Pavillion desktop won't power up

[Chaplain_Bill]

I have a Pavillion p6-2100 series, Win 7 home pro.  

Everything was working fine, but I thought the power supply fan had stopped because I couldn't feel air moving.  I bought a replacement power supply and installed it.  In order to remove the old power supply, I had to take the motherboard loose from the chassis in order to get a tiny screw holding the power suppling.  I disconnected only the cable leading to the case fan from the motherboard.

I reinstalled the motherboard, the power supply and the power cables to the drives and motherboard.  When I tried to power the machine back up, it appeared the onboard video card had gone bad as the monitor wouldn't work.  The machine recognised the keyboard (lighted) and in about 30 seconds shut itself off.  I tried this a couple of times, same result.

I reinstalled the original power supply and got the same results.  Figuring the new power supply had smoked the motherboard completely, I purchased and installed a refirb motherboard, moving the existing CPU to the new board.

When I tried to power up, the lighted keyboard blinked once, the case fan started rotating and then stopped and that was it.  I've reseated all the cables, reseated the CPU and still, just that one second sign of life.

I doesn't seem likely that the power switch went bad.  What do I do next?  I don't really have the money to buy a new machine (and I don't really want to go to Win10).  I don't want to send the money for a new CPU if that's not the likely problem.

Replacing both the motherboard and the CPU messes with my Windows license if I remember correctly.

Thanks in advance for any words of  wisdom, encouragement, and/or condolences.  🙂

[Jeet_singh]

@Chaplain_Bill,

Thank you for visiting the HP Forums! A great place where you can find solutions for your issues with help from the community! I understand you are having issues with the computer no longer powers on. Don't worry I'll be glad to help you.

After reading your post, this definitely looks like a possible hardware failure with the PC. I would personally suggest you contact our HP phone support for available service related options.

HP Technical Support can be reached by clicking on the following link: http://h22207.www2.hp.com/us-en/?openCLC=true

(1) Once the support page opens please select the country in which you're located. Next, enter your HP model number on the right.

(2) Next, choose the 'Contact Support' tab at the top and scroll down to the bottom of the 'HP Support- Contact' page to fill out the form provided with your contact information.

(3) Once completed click the 'Show Options' icon on the bottom right.

(4) Lastly, scroll down to the bottom of the page and select 'Get the phone number.' A case number and phone number will now populate for you.

If you have any troubles, let me know and I will do my best to help!

Hope this helps, for any further queries reply to the post and feel free to join us again

Feel free to post your query for any other assistance as well,

It's been a pleasure interacting with you and I hope you have a good day ahead.

If you wish to show appreciation for my efforts, mark my post as Accepted Solution.

And click on the Purple Thumbs up icon at the bottom of my comment.

Regards,

[mdklassen · Accepted solution]

Your computer: HP Pavilion p6-2100 Desktop PC Product Specifications

 has the AAHD2-HY (Holly) motherboard.

For all the power-supplies that I have replaced, I have never had to (partially) remove the motherboard.

But, of course, Your Mileage May Vary.

> I reinstalled the original power supply and got the same results. 

> Figuring the new power supply had smoked the motherboard completely,

> I purchased and installed a refurb motherboard, moving the existing CPU to the new board.

The power-cables on most power-supplies have a 4-pin connector that must connect to a 4-pin socket near the CPU.  From the image above, see the "white-coloured-2-by-2" socket "down-and-left" from the CPU socket.

If you have not reconnected that power-cable, then the symptom could be a "power-off" a few seconds after "power-on".

> When I tried to power up, the lighted keyboard blinked once, the case fan started rotating and then stopped and that was it. 

> I've reseated all the cables, reseated the CPU and still, just that one second sign of life.

Disconnect the data/power cables from the disk-drive and the CD/DVD drive.

Disconnect all USB devices (printers, web-camera) including the mouse.

Leave the keyboard attached.

Then, try a "power-on".

> Replacing both the motherboard and the CPU messes with my Windows license if I remember correctly.

Changing only the CPU is not enough for the Windows Activation technology to invalidate your license.

Replacing the motherboard might be enough to invalidate your license.

Replacing the power-supply has no effect on the license.

[Chaplain_Bill]

Ding Ding Ding Ding

It was that power connection that I hadn't remembered I'd disconnected when I replaced the mb.  I *knew* it had to be something simple and I'd looked at that connector several times, but it just didn't register.

In the beginning... there were the four screws in the power supply accessbile from the outside of the case.  Then I found a very small screw inside the case going into the bottom of the power supply.   It was very close to the bottom and back sides of the case and the only way I could see to get a screw driver on it was to take the motherboard loose.  (It was at the extreme bottom left of the pic you posted.)

Thank you mdklassen, you made my day!