I am having a couple of problems with the A8N-VM CSM motherboard.
I have 2 of these running in different machines with different components. With the first problem, I am having it in both machines.
1) When I try a "cold boot" on either of my PC's, the power comes on, lights light up, fans turn, etc, but the computer will not post... no beep codes, nothing... just sits there powered on with a black screen. However, if once it is turned on, I hit the power switch to turn it off and then turn it back on really fast, it will post and boot up and run fine. Been scratching my head about this for months now with no answer.
2) My second machine mysteriously powers itself off completely when no-one is around. I have checked the power saving features as well as all the program updates that might be running and telling it to reboot, but keep comming up empty handed.
My first PC should be in my Sig. the second PC is as follows (the best I can remember):
AMD Athlon 64 3400+
ASUS A8N-VM CSM Socket 939
2 x 512meg PC3200 DDR Crucial Ram
ATI Radeon X1600XT 256mb PCI-E Video Card
250gig Maxtor SATA2 Hard Drive
ENERMAX Noisetaker 420w Power Supply
I have worked in the field as an IT Tech for over 20 years now, and these problems have me stumped.
These are beautiful motherboards when they are right. I bought one for a household computer (still one of our favorites for its responsiveness). Just plain works, and has nVidia's good built-in graphics (6150-430) which they are now trying to get more money for or limiting production of IMO. Before I bought it, though, I did a lot of research on it (since I liked the specs, but it was causing a lot of grief and RMA's for people at the time).
From what I could gather and put 2 and 2 together, the northbridge heatsink was rocking on the NB chip (which is small - there's not much surface for the heatsink to sit on), which was causing heat-related issues, and sometimes was even sawing and damaging the corner of the chip from its poor seating, which of course would make the board useless.
Problem 2 was that there was no heatsink at all supplied for the SB, and people were complaining about its temp. Luckily there are 2 holes there so you can do something about it with the help of Zalman's NB heatsinks, which I did.
As far as the NB problem, I took off the heatsink and cleaned off the thermal grease in this instance, and after proper cleaning put Shin-etsu compound on the factory heatsink. This is a ceramic type grey colored paste that somewhat adheres and eventually hardens that it holds the NB factory heatsink in place enough in both states under all conditions.
Summing up, check for damage or poor heatsink contact.
The Chipset heatsinks (or lack thereof) was the first thing I noticed about this board when I first bought it, and immediately replaced both north and south bridge chipsets with Thermaltake CL-C0034 heatsink/fans and fresh AS5.