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HP Pavilion a6600f desktop PC not communicating with monitor

Our HP Pavilion a6600f desktop PC (with 64-bit Windows Vista OS) has stopped communicating with its monitor.

 

The boot process seems to run for 7-8 seconds before stopping.  We can hear the fans and CD unit spinning during this time.  There are no alert beeps. 

 

We switched monitors to rule-out a monitor problem.  The two monitors we have attached to the case have both powered down before the boot process stops - possibly indicating no input received. 

 

We have tried to reset the BIOS blindly according to instructions provided elsewhere in this forum.  We also tried booting off a CD to no avail.  Please advise.

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Paul_Tikkanen
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Member Since: ‎07-13-2010
Message 2 of 11 (4,360 Views)

Re: HP Pavilion a6600f desktop PC not communicating with monitor

Hi:

 

It sounds like the video adapter went out.

 

If you have an add on card and integrated video, remove the add on card. Plug the video cable into your integrated video port and see if you get video.

 

If you do not have an add on card, you may have to buy one (PCIe x16 video adapter) in order to have video again.

 

See if you can borrow a PCIe x16 video card from someone to try before you go out and buy one.

 

Paul

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Message 3 of 11 (4,359 Views)

Re: HP Pavilion a6600f desktop PC not communicating with monitor

Thanks for the response, Paul.  Unfortunately, this model's NVIDIA Geforce 7100 graphics interface is integrated onto its motherboard.

 

Our other computers are all laptops or older style models, so temporarily borrowing one is not a quick option - albeit I expect it is a likely resolution to the problem.

 

Any other ideas out there?

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Message 4 of 11 (4,352 Views)

Re: HP Pavilion a6600f desktop PC not communicating with monitor

Here is a quick update...

 

We picked up a new graphics card for the Pavilion's PCI slot, and it mounted just fine.  Unfortunately, we are having the exact same problem after this $50 attempt to fix it.

 

I am now focusing on the lack of activity after the initial 7-8 seconds during which the lights on the CD drive blinks.  I think the BIOS is not even booting.

 

Any thoughts on this problem?

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Paul_Tikkanen
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Message 5 of 11 (4,345 Views)

Re: HP Pavilion a6600f desktop PC not communicating with monitor

Hi:

 

Wow. I don't know. Now it could be either the power supply or the motherboard that could be the cause of the problem.

 

But first, do the poor man's test on the memory.

 

If you have more than 1 memory chip, remove one and start the PC and see if anything changes. If not, remove the other one and replace it with the one you had previously removed.

 

Sometimes the memory can go out.  But I doubt both of them would go bad at the same time.

 

If that doesn't isolate the issue now you are down to some expensive repairs for which you would be better off buying a new PC. You can always install your new video card in a new PC as long as it has a PCIe x16 slot.

 

Paul

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scoobdoop
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Message 6 of 11 (4,339 Views)

Re: HP Pavilion a6600f desktop PC not communicating with monitor

I am having the same problem with a Pavilion a6600f I am working on for a friend. I have also tried adding a video card to no avail. A monitor I am currently using was tried and also did not recieve any signal. RAM was tested and found to be ok. Just had this happen on a much older pavilion about a month ago and it was the motherboard.

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erico
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Member Since: ‎01-07-2009
Message 7 of 11 (4,335 Views)

Re: HP Pavilion a6600f desktop PC not communicating with monitor

HI,

Welcome to the HP forum!

 

Try removing the memory modules and putting one module in the sot closest to the CPU. Now try powering up your PC.

Try one memory module first and if no success try the other in the same position.

 

If no joy with the memory module test I recommend that you clear the CMOS (BIOS). 

 

regards,

erico





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2014 Microsoft MVP - Microsoft Windows Expert - Consumer

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Message 8 of 11 (4,326 Views)

Re: HP Pavilion a6600f desktop PC not communicating with monitor

I discovered the solution after I realized the booting sequence was not even initializing.  A simple online search for "black screen" and "no boot" led to multiple results addressing problems related to the integrated NVIDIA gpu chip.

 

The chip is apparently prone to overheating to the point where its connective solder can melt and break its link with the motherboard.  This issue predominantly happens in laptops due to the tight enclosure, but has been reported to also occur in desktop models such as ours.

 

This broken linkage results in a black screen and an inability to boot into BIOS.  Many of these instances have been misdiagnosed as "failed" motherboards.  Fortunately, there is a fix called "reflowing."   This amounts to reheating the gpu chip to the point where its solder reflows to reconnect its detached pins.

 

Some repair shops are fully aware of this problem, and offer to fix it for around $80 at present.  Some do-it-yourself laptop owners have also posted online videos to document how they have reflowed their own chips using a variety of means.

 

I decided to take the latter route, reheating our NVIDIA gpu chip with a heat gun using a heat shield to protect the surrounding motherboard components.  My reflow attempt worked just fine, so I reattached the gpu's heat sinks with some fresh thermal compound to finish the job.

 

To recap the issue, our HP Pavilion a6600f desktop PC lost communication with its integrated NVIDIA Geforce 7100 gpu chip due to the chip overheating and melting its connective solder.  This broken link compromised the motherboard's ability to initialize its boot sequence, giving no output to the monitor, resulting in a blank screen.  A new graphics card did not solve the issue since the motherboard was inoperative due to the connective problem with the integrated gpu chip.  Reflowing the gpu chip solved the problem.

 

PROBLEM SOLVED!

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rkmats
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Member Since: ‎03-01-2012
Message 9 of 11 (4,034 Views)

Re: HP Pavilion a6600f desktop PC not communicating with monitor

Reheating the Video chip worked for me....Thanks sooooo much for the tip, the only thing I have to add is the location of the chip is next the processor and on the heat sink "FOXCOMM"  is written.  I used a butane torch that shot a small blue flame....Bottom line is ITS WORKING.

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ColorGuru
Posts: 5
Member Since: ‎01-11-2013
Message 10 of 11 (2,788 Views)

Re: HP Pavilion a6600f desktop PC not communicating with monitor

I am having the same symptoms so I may have the same problem. 

Can you tell me more about how you re-melted the solder?

I assume that you removed the motherboard and re-melted the solder on the back of the motherboard where the GPU is attached. Is that correct?

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