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Computer wont post, immediately shuts off

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sirhotalot

Registered
Joined
Mar 6, 2003
[SOLVED] Computer wont post, immediately shuts off

Specs:

Asus Sabertooth 990fx R2
AMD FX-8350 cooled by a Cooler Master Seidon 120v
GeForce GTX 770, it's fine as far as I know
Samsung SSD 840 Pro, Samsung's diagnostic tool says it's fine
CORSAIR HX Series HX750 750W 80 Plus Gold

It was assembled in April 2014. I had to send the first mobo back the day I got it as it was causing weird issues and I'm currently using the replacement they sent me. For the past few months I've been getting errors on boot if it even boots at all. It gives me a warning about the CPU fan and then shuts off, other times it wont even make it to post. A google search shows that a CPU fan warning with this mobo can mean just about anything. I'm using a Cooler Master Seidon 120v. For some people they were having issues with their RAM, I tried moving the RAM into different slots and that hasn't helped but I haven't tried running with individual sticks. It's difficult to determine because the problem comes and goes, it can be weeks between issues. It's not a heating issue, it happens in the morning when I first turn it on and runs fine for the rest of the day. I updated the mobo's BIOS about a month ago. It hasn't helped.

Edit: I forgot to mention I have it set to ignore fan errors in the BIOS. It doesn't give me the errors anymore, but occasionally it will fail to post. Could it be the motor failing?

Edit 2: SOLVED. Unplugged the liquid cooler from the CPU_OPT slot and plugged into a CHA slot. Upped the voltage to the CPU slightly.

Edit 3: Lowered the voltage, everything still works. CPU_OPT header must have an issue.
 
Last edited:

EarthDog

Gulper Nozzle Co-Owner
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Dec 15, 2008
Location
Buckeyes!
Your cooler, do you have it or anything connected to the CPU fan header? Can you disable the low speed warning or monitoring of that header in your BIOS to stop getting the error to see if that helps?
 

Mr.Scott

Beamed Me Up!
Joined
Jun 9, 2013
It IS a heat issue. Pump on your cooler is intermittently binding. That is why you're getting a low fan speed code, assuming of course you have the pump plugged into your CPU fan header on the board.
 

Johan45

Benching Team Leader Super Moderator
Joined
Dec 19, 2012
I agree, even if you had a low speed warning you should be able to get to BIOS or even OS. But since it's crashing even at post there's something else going on.
 

Mr.Scott

Beamed Me Up!
Joined
Jun 9, 2013
CM had a problem with pre-mature pump failure on the earlier Seidon's. They have since made changes to correct this.
 

EarthDog

Gulper Nozzle Co-Owner
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It would still take a while... at least enough to get through and POST if it was a bad pump (assuming this was a 'cold' start).


EDIT:
I agree, even if you had a low speed warning you should be able to get to BIOS or even OS. But since it's crashing even at post there's something else going on.
That's what I get for getting my boys breakfast and not hitting post, LOL!
 

EarthDog

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Location
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Wonder why it worked on mine for a few minutes... 5820K at 4.5GHz in fact... and past generation CPUs........ I can see that behavior is there wasn't a block on it with water in the loop... not so much with a block on it and water in the loop.
 

Mr.Scott

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Joined
Jun 9, 2013
Wonder why it worked on mine for a few minutes... 5820K at 4.5GHz in fact... and past generation CPUs........ I can see that behavior is there wasn't a block on it with water in the loop... not so much with a block on it and water in the loop.
No idea. I can only tell you what I've seen on my own Sabertooth and 8320. Custom water, pump locked up, post beep, instant shutdown.
 

EarthDog

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I can only tell you my experiences over the past 15 years as well. I have never seen a CPU not be able to POST that is in a loop with the pump off. Oh well. Ive never owned an AMD FX, but plenty 'just like it' output wise.
 

Mr.Scott

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Jun 9, 2013
Not disagreeing with you man. There's a lot of stuff I've never seen either. :)
 
OP
S

sirhotalot

Registered
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Mar 6, 2003
I forgot to mention I have it set to ignore fan errors in the BIOS. It doesn't give me the errors anymore, but occasionally it will fail to post. Could it be the motor failing?

Edit: There's 2 CPU fan plugs in the mobo. One is 'CPU FAN' and the other is 'CPU OPT'. I have the motor plugged into CPU FAN and then that fan connected to the radiator in CPU OPT.

http://cdn.overclock.net/3/3f/3f24b9b7_sabertooth-990fx-r2-overview1.jpeg
 

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EarthDog

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Occasionally? So sometimes it works just fine? Things work fine in Windows when it gets there?
 
OP
S

sirhotalot

Registered
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Mar 6, 2003
Occasionally? So sometimes it works just fine? Things work fine in Windows when it gets there?

As far as I can tell the computer runs fine when it boots. The failure to post doesn't always happen, I can go weeks without an issue.
 

trents

Senior Member
Joined
Dec 27, 2008
You might look at bumping up the CPU VID. These kind of things can be caused by the starting voltage of the CPU being too low. Is the system overclocked?
 

EarthDog

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As far as I can tell the computer runs fine when it boots. The failure to post doesn't always happen, I can go weeks without an issue.
so, when in windows, it never shuts down, correct? Just on post it sometimes doesnt work? If thats the case, id move my money off the pump (not that mine was there) and look more at the board/cpu.
 
OP
S

sirhotalot

Registered
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Mar 6, 2003
You might look at bumping up the CPU VID. These kind of things can be caused by the starting voltage of the CPU being too low. Is the system overclocked?

It isn't overclocked that I know of. I believe with this motherboard and this CPU it defaults to a slight overclocking but I disabled that once these issues started. I'll see if I can increase the VID. What's a safe increment to increase it by? Currently it's running at 1.3-1.42v.

so, when in windows, it never shuts down, correct? Just on post it sometimes doesnt work? If thats the case, id move my money off the pump (not that mine was there) and look more at the board/cpu.

It never shuts down once it's on. The other day I put it into sleep mode instead of shutting it off and when I came back in the morning and turned it on it shut off after a few seconds. I don't know if that counts.