Laptop fan power problem

JoeBDK

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Jun 20, 2013
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Hi guys, I'm having an issue with my laptop's fan. I'm on an HP DV7-6100. A while back, I began receiving the 90B error message that says the fan isn't working properly. At first it was intermittent, sometimes I got the error message and sometimes I didn't. Then it became constant, so I disassembled the laptop and made sure all the vents were clear of dust, however I still received the error message. I assumed it was the fan, so I ordered a replacement fan. However, I removed the fan and jury-rigged some AAA batteries together to test the motor on it, and the motor is working fine. As a temporary fix I've got the fan running constantly on an external power supply, but the system it still hitting high heat levels of around 92C when I'm playing a game like Civilization.

Basically I'm thinking there could be 2 issues: either the 4-pin connector on the fan is faulty (in which case a new fan will solve the issue) or the motherboard's connector either isn't sending enough power or is having some other issue communicating with the fan. I'm comfortable poking around inside my laptop, but I'm afraid checking voltage on a running open laptop motherboard or soldering things is a bit out of my league. I'd rather not give up on the laptop since otherwise it's a great machine, but I'd also prefer not to try to replace the motherboard. Is there anything else you guys think I might be able to do to deliver the correct power to the fan or figure out where the problem might be?

Thanks,
Joe

UPDATE: See below, I thought I resolved the issue, but now the whole system won't turn on.
 

kellmike626

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May 6, 2013
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Regarding your temps...maybe try replacing the thermal compound on your CPU and heatsink, as well as GPU. Give it a good cleaning with some isopropyl alcohol, use a quality Thermal compound (I used Arctic Silver 5 on my HP Envy when I took it apart to re-paste it). That'll probably reduce your temps by quite a bit and make your DV7 quieter, since the thermal compound that comes from the factory is garbage.

Since you clearly have the skills to disassemble the laptop, that shouldn't be too difficult for you.

If you have the new fan handy, I would just swap them out and see if it solves your error when at boot. I've heard of the 90B error on some HP G series laptops, but not quite familiar with them (I haven't worked on a lot of HP computers), excepting that knowing that it usually points to the fan inside the computer failing.
 

JoeBDK

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Jun 20, 2013
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I did as you said, replaced the fan and thermal compound on the GPU and CPU. There was also some thermal tape on the capacitors etc but I didn't have any handy so I left the thermal tape alone. Powered it back up and things seemed to work good as new, no fan error, no overheating. Things went great for a few days without issue, Last night I was working on my design portfolio and shut it down for the night, no problem.

This morning, however, I went to turn it on and got nothing. Checked the AC light and it was on, so that wasn't the issue. Did a hard reset, detached all the peripherals, battery, and power cord and held down the power button for 30 seconds to see if that was the issue, but it's still not turning on.

So did I just fry my motherboard? Or does this sound like a new, unrelated issue?
 
If I understand correctly: the fan was not spinning when connected to the board, so you powered it externally and ran the computer, and temps reached over 90 C?

Seeing your second post now leads me to believe that your ICH/PCH chip may have gone bad.
 

JoeBDK

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Jun 20, 2013
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Pretty much. Once I was able to power it externally, temps became a little more manageable but still excessive. Installing a new fan and redoing the thermal paste on the GPU and CPU seemed to fix things, but tthat didn't last,

If it is the ICH/PCH chip, why would it have started working again when I replaced the fan and stop giving the error message? And would thaat mean that I'll need a new motherboard? If that's the case, I think I'll just cut my losses and build a desktop system to replace it.

Thanks for your help.
 
Well, the fact that the fan wasn't being powered by the board as it should implies there is already something wrong with it, whether it's the fan controller, or perhaps the PCB. It's possible though, that the temps were not recorded or relayed accurately since the fan was not physically connected to the board - therefore, the ICH/PCH chip may have misrepresented the actual temps.

It's a little difficult to diagnose, but in any case, you may or may not need to replace the board. A desktop might end up being better for you, if you do have to cut your losses.
 

JoeBDK

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Jun 20, 2013
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The original fan wasn't being powered by the board, but a replacement fan seemed to do just fine. At this point I have given up on it. I just bought my wife an Asus n56dp-dh11 to replace her old laptop, so I'll be using hers to figure out my new system. Perhaps in a few months I'll get around to ordering a replacement motherboard just to see if it works. Thanks for your help.
 

killac93

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Oct 7, 2014
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Hi JoeBDK, I'm having the same exact issue and was wondering if you ever got your issue resolved. I have replace the fan and the motherboard. Also updated the bios. Still getting the same fan error message. Thanks.