circular shaped battery and replaced it, everything was okay again.

Look for the manual on where yours is.

[alshoemake]

Most of these I've run into have shorted or leaky capacitors on the motherboard.  Open the cover and inspect all the electrolytic caps i.e. the tubular components, especially around the processor.  You will probably notice they are bulging or have corrosion around them.  Unplugging the main mobo power supply connector, applying power to the power supply and then reconnecting the main power supply connector either bypasses the leakage test or temporarily clears the leaky/shorted cap(s).  I wouldn't recommend doing this.  A diffierent power supply may solve the problem temporarily possibly because it may not check for leakage current prior to power up.  If the caps look bad - replace the mobo or have the caps changed.

[remcosteve]

Hello Hezz,

Your item #4)worked for me and fixed the HP Power supply problem, stopped the blinking LED light, and my computer fired right up.

4) with the power still on, re-plug the power supply connector on the motherboard

In fact, I had to do it twice.  Since that time, I decided to back up my hard disk.  I don't know how much longer my 6 year old HP Pavillion will last.  It has been fairly trusty to date. 

As far as why it works,  my experience with black box electronics is that it always helps to reset the component if something locks up.  Maybe the electrical jolt by plugging in the mother board is enough to reset the motherboard.

Thanks for posting your results, it save me from having to get a new computer.

SAS

[abaum]

This solution also worked for me. Thank you for doing the research and posting it.

[jdroupp]

This solution worked for me to start up the computer.  However, when you power down or restart your computer, the same thing happens again.

This started with my HP P6110Y screen going blank eventhough the computer LED was still on.  The computer shut itself down. I keep re-starting the computer and same problem occurs.  I left the machine shut off for 1 hr, and that's when the LED on the PSU started flashing. I replaced the power supply and the same "shut down" problem still occurs.

I'm interested in finding out what causes this so I can fix it. As it stands now, it seems I will ned to replace the MoBo with the same exact part number (which is proving to be diffucult - as HP has discontinued the MoBo) so I don't have to re-install the operating system along with all the software.

I looked over the entire MoBo, and I have not identified any capacitors bulging or corroded.

Anyone know what is causing this?

[jdroupp]

I figured out that it was my BFG NAVIDIA (out of business) video card causing this issue with the power supply. Once I removed the video card, all is well.

[cqueendiva22]

Hello,

I currently have the same problem with my pc. When you unplug the motherboard does it erase the pc memory and everything you have stored?

[danielv]

No.  And from your question I would not recommend that you try to work on the computer before reading up on how computers work, what the main components are, etc 🙂