-5 volt runnig at -7+

Ok this is weird. Working on a friends computer with lots of instabilities, reboots, system files disappear, and so on. I've seen this before and tracked it to a bad psu. So, checked voltages... sure enough, -5 is reading -7+ (MBM5). Took a known good psu out of my #2 computer and guess what... still get a -7+ reading and the system is still unstable. New psu is only 2 months old, good quality unit, is identical to the one in my main computer and shows correct voltages in my #2 computer. Anybody have any ideas? This one really has me scratching my head.

Oh yeah, had to replace the video card cause it was toast, lots of artifacts even on post screen... floppy drive was bad also. Plus, I had to replace his cd burner a few months back. This thing has apparently been at least a little unstable from day one but the owner is VERY computer illiterate and didn't even know that these things shouldn't be happening, getting helpful info from him is like asking a chimp to do calculus.
I'm thinking mobo problem...

P4 1.5 (Willamette core)
Azza P4X2-AV motherboard
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More about volt runnig
  1. The -5v line isn't important to the stability of your system, and is misread by most programs anyway.

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    <font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>
  2. OK, I'll buy that for now... So, what is causing the problems with the system? It runs OK when it is warm but will not boot properly when cold. I get various file not found errors at (cold) boot as well as spontaneous reboots when not yet warmed up (all signs of a bad psu in my experience). Have installed 98, 2K and XP and get boot problems with all three plus there is this very high failure rate of components, CD-RW, video card and floppy drive all in the last few months. As I said, I'm thinking mobo. Have eliminated every component so far except for that and the CPU itself. Have switched out and replaced all components except mobo and cpu since I only have AMD in my machines. Do have some old Intel stuff but nothing that will work.Have run all kinds of software tests (Sandra,DocMem, and so on). My old (ISA bus) POST Card is useless these days so I'm not able to use it anymore except on old systems (can't afford a new set). Do you know anthing else out there that can really test a mobo and processor? Any ideas would be greatly appreciated.

    <P ID="edit"><FONT SIZE=-1><EM>Edited by silverwizard on 10/26/04 04:36 PM.</EM></FONT></P>
  3. Missing files? Sounds like a VIA chipset problem. Does your board have a VIA chipset?

    <font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
    <font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>
  4. Files are not really missing. System will boot up after a couple of tries, once it gets warm in other words. Yes, his mobo has a VIA chipset, VT8753/A/E Applolo P4X266/A/E according to Everest Home Edition... Southbridge is stamped VT8233, Northbridge has heat sink. An article on Hot Hardware calls it the Via P4X266
    http://www.hothardware.com/viewarticle.cfm?articleid=80&catid=3
    Have loaded the newest VIA drivers also. (tried the old ones too, no difference)
    What VIA problem are you refering to?

    <P ID="edit"><FONT SIZE=-1><EM>Edited by silverwizard on 10/26/04 05:41 PM.</EM></FONT></P>
  5. Around 1/10th of systems I've built have had VIA chipsets. I've built over 1000 systems, so that's 100+ VIA chipset boards. Out of all my systems, around 20 have had hard drive controller problems resulting in lost or corrupt files, or access problems. All 20 of those were VIA chipset boards. What this leaves me with is around 1/5 of my VIA based systems having intermittent drive controller problems that I haven't been able to narrow down to any specific chipset model or board. Most of these boards eventually behaved better after trying several different BIOS versions or hardware configurations or driver versions.

    <font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
    <font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>
  6. Interesting bit of info there. Not sure if it applies here since the files are not lost or corrupt. Only time there is any problem at all is at cold boot. Warm boots go just fine, everything works pefectly as long as the system is left active. I'm having it turn off the monitor and hard drive after 1 hr. idle and it works like a champ. Haven't tried system standby yet (got that starting 15 min from now, hope to find out in about 1 1/4 hrs, allowing 1 hr for complete cool down).
    At any rate, I believe that it is a mobo problem and it could be the chipset. I have never used a board with this particular chipset, matter of fact, I would never have built a system with this mobo anyway.
    Guess I'll try flashing the BIOS and see what happens. He's kind of anxious to get his box back so if that doesn't work I think I'll put a new mobo in it and call it quits.
    Thanks for your suggestions.
  7. Whoa! Just put the psu from the rouge PC in my #2. +12 volt line (yeah, I know it's cool to call it "rail" instead) was running at 13+ and 3.3 was fluctuating between 2.85 and 5.99... Not sure but I kinda think that this psu was at the root of my friend's probs. (tounge-in-cheek here) Sorry, I had moved parts all around but didn't do this till tonight. D-oh!
    Still gonna do the flash, hoping that it MIGHT help... not much hope but... who knows? I have had more than one "miracle" happen in this biz. (not really in the biz anymore, just doing it for fun and beer money these days).
    Again, thanks for all your help.
  8. Let's ponder the possible negativities of flashing a board with a bad power supply...what's the worst that could happen, blown CMOS and bad board? Heck, go for it!

    <font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
    <font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>
  9. Actually, it now has a good psu. I'm leaving my 400w in it and dropping back to an older 350w in my #2 since it really doesn't need the 400. Owner says go for it, so as soon as I've had my coffee I'm gonna do it. After the things I have read on line about this mobo, I'd rather see a better one in this system anyway and the owner agrees. Matter of fact, even if this works, he is thinking that he will upgrade mobo and processor soon anyway. Besides, what is life without the occasional gamble anyway?
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