Corsair H60 cooler cycles on and off every 3-4 seconds

[hfffoman]

I just installed a new motherboard and the CPU fan isn't working. Consequently it won't boot. A bit of detective work is needed here. If I explain the exact situation there are enough clues for someone smart to figure it out.

The old board was professionally installed and instead of plugging the CPU fan connector onto the motherboard they plugged the two power wires directly into a power cable from the PSU. That leaves a single wire in the connector which goes into the IN pin when the connector is correctly located on the motherboard. This arrangement always worked fine and I think it's recommended by Corsair. The new motherboard is similar to the old but slightly upgraded (ASUS Z97-P instead of ASUS P8Z68V-LX). It has exactly the same fan socket configuration.

When I first turned on the motherboard the fan didn't work at all. The machine started to boot. Of course the CPU temperature started to rise and I quickly turned it off before it went above 34C.

I found that one of the CPU fan power leads was loose. I then made sure it had a good contact and next time the fan worked. But it cycled on and off every 3-4 seconds and the computer wouldn't boot. When I pressed the manual override on the fan it still turned off after a few seconds.

I then unplugged the connector with the single wire from the motherboard. The behaviour of the machine was exactly as before - the fans runs on and off every few seconds and it won't boot. This suggests the signal isn't getting through from the motherboard to the cooler.

I then got hold of a cheap fan with a conventional connector and plugged this into the motherboard. The fan works as normal and the machine starts to boot. Again I quickly switched it off because the working fan wasn't attached to the CPU.

So it looks like one of several possibilities:

1. The new motherboard won't tolerate the unconventional connectors. I would be surprised if this were the case given the similarity of the boards.

2. The wire is broken. I can't see any sign of damage but it probably got pulled a bit in the course of changing the motherboard.

3. The cooler is bust. However, the last time the cooler was switched on, with the old board, it worked fine.

What's your advice?

 

[Paperdoc]

OK, this is a new thing to check I have not mentioned earlier. I presume from your last post that, in saying " I rebuilt the computer and...", you mean you re-assembled it in the case, not on the external "breadboard" surface.

A case comes with a backing plate that has many holes in it threaded to accept stand-offs. Especially when you have used the case before for a system, there will be stand-offs screwed into some of those holes, but not all. The extra holes are to allow for adapting to different mobo layouts.

The stand-offs provide two functions. First, they provide mechanical support and a fixed location for the mobo. Secondly, the mobo is designed to be grounded to the case back plate by the stand-offs, but at NO other spots. For this the stand-offs normally are metal (often brass, about ¼" long, with a threaded hole in the top and a threaded shaft out the bottom), and the mounting holes (often 9 in 3 rows of 3) all have little metal "fingers" in a flower petal pattern around them.

There are two rules for where the stand-offs are screwed into the back plate holes. First, ideally tou want one under every mobo mounting hole so it is fully supported. But MOST importantly, there should NEVER be a stand-off under the mobo where there is NO mobo mounting hole. Having a stand-off in the wrong location can short out a trace on the mobo bottom to ground. So, inspect your case and mobo carefully to verify that the stand-offs are all correctly positioned. You MIGHT have to remove the mobo from the case to do this.

Just an additional note. On a few cases I've seen, one odd stand-off is included. It has an insulating rubber top on it, rather than the threaded hole. This one is intended to place in a spot under the mobo with no mounting holes, but where you perceive a need for mechanical support.

 

[hfffoman]

Yes, I had reassembled the machine in the case. I took it out again and there were no extra stand-offs. It was now working well with memory in slots 3 & 4 but wouldn't start with memory in either 1 or 2. I also noticed that with these slots empty it would now boot into Windows and didn't crash for a few hours, so maybe the crashing was caused by the mobo rather than the old Windows installation. I have just returned the mobo. My concern now is that the shop is going to conclude that it's the pins and blame me as they say they tested it before sending it out. It is quite possible that I have damaged the pins with all the fiddling around I have done but I am pretty sure I didn't cause the initial problem. I only placed the CPU in carefully the first time and it didn't work.

 

[Paperdoc]

Here's hoping the replacement mobo will work well. Let us know.

 

[hfffoman]

I returned the motherboard. They tested it and found it to be fine. I sent them my CPU and memory and they found one of my RAM modules was faulty. They returned it to me and it now works with just the three good RAM modules installed. However, they said they had tweaked the pins and I suspect that was the real problem as I was getting failures with all of my RAM modules individually and I wasn't getting failures if I put them in different slots. So it seems to be a combination of the pins, the memory and the fact that sometimes (not all the time) I was testing with the screen attached to the mobo unaware that the CPU doesn't support onboard graphics.

There is one other lesson that comes out of this. The reason I bought this motherboard is that my old one suffered bent pins when I upgraded the CPU. So I have got damaged pins twice in short succession. Now, I am sure I was not doing anything dumb with the seating of the CPU. It is obvious how to slip it into place in the right configuration. However, it is possible that the cooler was putting some incorrect forces on the CPU. The cooler was attached with 4 screws one in each end of a springy X-frame. The screws rested in slots so there was a lot of freedom in the way the cooler pulled onto the CPU. It could easily have had latitudinal forces or uneven forces. The mobo supplier suggested this may have been the problem.

For good measure I also replaced the cooler and got a Coolermaster hyper 212 which works fine, is much quieter than the old H60, and has 4 pins so there is no need for complicated connections.

Thanks again for your help

 

[Paperdoc]

You're welcome. Glad to hear you got things cleared up!