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Loss of fan control & sensors, reboots to code b1, then 76

Bob_760
Level 7

‎06-23-2016 09:16 AM - last edited on ‎03-06-2024 02:06 AM by Community Admin

I've been having this intermittent problem it hasn't been effected by bios updates, clearing cmos or any motherboard settings. I can have everything at factory default, xmp, overclocked stable at 3.9, 4.0, 4.5 with various voltages and settings. Nothing eliminates it.
Everything will run fine and pass memtest, intelburntest, realbench, superpi, whatever you want to throw at it. Not a problem.
After a while (ranges from hours to days) the fans will stop working and freeze at whatever speed they were running. Ai Suite will show two dots on it's fan graphs, a transparent one where the fan should be, and a solid (normal) one where the fans actually are. In addition no utility will be able to read T_Sensor 2 or T_Sensor 3. At this point everything is still stable, as long as i manually adjust fan speeds as necessary to keep things cool.
Sometimes this happens while idle, other times under full load, and everywhere in between.
If I restart at this point it hangs with POST code b1, restarting further hangs with POST code 76.
If I turn off the PSU and wait for the lights to turn off then turn it on again it will say "Overclock Failed" etc. even with system defaults, and after confirming settings everything will work fine again, until it happens again.

Any ideas?

Thanks,
-Kurt
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4 REPLIES 4

samboy87
Level 9

‎06-23-2016 10:02 AM

Hello Bob_760 welcome to the forum!

Maybe a corrupted BIOS? what firmware version do you use? and have you updated the Bios lately? if not, i would try to update to the latest version.
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Bob_760
Level 7
In response to samboy87

‎06-23-2016 11:57 AM

Thanks for the welcome!

I've been running 2101. It has occurred with previous versions as well.
I've tried flashing from the bios utility and with usb bios flashback without changes.
I've reset defaults with the button, in bios, and by removing the battery until it clears everything.

I did try 3101 but the computer was restarting all the time like people in this thread, no idea if it solved the problem since the computer never stayed on long enough.
I tried bumping up my ram voltage after reading that thread but it didn't solve the problem for me.
http://rog.asus.com/forum/showthread.php?85355-Random-restarts-with-3009-and-3101

I went back to 2101

I saw that 3102 came out but I searched and found this thread first. It doesn't instill me with a lot of confidence so I haven't tried it.
https://rog.asus.com/forum/showthread.php?85892-New-BIOS-3202

I've always kept the bios up to date in every computer I've built, I'm not new to this, I started overclocking with a Pentium II 450mhz, but I can't think of anything I could be doing wrong.
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Bob_760
Level 7
In response to Bob_760

‎06-27-2016 11:10 PM

Well I've re-flashed 2101 to no avail then finally updated to 3102, so far so good? It sometimes takes a while to mess up so we'll see.

Edit: After a few hours with 3102 it seemed to have a similar failure, my top fans had 0 rpm readout despite spinning and my pumps went to 100% duty cycle and couldn't be controlled. I guess I should enjoy the improvement that it failed safe instead of overheating? I was also able to restart without issue.
[All of this is at completely stock non XMP testing]

Edit: Now it's crashed under load then restarted with b1, restarting it came up 00 which surprised me, then restarting subsequent times went back to the usual 76. As always turning off the PSU, waiting, and rebooting got everything going again.

Edit: Re-flashed 3102 again getting random restarts.

Edit: After reading threads about 3xxx BIOS I tried running XMP profile (The thought is 3xxx may be unstable below 2400mhz mem, fortunately I happen to have 2400mhz xmp) Now it's stable enough to run long enough to recreate the old problem exactly as stated previously. Only change is sometimes it crashes under load after the fans stop working 😄
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Bob_760
Level 7
In response to Bob_760

‎07-04-2016 09:16 AM

I'm now running a mild overclock (4.0 with minor vcore increase) with XMP at this point, if anyone has seen this behavior with an unstable overclock please chime in with any ideas for increased stability. I suppose I don't care if the PC doesn't work at BIOS defaults if I can tune it to be stable.
As stated previously I've used countless stability tests for cpu, gpu, and memory without incident. This is the only issue.
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