Should I RMA this A7NX DLX 2.0 board?

I got my Mobile 2400+ from newegg yesterday. It is an IQHYA 0402 chip. After I install it on my A7N8 X DLX 2.0, weird thing happened. It refused to post on any BIOS setting except the default one.
That is what happened:
1. I put the CPU on and power on, It posts and say: CPU changed, AMD Mobile XP 600
2. I go into BIOS setting, It shows the default : 14X, 100MHz, Vcore 1.57V
3. I changed to 133MHz, Save, Exit, no post!
4. I disconnect the power cord, clear CMOS, it posts again: CMOS checksum error, default setting loaded.
5. I must go into BIOS setting and chose to load default settings, then save and exit. This time it boot into XP.
6. I restart and set BIOS again, no matter what I changed, even only change Vcore, no post! I must clear CMOS, load default again.

What’s the problem? This board has the same syndrome with my T-Bred 2400+ also, but only happened sometimes. I use 1006 BIOS. It dose show all multipliers (9 to 22) in BIOS. Anyone has the same problem? I used more than 10 different boards before. This Asus board is the worst in term of BIOS problems. Should I RMA it?

Your board is reverting to safe mode. When you go into the BIOS, does it have the 133 setting stored, even though it's running at 100?

When your board doesn't POST, the bios is "smart" enough to revert to safe mode to get it to post. I'd bet it's the same thing that was happening to me. It's heat. That board is VERY picky about heat. The AMD stock hsf will not cut it. Get a better all copper HSF (I got a Kingwin from Newegg for $11) and I've had no problems at all since then.

Mine did this a lot for a while, ended up RMA'ing it to Asus. I had a lot of problems with these boards until I cooled off my cpu. Now it runs rock solid. (I'm running at 47C with full load now- folding 24/7.)

What temp are you at? That board seems finicky with temps. It took me a year to figure the problem out but in the end it's all fine now.

I am experiencing the same thing, "CMOS Checksum error"

I was doing a hot flash to flash a Abit bios chip using my Asus board and the flash did not work.

I can reset CMOS with battary and jumper, and I can get into bios to make changes but when I try to save bios, I get nothing but a blank screen.

If I again attemp CMOS reset, I am back to bios but still unable to save changes. If I clear CMOS and just let it try to load I get a CMOS checksum error at end.

I tried unsuccessfully to fix this problem by reflashing my Asus Bios chip to 1007 but again I am experiencing this CMOS checksum error.

Did I permanently kill my board? Is there something I can do?

Hi, there! My board turns out ok finally. I think yours is not dead yet. This Asus baord is very picky. You need set everything in correct range
, otherwise you get a black screen. You BOIS setting do saved in CMOS . Try this:

1. Clear CMOS, entry BOIS and load default.
2. Then save and exit. If it post and you can boot into windows, your board is definitely works.

3. Entry BOIS, set: Mutiplier: Auto, FBS: 166MHz, Memory: By SPD, AGP: 66MHz. Vcore: 1.75V, Then save and restart. You should be fine.

If it works, try OC it little by little.

I tried to load default, but it will not post when I save.

FIXED IT! PHEW!!!

I forgot I had SATA Raid, it was trying to load OS with HD...lol

All is cool. I just cancelled an order to replace my mb. I feel stupid about the SATA. Thanks for helping me. I did take your advice to recheck everything in Bios and that's when I discovered the default was set to HD, instead of SCSI.