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02-01-2012 07:12 AM
I have a dv7-3160us laptop that appears to be having thermal issues.
The fan seems to run at hign speed during the bios startup then goes down to low idle and does not increase speed when the CPU temps climp up (54 according to SpeedFan)
bios is set to always on bios version F12 (updated to F13 then back)
Problems started when I left the laptop in the truck overnight (7 degrees F). When I got in to the office, I let it warm up for 15 min or so the tried to start up. The power button would light up then go out. Waited anther 15min and it started up. Few hours later while running mutiple applications as normal (AutoCad2010, Media Player, Excel ect) the system crashed and froze up. I let it sit as it was for 5 min or so then forced shutdown by holding the power button. This is the first time it's happened. When I tried to restart, I had the same issue as the morning- push power button, tries to start and clicks off before bios was done. I did blow a large amount of dust out when it first shut down as I usually do every couple of weeks. I stripped the machine bare last night and pulled another hunk of lint out of the fan, but the internals were only mildly dusty.
I now have the laptop propped up with 2 large muffin fans blowing in the back and the CPU temps hover around 45 at idle, 54 when running even media player. I've never monitored the temps before, so I don't know if this is normal or not. If I shut down, I have to let it cool for 10 min or so before it will re-start.
Bottom line, is the fan toast (replace?) or is the control portion of the motherboard dead (i.e. buy a new laptop). I think I found the fan part number 533735-001, and it appears to run in the $50-$75 range, but I'd love an edjucated optionin if this will solve the issue.
I'm an electrical engineer and this is my main computer. I can swap hardware with the best, but am not current on any software/bios fixes aside from updates/checking bios settings.
02-07-2012 01:09 PM
-First off, the statement that you "blew a large amount of dust" out, as is your usual periodic practice, sets off alarm bells. Any laptop or notebook does not normally collect "large amounts" of dust in it's cooling fins, and, it would take long periods of time (months) for significant dust to collect in normal use. That said, having pets in one's household (or vehicle) will indeed cause problems, with their relatively large fibers easily leading to blockage of air-flow at the fins and collection of larger amounts of dust. Do you have pets?
-Second, your post did not indicate if you had left your computer "running" while in your truck. Your inclusion of a
7 degrees Fahrenheit temperature number implies that you did leave it running (else why would it be relevant?).
-Now for some useful information: most common cause of problems with CPU cooling in Laptops/Notebooks is
just ONE single instance of blocking the incoming air-flow vent (or less-commonly, blocking the outflow vents).
Blocking of incoming air-flow is unfortunately waaay too-easy to do, due to the location of incoming air-flow vents on the bottom of such devices.
-Just ONE single instance of blockage will cause OVERheating of all components near the CPU die, AND near the heat-pipe, AND near the fins. The CPU may run 'fine' (i.e.- without noticeable problems) for some length of time, and may-or-may not reach the critical "Shutdown" temperature programmed into your specific device's firmware.
-Common results include: melted insulation of the fan wires (often difficult to notice because of common use of a thin 'heat-shrink' over some of their length as a means of 'bundling them'); a dried-out / failed CPU-to-heat-sink-surface 'bond' (where the OEM's special silver-bearing heat-transfer compound is located); CPU / heat-sink temperature sensor damaged, giving incorrect data such that the system can no longer function correctly; and many similar over-heating related problems...to repeat, "from just ONE blockage event".
-Personal experience: a circa 2010 HP laptop was booting up with "cooling fan not" working error message, and a warning that system will shutdown in 15 seconds. Took the laptop apart all the way down to the CPU
cooling fan, removed it, pulled off the plastic squirrel-cage-style fan WITH the plastic 'cup' containing motor's
PermanentMagnet, looked over the inside-out-design's copper windings, and they looked perfectly OK. Said
"hmmm" to myself, then looked up a New part on the www: $14 for this laptop; not tooo bad. Then, decided to
actually apply some DC voltage to the motor for testing. Good thing; when i cut into the black heat-shrink 'wrap'
i found melted insulation; the red +5VDC and black Ground wired had shorted. [Lucky for me, that some EE
somewhere designed the circuitry of this Laptop's motherboard correctly, with a 'crowbar' circuit that shut off
power to the shorted fan. Your specific motherboard's fan-power circuit may be fried permanently.] Long story
short-er, i cut out the damaged wire lengths, soldered in some 30gauge stranded replacement lengths (having proper American-made heat-rated insulation) with appropriate joint heat-shrink wrap...and the little
fan worked just fine when everything was re-assembled. (I did apply 4.5VDC from 3 D-Cells to it just after it's repairing, and it spun up immediately.) **Note: soldering such tiny-gauge wires is recommended ONLY for
experienced component-level techs with very steady hands; if you are not one such, buy a new Fan!
-One should be aware that a 3rd wire (often yellow) is normally present to provide Fan-RPM data. If that signal has been impacted by over-heat or other damage, the computer will also not function correctly.
02-07-2012 02:18 PM
I should have given a bit more detail on the background-
-Dust: I'm an electrical engineer in a manufacturing facility. My office is technically "on the floor" and subject to the dust created. It's a very fine dust composed of wood, Fiberglas, and dirt mostly. No fibers. I don't own pets, and it doesn't clog airflow, just coats the heatsinks/internals lightly (impeding their thermal transfer) The dusty environment is a fact of life for me, just have to be more dilligent on the cleanouts.
-Computer was not running or hibernating in vehicle. It was in a fully shut down state. Computers have critical operating temperatures both high and low. 7 degrees F is well below typical HDD operational thresholds (HItachi HDD in my Jeep won't boot under 15 or so- no tunes til it warms up).
I think what happened is transfering from the cold vehicle to the warmer office, condensation formed on the motherboard and I didn't give enough time to warm up and evaporate would normally happen. The fan operated properly during bios startup, I believe the motherboard that controls speed was the portion that was damaged. I did replace all thermal transfer compounds/pads with no positive result.
Unfortunately, the computer is now totally dead after struggling along for the past week. I will be repairing for media use at home (new motherboard) and buying a new Dell XPS for work usage. I will post an update if in fact the motherboard takes care of the issue. I found the fan to be fully functional both in speed variations with my desktop PWM power supply and scoping the yellow "tach" signal.
Thanks for the input sir, but the damage was already done... next time I'll tell the sleeping kids to wake up and walk so I can grab my laptop case!