Acer Aspire TC-780 CPU Fan will not spin

Hello, I have purchased an Acer Aspire TC-780 a few years ago. I have been using it as a home server for the last few months. Recently, I've noticed that the CPU Fan does not spin. Ssince I run it with the cover off, I thought little of it. I thought that because I run it with the cover off, the CPU was just getting enough airflow that the CPU Fan does not need to spin. Howerver, now I have noticed that even under load, the fan will never spin. Even on initial power on, the fan does not spin. I have checked the BIOS, and it says the the CPU Fan Speed is "N/A". I have tried reseating the 4-pin power connector, but this did not help. Does anyone know a way to fix this? This machine is crucial to my home network setup, and it really sucks being without it, but I don't want to risk it overheating due to the broken CPU fan.

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StevenGen

https://community.acer.com/en/discussion/684089/acer-aspire-tc-780-cpu-fan-will-not-spin

Test the fan if it works first, put the cpu fan plug into the other fan plug #4 (see caption below) as it could be that the fan is faulty or the mobo plug is faulty and you need to either change to the other fan plug on the mobo or buy another CPU fan or get a completely different cpu cooler..

Techflash

I can confirm that the #4 connector works, as I have a case fan plugged into it. I will check if the CPU fan works in there after I get home from school.

Larryodie

Speccy is a good utility to monitor your fan tempature etc while in operation.

BUT your bios shold have an enable or disable smart fan.

LOOK in your bios to see if it is ENABLED.

Larryodie

Here is my bios from TC-899-UA92 with Smart Fan and temp.

I can only see this in stand-by.

Speccy will show your temp and fan status while in operation.'

I'm not sure as to the temparture needed to staart the fan ??? Maybe someone else knows?

fanbios.jpg

billsey

I don't know on the TC-780 specifically, but typically the BIOS spins the fan up as part of POST, before setting the speed based on CPU temperature. My guess is the fan has failed, and that's an easy fix.

Techflash

Just tried swapping the cables as per @StevenGen's suggestion. Nope, presumably the fan is just dead, still doesn't spin up. Will try some more tests though. @Larryodie, you mentioned using Speccy for checking the fans. I currently have an Arch Linux install on the system, so I can't easily test with Windows based tools. I can however give a little more info, such as the specific message I was talking about in the BIOS. As you can see in the image, the CPU temperature isn't particularly warm, but it's a little toasty for essentially idle. By 52C I would imagine that it should probably at least spin up the fan a little.
By the time that I finished typing this message it went from 40C to 57C and rising, doing nothing but watching the BIOS menu, CPU fan still not spinning and still says N/A like in the pic. I'm going to shut it back down because that's really hot for idle, and it's still not spinning.

StevenGen

https://community.acer.com/en/discussion/comment/1197369#Comment_1197369

The cpu temps that you are getting is not very hot at even 57c temps, it might be that the TC-780s fan only comes on at higher temps like 65c plus, get a hair dryer and ts=est it out if the fans come on? But the simplest way to test the cpu fan mobo plug #3 and #4 is with a multimeter, put the multimeter RED prong on the RED or YELLOW 12v+ and the BLACK - Ground pin (see diagram) and see if there is any voltage coming out, as if there is a 12v voltage coming out then your fan is faulty and you need to replace it, if you don't have a multimeter then use something else that you can measure a 12v otput voltage.

The best is to get a new LGA1151 cpu cooler and fan like the Cooler Master Hyper H411R Compact, as this cooler is only USD $29,00 and will give you much better and superior cpu cooling to the oem one.

Larryodie

SteveGen

He will need a CONTOL voltage as well as the 12VDC.

Commodore_1995#

I would check the bios version later:

Techflash

I do not have a multimeter, nor anything else that I can measure power with (unless there's something super common that I could use)
I also have updated the BIOS to RO2-B2 like a year ago.

Larryodie

A cheap $10 digital multi-meter is a Must Have.

Don't be scared by the cheapness as long as you don't drop it otherwise the accuaty is outstanding on all that I've owned as good as my exspensive Flute's but not as rugged.

You can use a car/truck's tail lights etc as a tester in a pinch but meter's are cheap.

Techflash

I will gladly grab a multimeter, but if the question is if those 4-pin ports work, the answer is yes. The system's case fan works in both. Is there anything else that can be done to test it?

Larryodie

Possibly try to spin it manually and/or suirt a drop of oil in it (if possible)

Most motors have bearing seizures. DONOT get oil on anything else. JUST a drop of light oil on a toothpick.

Personally I would replace it and the cooler as Mr. Billsey says unless you check the voltages to ascertain if you have the 12V and the Control voltage.

You should be able to ohmmeter the motor to continuity check the coil.

Techflash

Alright, well my father says that since we don't have a multimeter, we're gonna shop around an find a good one to keep for a while, so that's out of the question for at least a week to find one, plus however long it takes to ship. For the oil trick, I assume that would involve disassembling the fan? So not something I can do in the 5 minutes before school starts. I'll try that out once I get home. I would gladly replace the cooler if it turns out that this one is simply dead, that's not really a problem.

Larryodie

You really need to be surethat the fan is BAD before you disassemble or oil.

Youtube has video's on cleaning and oiling fans.

Multimeters are sold at local parts and local hardware stores. Harbor Freight usually has $10 units that I've used. I keep them in my car and trucks for checking fuses, batteries etc

Techflash

I mentioned one from harbor freight to my father, but he said he wanted a higher quality one if it's one that we're going to keep for a while, and he won't let me change his mind.

Techflash

Ok, my father got a mutlimeter. @Larryodie you said to check for continuity on the motor and coil, right? I've never really done stuff with either fans or multimeters before, so a few questions:
- I assume I need to take off the fan to access those? If so, does it need to be plugged in to the mobo for it to work?
- Is there any specific setting I would need to use on the meter? Is it that "ohmmeter" that you mentioned?

Larryodie

Forget the ohmmeter continuity checking as I not sure if it would show on this motor BUT check Pins 2 and 4 for voltage as in SteveGens post.

acerfan.png

Larryodie

Edited to show pins 2 & 4 should have voltage.

Pin 4 will only have voltage when it is HOT enough.

Pin 2 should have 12V ALWAYS with power on

I'm not sure as what tempature will turn it on ??

Use pin 1 as a ground, The black wire of your meter.

DO NOT use your meter on OHMS when checking any voltage. USE ON DC volts ONLY .

Use a common battery to check your meter and settings, Most 1.5 volt batteries will read 1.65 VOLTS when new.

Be careful

Techflash

I've already tested my meter on various things, I heard the most common way to check is to simply plug it into an outlet, red in the small slot, black in either the 3rd prong or the long one, both showed 120-ish volts AC. I also tested it with DC on a random PSU I had lying around, the PCI-E connector showed 12V DC. So I know the meter works. Also I'm not sure that either of the pinouts you sent is correct. Looking at the Intel cable, it goes in order from left to right: Yellow, Blue, Red, Black. I assume it should still be simple to test? Red goes in the yellow pin, (12VDC if I'm correct), and black goes in black for ground. Not going to try it until I know for sure though.

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