Please help! ASUS Motherboard DIMM slots not working for me, but work elsewhere.

Danman77

Commendable
Apr 7, 2016
13
0
1,510
Greetings everyone,
So I'm completely stumped. I'm sorry if this is long winded, but I want to give as much detail as possible because I don't know what information may be pertinent.

I bought a used Asus P8z77-V motherboard. The seller claimed this is 100% working. I have installed this same mobo into many builds, so I know it fairly well. I have been building PC's for many years, so I don't think I'm missing anything simple (like incorrectly seating the RAM).

I installed the mobo into a new CoolerMaster HAF x case. Placed the 3770k CPU in. And then installed a brand new, but tested, CoolerMaster Nepton 240m CPU cooler. I installed 4 sticks of 4GB G.Skill RAM (tested in same model mobo and worked), but the motherboard wouldn't even POST and the red LED for MEM error was lit. After pulling all the RAM and placing on module in at a time I came to the conclusion that DIMM slots A1 and A2 were bad. Anytime a RAM module was installed in either of these slots, the board wouldn't POST. Just for troubleshooting purposes, I swapped CPU's, tried completely different RAM modules out, and cleared the CMOS, but still came to the same results.

I sent the motherboard back to the original seller. Today he emailed me stating that the board is working fine for him. He's tested all 4 DIMM slots and he's not getting any errors. He is still offering a full refund, so I have no reason not to believe him (in fact he's been great with communications and tried to help with troubleshooting while I had the board).

I'm so stumped. Does anyone have any idea as to what could cause this? How could a mobo not work for me, but work for someone else?
 
Solution
It could have been shorting to a post or the I/O backplate. The seller most likely tested it outside of a case as I always do. That way if it no longer works properly once in the case I know what to check.

Danman77

Commendable
Apr 7, 2016
13
0
1,510


No, I only tried it inside of the case. Can a case actually effect the motherboard like that? If so, how and what should I check for?
 

Danman77

Commendable
Apr 7, 2016
13
0
1,510


Well now, you've given me something new to think about. I have never tested a board outside of a case because I was just assuming the case is a shell. How do you test it without a case, do you just place the mobo close enough to the case to use the power on/off and reset cables? Or is there a special tool you can use to replicate that?

 
I don't need a case to test a motherboard. All I need is a PSU, keyboard, mouse, etc. An old motherboard jumper makes a great switch; but anything that can short 2 pins like a screwdriver, a dime, a paperclip, etc. is fine. I always test like that and if it all works fine, then it goes into a case.
 

Danman77

Commendable
Apr 7, 2016
13
0
1,510


Wow, great idea. I love it when I learn new troubleshooting techniques. After building computers for customers for many years, I considered myself a pro. Computer building sure has a way of humbling you sometimes.

That being said, I took a close look at the empty case and did notice that two of the mounting screws were slightly different from the rest. They were about 1/4 mm higher than the others. How they got mixed in with the other screws, I'll never know. Do you think the slightest bit of torque being placed in the center-top and center-mid of the mobo could cause this whole issue?