Question MoBo no post ...cpu compatibility or dead ?

Rayzer88

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Dec 30, 2015
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Hi all,

I’ve been making up a pc out of used parts but I cannot get it to POST or get into the BIOS

I've tried all the usual suspects (removed RAM, RAM in different slots, checked all cables, no video card, removed battery, cleared CMOS etc) and still it won't post

Narrowed it down to PSU, CPU or a dead Motherboard. Tried another PSU and still nothing

Using a i5-4690k in an Asus B85m-e Motherboard. I've seen somewhere that this motherboard may need a bios update to support this CPU but how do I do that without being able to enter BIOS? Or am I clutching at straws and likely had a dead motherboard?

ANY help you can give me would be much appreciated...I've been tearing my hair out for 2 nights haha
 

PC Tailor

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I've seen somewhere that this motherboard may need a bios update to support this CPU
Yes it does - it needs BIOS version 2001 at least.

how do I do that without being able to enter BIOS?
You can't. You need a previous generation compatible CPU first.

In effect, you need a particular BIOS for the components and BIOS to be able to detect the CPU in the first place, in it's current state, your PC can't identify/use the CPU installed, therefore it cannot POST/ boot to BIOS. So you have to be able to POST normally, then update the BIOS, which requires an out of the box compatible CPU. Or a BIOS button feature, which only the latest boards will have.

This is assuming it is indeed the BIOS that's the problem, which if it has never been updated, it likely is.
 

Rayzer88

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Bit of an update but worried it's not a good one.

An old compatible celeron arrived today and I managed to get into BIOS and update it. All good, booted up again and navigated the new BIOS just to check all was working as it should

I fitted the 4690k and unfortunately no POST again so I'm concerned it may be a dead CPU.

I reinstalled the Celeron again without any problems, and the second try with the i5...nothing

Likely a dead CPU?
 

PC Tailor

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Bit of an update but worried it's not a good one.

An old compatible celeron arrived today and I managed to get into BIOS and update it. All good, booted up again and navigated the new BIOS just to check all was working as it should

I fitted the 4690k and unfortunately no POST again so I'm concerned it may be a dead CPU.

I reinstalled the Celeron again without any problems, and the second try with the i5...nothing

Likely a dead CPU?
Could well be unfortunately, especially if you definitely installed BIOS required.
May be worth a quick visual inspection of the CPU array to see if there is any contamination / damage.
But if the other CPU works fine and the BIOS is current, then you've only really got the one culprit to look at.
 

Rayzer88

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Just got back into the BIOS and re-checked and yes it is the most recent one dated 2018

Nothing seems all that untoward upon visual inspection although should I be worried by the "dents" shown in the picture (this is from the listing)

Looks like it could be from the retention bracket, but I didn't think there's enough force in the bracket to cause those dents?
 

PC Tailor

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It wouldn't necessarily look like damage I would suspect to be a big issue, but the condition of it might tell how well they looked after it, which is where there may be a problem. The retention bracket does hold down with some force, but when done carefully shouldn't cause damage.
 

Rayzer88

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Yeah that makes sense I suppose

Clutching at straws but I'm assuming there's nothing I need to do in the BIOS before fitting the CPU?

Just double checked and the BIOS seems to be correct/compatible
 

Rayzer88

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I've requested a return/refund. Can't possibly see what else could be the problem when the Celeron boots up fine, and the BIOS is up to date
 

Rayzer88

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Hopefully the last one on this !

what is the likelyhood of bent pins affecting one CPU but not another ?

I can’t tell for certain if any are bent (yet) but a replacement CPU arrived today and just as before it won’t POST but the Celeron still boots up fine
 

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