Can't get Z87 UD5H through POST with more than 1 RAM module installed

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26 Jan 2014
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Hi,

I am running an i5 4670K in a Z87 UD5H with 8GB of Corsair Vengeance DDR3 1600Mhz RAM. The system was running perfectly up until yesterday when I decided to do some work on the computer that required the removal of the Seidon 120M water-cooler and removal of the motherboard. During this procedure I did not disturb the CPU itself but did remove the RAM and disconnect most of the additional pieces of hardware such as the Graphics Card (MSI 760 Twin Frozr).

After putting everything back together the computer would not boot and I was getting an error code 15 on the motherboard. I checked everything was seated correctly but could not get it through the POST. I tried disconnecting all non-essential hardware and ran the system with a single RAM module in slot 3_1. The system booted perfectly. I started to add more hardware and ultimately was able to conclude that the system will only boot up with a single RAM module in slot 3_1.

If I swap the RAM modules the system still boots okay, but only if the RAM is seated in slot 3_1. If I try moving to any other slot, or any combination of RAM modules other than just 1, the error code 15 is displayed on startup and the system will not boot.

I have flashed the BIOS to the latest stable release (F7), tried the alternate BIOS, reset the CMOS, I also tried removing the motherboard and running it outside the case. Nothing seems to fix the problem. I also tried removing the water cooling system, thinking the frame on the underside might be shorting something, but there was no change.

The only thing I have not yet tried is checking under the CPU for bent pins, but can't think why they would be bent having not removed the CPU during the procedure.

Does anyone else have any good ideas for what I might try?

Thanks!
 
Try loosening the CPU heatsink/cooler mounts,could also try loosening the mb mounting screws slightly

Overtightened CPU cooler and motherboard flexing can cause memory issues
 
Thanks for the quick reply. I did try the system without the water cooler block fitted at all, and still got the error code 15 on startup though.
 
I wouldn't try it without a cooler,could test withthe stock Intel cooler if need be

I doubt its bent pins if the CPU hasn't been removed,have you tried loosening the mb mounting screws? If the mb has flexed or bent slightly when moving it might cause memory slot troubles
 
Thanks,

I tried without the cooler and the problem is still there. I decided to go ahead anyway and look under the CPU and found a couple of bent pins! I was able to straighten them out with a watch makers loupe and some very fine tweezers before reseating the processor.

Having put the lot back together again the problem is still there but now manifests slightly differently in that the computer fails start with code 15 and then restarts itself.

I might try zapping the cmos again and trying the alternate BIOS....
 
I didn't think any would be bent considering the CPU wasn't removed

If its still throwing that error I'd double/triplecheck the pins,post pics up of the socket/pins if need be,if any are even slightly out of alignment you'll see issues

The integrated memory controller is inside the CPU so bent pins = memory problems
 
Ok, I was stupid and didn't seat one of the RAM modules correctly when I put it back together after straightening the pins. Its now booting fine and showing all 8Gb of RAM. I'm truly puzzled how the pins got bent in the first place though! This is the first system I have built with LGA1150, and I did find the initial CPU installation a little tricky, maybe I bent the pins then but it was only after a small amount of movement in the chip position whilst removing the cooler that caused the problem many months later?

Thanks for your help, its always nice to have someone to bounce ideas off.

The whole point of my work yesterday was to remove the blue LED in the water cooler and replace it with a red one so the system looked better! Would have been a shame to nuke the motherboard and processor over a small light!!
 
Yh it could have took time to surface,its usually when you disturb components that issues crop up,atleast you managed to fix it,it should be fine now

Pays not to mess with the pins too much as they fatigue and can snap off without warning
 
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