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08-04-2010 09:08 PM
New motherboard fixed my problem. M2n78-LA. I bought one off ebay, it was not the exact mobo that came out of the PC, but it was close enough that Vista recognized everything and everything worked. The problem is the NVIDIA chip. I was able to get mine to work for a little while with a fan on the heatsink, but it would eventually still go stupid. I am going to experiment with a larger heatsink, and a fan, and see if that will work. I am not going to try heat sink grease, I am going to glue the heatsink to the top of the chip with JB weld. What can it hurt, the board doesn't work now anyway.
The board I bought was a Pegatron, it came from china. When I loaded the defaults everything was in French, so that must be where it came from. I can post the results of my experiment if you want.
08-05-2010 05:16 AM
Thanks for the info. Keep me updated if your experiment works.
I bought a pci express sata card yesterday and still had problems. When I boot linux off of a usb drive it detects the cd drive and the hard drive now, but will not boot off of the new card. I think I'm just going to replace the case and get a different motherboard and just reuse the chip and memory. I'm sure this will just happen again with a replacement. Of course this all happens 3 months out of warranty.
08-05-2010 02:34 PM
I am having the exact same issues with an HP model P6157c desktop Motherboard M2N78-LA. I've done everything already mentioned (with exception of replacing the motherboard). I have replaced the processor .... no help. If my PC sits powered down for at least 4 hours, then it boots up to where I can get into the Bios settings, but only on rare occasions will it go past that to the Windows startup screen. After the 1st attempt, then a reboot, I will get the "reboot & select proper boot devices" message, and I'm doomed until it sits with no power for a few hours .... indicating a heat issue somewhere. Circuit coolant sprayed here and there has no effect. I have noticed that once it is in the "reboot & select proper drive" message scenario, as soon as I push the power button, it immediately powers down, instead of waiting 5 seconds or so while holding down the power button. Does this mean anything to anyone? I'm about ready to just trash it and get a new one. It just went out of its 1 year warranty. GRRRR
08-05-2010 07:38 PM
Everything runs through that NVIDIA chip. SATA, the onboard video, everything. With mine, if I let it warm up and let it get to the point where it ignored the drives, and then re-booted, I couldn't even get video. Just plugging a SATA card in will not work, because the NVIDA chip controls the slot the SATA card plugs into!
I ordered more RAM and a new CPU heat sink and fan, as soon as I get it back together and JB weld a big heatsink and fan to the NVIDIA, will let you know what happens.
08-06-2010 10:30 AM
Using JB Weld to glue down the heatsink on the chipset (Northbridge) is not a very good idea. I don't know what the thermal transfer properties of JB Weld are but they more than likely are NOT very good (for all I know maybe no better than concrete, not to mention all the microscopic air bubbles in the glue), and certainly not even close to being as good as a heatsink paste specifically formulated for that function like Artic Silver 5 or others. In fact, the heatsink would probably dissipate heat better with nothing at all on it than with using glue. You will probably do more harm that good and cause the chip to run even hotter which is exactly the opposite of what you are trying to do.
You would be much better off getting a chip cooler and using heatsink paste. Also I would look into using a CPU cooler like the Cooler Master GeminII S that blows plenty of air down over the motherboard and not only cools the processor but also the regulators and chipset.
08-06-2010 11:41 AM
i'm done messing around. i'm ordering a different motherboard from newegg that should fit the oem hp tower. i was able to return the pci express sata card (which cost the same as the motherboard anyways) and i don't want to take any chances with another m2n78-la
I'm going to try this motherboard out. it's a gigabyte GA-MA785GM-US2H
Hope it fits in the case nicely.
08-06-2010 01:59 PM
The motherboard should fit. You might look over the mobo 8 pin power plug verses your 4 pin and also all of the mini-tower connectors.
08-12-2010 04:55 AM
I have decided to abandon the m2n78 in favor of another board that doesn't use the NVIDIA chip. Ordered a used board from China, it had issues too so its getting sent back. I tried arctic 5 and a chip cooler fan, it extended the operation but it still eventually fails. JB weld will not work (as a previous post had said) because of its thermal transfer properties.
Interesting note is the board is discolored around the NVIDIA chip on my original board (backside). This would indicate to me that an overheat occured. Maybe HP engineering misjudged the amount of heat generated by the chip and instead of using a chip fan, just used a passive heat sink.
Whatever the root cause, I am done sinking money and time into this particular HP PC.
08-29-2010 06:48 PM
This has happened to my m8530f also. I have replaced power supply with a new one, Hard drive with a new one. hard resetting the bios,nothing will correct it. I think something is going on here to have everyone having the same issue at the same time.