From: Brett Russ <bruss@alum.wpi.edu> Subject: Re: [Wlug] help diagnosing PC issue: suspect power supply To: Worcester Linux Users Group <wlug@mail.wlug.org> Message-ID: <CAGcHgFN4odSRHmS=jjYuvEDy1myRMOgKEYxy0bWu9e4-3V9i7A@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1

On Mon, Oct 1, 2012 at 7:57 AM, Brett Russ <bruss@alum.wpi.edu> wrote:

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On Sat, Sep 29, 2012 at 6:19 PM, Chuck Anderson <cra@wpi.edu> wrote:

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I agree that the power supply is suspect. You can measure the voltage

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Alternatively, it may be easier to just try a replacement.

I have a new one on the way. I'll reply here with the results.

Well, brand new power supply and the system behaves the same problematic way as before.

So next try is the memory, as another list reply suggested. I've had memtest86 running against both DIMMs for 47+ hours and counting, 70 total passes so far, and 0 errors. Remember I'd already tried removing first one DIMM, then the other, and the problem repro'd either way. So by these measures it'd seem the memory is OK? I know some mem problems take days to show up so I'll just leave this running for a couple more days anyway.

Not much more I can do here, as I've seen repros with most everything else unplugged so I'm now thinking it must be the motherboard. Perhaps I will try reseating the CPU--haven't done that yet.

Recall the system is having trouble POST'ing: it hangs at various points before BIOS POST completes, i.e. I don't get a confirming 'beep' at end of POST and in some cases the monitor won't wake, other

cases the BIOS splash screen stays splashed, etc. The full original email is here: http://mail.wlug.org/pipermail/wlug/2012-September/008059.html

Anyway, if anyone has other ideas here I'd welcome them.

Thanks again, Brett

Hi Brett, You sound pretty convinced this is a PC hardware problem. I think I missed the earlier discussion, but how exactly do you know this is hardware at fault (vs anything not hardware at fault) and how certain are you? Have you tried running a "bootable operating system" via a CD or DVD drive as a diagnostic step (will it boot Ubuntu or another from the optical drive)? If CD/DVD boot is out, there are thumb drive bootable images also. I would start here and rule out everything that is not hardware. As a test, if a different O.S. than Ubuntu 11.10, runs well (except slower) from an optical drive, your hardware is likely fine (and instead have an Ubuntu 11 or app or driver problem). Step only takes a few minutes and is very telling (and well worth it IMHO). This step will likely tell you if it is hardware vs everything else. So if you can assure yourself it is hardware 100% ... All the PC hardware I have worked on in the past years is pretty much self diagnosing/reporting. In this case, your job if you choose to accept it, is to "read and decipher what the motherboard is telling you at boot up". To speak the language of your motherboard, you need to check for any of the following information: External to case, Rear facing LEDs (often have many and are multi-colored) On motherboard LEDs, viewable only inside Beep tones heard at boot up Error or other messages displayed quickly at bootup You need to read the "diagnostics" page of your model's specific PC or motherboard vendor's manual for this specific PC/motherboard to decipher what it is seeing at bootup (based upon lights/beeps/LEDS/etc). Sounds like: You either have two bad power supplies, or this is not the problem. You could have bad memory DIMM(s) that do pass MemTest86 (these test help, but I have seen them pass on bad chips it is a bit of a long shot though). You have changed the motherboard battery and flashed the latest BIOS. Don't rule out a new BIOS being a problem (glitch in install or wrong one or BIOS version problem) You still have a problem that could be hardware or not. You could have an Ubuntu 11 playing well with your motherboard, thus a test of another OS and version... If it was my PC I would next rule out the following in this order: Test and work on whatever the motherboard manufacturer is telling you via lights/beeps/LEDs/boot messages. Ubuntu V11.10, not because I don't like it but trying something else for 15 minutes could tell you something. The current version of CMOS you flashed to the motherboard