[mythtv-users] Hardware death - CPU vs motherboard?

Tom Dexter digitalaudiorock at gmail.com
Sat Oct 24 17:01:36 UTC 2009

On Sat, Oct 24, 2009 at 12:28 PM, Kawayanan <kawayanan at gmail.com> wrote:
> Well, I just checked to see if I could test the PSU.  I have two others in
> the house, but either my other computers are sufficiently old to be
> different (very possible), or the PSU on this Asus Barebones is
> non-standard.
> I can't test the PSU in the way you describe because the BIOS screen never
> comes up.  It never gets that far (fan spin, nothing else happens).  As for
> RAM tests, again, I can't get to BIOS, let alone memtest86 (I also use
> UBCD).  It had two sticks of RAM and neither one worked alone.  On top of
> that, a brand new stick of RAM didn't work either.  I find it hard to
> believe all are bad.
> I think its PSU, motherboard, or CPU.  The problem is I have no way of
> figuring out which one.  This may just be the final death of this machine...
> Thanks again
> On Sat, Oct 24, 2009 at 11:44 AM, Andy Colson <andy at squeakycode.net> wrote:
>> George Mari wrote:
>>> On 10/24/2009 07:35 AM, Kawayanan wrote:
>>>  >
>>> [deleted]
>>>> My question is whether there is a way to determine if this is a CPU or
>>>> motherboard problem?  I don't have access to a different CPU to test,
>>>> and I
>>>> don't want to buy a CPU and have it turn out to be a motherboard
>>>> problem.
>>>> If its a motherboard problem, I guess that means starting over with a
>>>> effectively new system (the Asus is a barebones with most everything
>>>> onboard).
>>>> Any suggestions?  My wife and kids are missing DVR. :(
>>>> Thank for any help!
>>> It may be a power supply problem.  If you have another system you can
>>> temporarily spare, swap PSUs, or move the suspect motherboard into an empty
>>> case, if you have one.
>>> Power spikes, in my experience, tend to kill PSUs first, then
>>> motherboards, then CPUs, in that order.
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>> Agreed.  I'v had more power supply's die than anything else. (but moving
>> power supply is lots easer that moving motherboard)
>> One way I have tested the power supply is by watching the bios screen that
>> shows you the cpu fan speed and power line readings.  (Where it shows you
>> 3.5V and 6V, and the fans at 1500 rpm or whatever... not sure what the
>> screen is called)
>> The voltage should remain steady.  If it jumps (it'll be very quick and
>> hardly ever happen, so you have to stare at it for a while) then its a bad
>> power supply.
>> To test the cpu vs memory, take all but one of the memory chips out, and
>> run memtest86 on it.  (I use UBCD)  If the pc crashes and dies its probably
>> cpu/motherboard.  If the scan runs ok its probably memory.  Test each memory
>> chip, one at a time by itself.
>> Also if it smells hot, its probably overheating.  If its overheating you
>> can smell it, and feel it... its really hot.
>> -Andy
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You may be able to test the power supply like this:


I recently had the power supply go on my frontend (a Dell 4700c).  It
had a blinking amber power button which can either mean a bad PSU or

I tried doing a test like the one linked above...unlike some Dells the
PSU on that uses standard ATX power (20 pin).  Oddly enough though, no
matter what I did to ground out that ON pin I couldn't get the PSU fan
to even start, even though the PSU fan did in fact run when plugged
into the motherboard.  Confusing as hell.  I just ended up buying a
power supply and that fixed it.


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