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scott wrote:
>> A failing power supply causes a system to act erratically more often
>> due to switching noise not being filtered out than to low voltage or
>> current.
>
> Switching noise (eg at 50 Hz) is just out-of-spec voltage for a few
> million CPU cycles :-)
I would imagine it's more likely to upset the video or audio systems
than the CPU itself...
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Warp wrote:
> When your PC starts misbehaving clearly due to some hardware failure,
> the very first thing you do is check the PSU.
>
> In my experience 90% of PC hardware failures are caused by a failing PSU.
This does not match my experience.
I have seen PSUs die, and computers do very, very strange things as a
result. But it's fairly rare. Rarer than, say, HD failures or fan failures.
has an expensive brand-name "performance" PSU - not that that
conclusively proves anything.)
> The symptoms can be extremely varied, all the way from the diverse BIOS test
> failing (such as the CPU or RAM tests) to random crashes and reboots, as well
> as the booting process failing seeminlgy due to some disk error.
>
> If your PSU is failing, hardware tests (performed by BIOS or third-party
> software) are completely unreliable and tell you absolutely nothing.
I ran a RAM check, and it consistently tells me that one specific area
of RAM isn't working. Every time I run the test, it complains about the
same chunk, fairly high up in the computer's address space.
If the power supply was unstable, I'd expect to see random glitches all
over the place, not just in one confined area.
The OS behaviour I'm seeing is also consistent with a RAM fault;
initially the system works fine, until it tries to use that chunk, at
which point it starts to malfunction spectacularly.
Perhaps more importantly, it will take me about 30 seconds to determine
if a fried RAM module is the problem. Rewiring the PSU would take far
longer, and the only PSU I have to test with *is* insufficiently
powerful to run the PC.
So in summary, I think I'm looking at a broken RAM module, not a PSU
fault. Although I guess it's possible a faulty PSU might be what _broke_
the RAM module in the first place...
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> Perhaps more importantly, it will take me about 30 seconds to determine
> if a fried RAM module is the problem.
So is it then?
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scott wrote:
>> Perhaps more importantly, it will take me about 30 seconds to
>> determine if a fried RAM module is the problem.
>
> So is it then?
I don't know; ask me when I get home. ;-)
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Invisible <voi### [at] dev null> wrote:
> I have seen PSUs die, and computers do very, very strange things as a
> result. But it's fairly rare. Rarer than, say, HD failures or fan failures.
So far I have had 4 PSUs break down in my computer, plus one in an iMac
at work. Three of these cases presented with random symptoms which at first
didn't raise suspicion that the PSU was the culprit (in the other two cases
the PSU simply outright stopped working, one of them with a loud snap).
So far the only other hardware failure I have ever had is a bunch of bad
sectors in one HD.
> I ran a RAM check, and it consistently tells me that one specific area
> of RAM isn't working. Every time I run the test, it complains about the
> same chunk, fairly high up in the computer's address space.
I tell you: Check your PSU first, *then* consider other possibilities.
It doesn't matter how random or how consistent the errors might be.
It might well not be the PSU, but it doesn't hurt checking it, and if it
so happens that it is indeed the PSU, it will save you a lot of work and
wasted money when you don't have to test anything else.
--
- Warp
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On 5/27/2010 3:39 AM, scott wrote:
>
> Switching noise (eg at 50 Hz) is just out-of-spec voltage for a few
> million CPU cycles :-)
>
>
Switching noise is in the kHz range, not 50/60 Hz. Google "switched
mode power supply" for more details on how they operate.
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>> Switching noise (eg at 50 Hz) is just out-of-spec voltage for a few
>> million CPU cycles :-)
>>
>
> Switching noise is in the kHz range, not 50/60 Hz.
My point was that any "noise" from the PSU is the same thing as out-of-spec
voltage.
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>> Perhaps more importantly, it will take me about 30 seconds to
>> determine if a fried RAM module is the problem.
>
> So is it then?
Yes.
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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I unclipped the two 1GB memory modules, and all of the memory test
errors vanished. I have now booted up Windows, and all of the bizare
behaviour has vanished. My PC works like normal again.
Woo!
that only *one* of these two modules is defective, and I can keep the
other one...
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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