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Tutor
Posts: 12
Member Since: ‎04-25-2009
Message 1 of 5 (5,114 Views)

Pavilion d4999t will not power on after power failure

After a general power failure last night, my HP Pavilion Ultimate d4999t CTO will not power on. The LED on the power supply is green, but pressing the power button on the front of the chassis does not start the computer. I have unplugged the computer and let it sit for 10 minutes, then tried again.

How do I determine whether I need a new power supply or the motherboard has been damaged? Is this something only a technician can find?

Thanks,
-stephen
Washington DC

 

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Provost
Posts: 26,880
Member Since: ‎07-17-2009
Message 2 of 5 (5,085 Views)

Re: Pavilion d4999t will not power on after power failure

[ Edited ]

Hi,

 

Try the following procedure and see if you can isolate the issue.  Don't skip any steps.

 

 

 Trouble Shooting Power Supply Issues.

HP laptop 17t u100,
HP Photosmart 6520 and HP Deskjet 1112
Custom 1151 socket Z270 Intel i7-7700k @4,600 Mhz, 16GB Corsair 3000 Mhz dimms
Corsair H75 water cooler, Corsair CS 650M power supply
RAID 0 (dual Samsung 960 EVO m.2 240GB) boot system
Dual Samsung 840 EVO SSDs 500GB data storage, Intel 750 PCIe SSD 400GB
MSI NVIDIA GTX 980TI 6GB
ASUS ROG PG279q @144 MHz
Windows 10 and Windows 8.1 Pro x64 in UEFI mode
Tutor
Posts: 12
Member Since: ‎04-25-2009
Message 3 of 5 (5,073 Views)

Re: Pavilion d4999t will not power on after power failure

I followed all of the steps and still no joy. I discovered that even with the green LED, the fan in the power supply is not turning. I have ordered a replacement power supply by part number 5188-2859 or DLT350AB-8 A (seems to be a standard) from http://www.itwinkle.com/hp35posu51.html for $36 plus $11 shipping.

 

The power outage zapped one of my HP Media Vaults, too, and several nieghbors lost gear.

 

I'll reply when I have the new power supply installed.

 

-stephen

Washington DC

Provost
Posts: 26,880
Member Since: ‎07-17-2009
Message 4 of 5 (5,066 Views)

Re: Pavilion d4999t will not power on after power failure

[ Edited ]

Hi,

 

The fan in some of the new power supplies is thermally controlled.  I doubt that the HP PSUs are that sophisticated.  I hope tthe replacement PSU solves your issue.

HP laptop 17t u100,
HP Photosmart 6520 and HP Deskjet 1112
Custom 1151 socket Z270 Intel i7-7700k @4,600 Mhz, 16GB Corsair 3000 Mhz dimms
Corsair H75 water cooler, Corsair CS 650M power supply
RAID 0 (dual Samsung 960 EVO m.2 240GB) boot system
Dual Samsung 840 EVO SSDs 500GB data storage, Intel 750 PCIe SSD 400GB
MSI NVIDIA GTX 980TI 6GB
ASUS ROG PG279q @144 MHz
Windows 10 and Windows 8.1 Pro x64 in UEFI mode
Student
Posts: 1
Member Since: ‎05-30-2012
Message 5 of 5 (4,963 Views)

Re: Pavilion d4999t will not power on after power failure

[ Edited ]

Here's what worked for me to get the system to boot.

 

  1. Unplug power cord from the wall
  2. Then unplug the motherboard p1 connector (that is the big connector from the power supply)
  3. Wait 5 minutes until green light stops flashing, allows capacitors to discharge, and magic happens
  4. Plug the power cord back into the wall and it should now have a solid green light on the back. 
  5. Now plug in the motherboard connector. Yes , apply power first, then connect the motherboard
  6. Power on the system!

I forgot to mention, this all started after an unplanned power outage.

 

The only problem, every time I unplug the computer, I have to do this procedure to make it boot again. Shutting down the computer normally, and leaving it plugged into the wall, I have no issue.  Any thoughts on whether this is a motherboard issue, a power supply issue or something else?

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