Mysterly solved... and I AM AN IDIOT :)

Post #41,452 by cwbrenn 6/6/02 4:24:04 PM Reply	Mysterly solved... and I AM AN IDIOT :) Sheesh. I'm pretty embarrased now. My problem had nothing to do with a power supply, burned out CPU, burned out chip, or anything like that. It was, in fact, an improperly grounded motherboard. This tower has been through 3 motherboards. The first motherboard was a different SHAPE than the next two, and the holes for the middle row of screws that attach it to the case were about an inch off from the next motherboard (and the new one). Just glancing at it, however, you can't really tell, and when I put the new motherboard in I didn't notice that the middle row of metal columns weren't actually lining up with the holes. Miraculously, I used that motherboard for about a year with those posts not doing a damn thing to it. I guess it had been positioned "just right" or something. But I guess the board shifted ever so slightly in the last few weeks, and everything started screwing up. When I put in the new motherboard (thinking the dead fan on the other one had perhaps toasted one of the processors), it didn't work at all. So after cobbling together a frankenstein windows machien based on working parts from my linux box, and reporting initial success here, I started combing over "the wreckage" (my office is quite a sight right now) and I noticed the posts didn't line up with the holes. So I moved them. And now the !@#$% thing works. Good God, I feel like an idiot. :D "We are all born originals -- why is it so many of us die copies?" - Edward Young
Post #41,455 by drewk 6/6/02 4:45:20 PM Reply	This is like the 'made for IE' pages that break in Mozilla It's always been broken. It's just now that something is complaining about it that you notice. === Microsoft offers them the one thing most business people will pay any price for - the ability to say "we had no choice - everyone's doing it that way." -- [link\|http://z.iwethey.org/forums/render/content/show?contentid=38978\|Andrew Grygus]
Post #41,477 by Meerkat 6/6/02 8:13:36 PM Reply	Idiot? Come on! The worst kind of problems to fix are the ones where things fail and you genuinely "Didn't change anything!". So hey, don't be so concerned. And enjoy basking in the radiant light of all that working-motherboardy goodness. Or something :) On and on and on and on, and on and on and on goes John.
Post #41,485 by static 6/6/02 10:32:30 PM Reply	Not an idiot. If anything, I'd say the motherboard makers are idiots for never ever documenting how their boards are supposed to be grounded. Whilst I can't say I've ever had this problem, I [link\|http://z.iwethey.org/forums/render/content/show?contentid=41384\|posted earlier] about a friend who did. And he's experienced at building PCs! So that problem bites even the best of us. Wade. "Ah. One of the difficult questions."
Post #41,516 by jbrabeck 6/7/02 9:02:06 AM Reply	Definitely Not an idiot. I have to concur with Wade. I've been doing this for almost 15 years and have never run into this problem. Now I will be aware of it. So, not an idiot, but a "thank you" for exposing another problem area and suffering through the problem. Come to think of it, I may have a system that I took out of service because I couldn't fix it... symptoms are very similiar to your's. Hmmmm, now if I can only remember where I stashed it.... [link\|mailto:jbrabeck@attbi.com\|Joe]
Post #41,601 by Ashton 6/7/02 7:06:47 PM Reply	Oddly though - I recall that at least one 'manual' with a 486 mb, pointedly referred to 'THE Grounding point' and with a terse use of ~ phrases like .. "to prevent ground-loops" .. "ensure a hi-current ground return, use a star-washer" etc. It carefully advised using insulating washers for the mere mechanical mount points. That stuck in my 'lectronic memory as being: Sound Advice. But then.. I tend to read these things 'cause I'm lazy. I'd rather read about What Can Go Wrong than sleuth. Still - only remember this stuff being hinted at once (in maybe a mere couple dozen or so overall installs = pittance). Ashton
Post #41,702 by static 6/9/02 2:14:42 AM Reply	That's rare! I've never seen any such advice in motherboard manuals. And I've built more than a half a dozen over the years. Wade. "Ah. One of the difficult questions."
Post #41,706 by Andrew Grygus 6/9/02 2:31:35 AM Reply	Don't recall ever seeing "ground loop" mentioned . . . . in regard to computers, though it certainly is in audio stuff, where a signal can still be "significant" at a very tiny % of the main signal. Many older boards were, however, essentially "single ground point" with one screw up near the power connection and everything else supported by plastic standoffs. The three 200-MHz and 233-MHz AMD K6 boards I just stripped out of computers one of my clients made me haul away are like that. Current motherboard thinking seems to be "ground plane" with as much sheet within the board as possible and 7 to 9 ground to chasis points. Plastic motherboard standoffs are no longer used at all, it's all "bolt to metal" now. [link\|http://www.aaxnet.com\|AAx]
Post #41,792 by Ashton 6/10/02 1:59:14 AM Reply	Could be mfg.-memory on that phrase.. After all - it is an analog phenom. (Could screw up small biases though) But now I'm curious, so will make trip to basement and see if one of the manuals survived.. As to that 'encapsulated ground plane' thingie - recall a few years ago in ED (Elec. Design) a treatise on the mb difficulties of getting the design s/ware to produce a decent model for producing good pulse rise-times (article was re RAMBUS at the time - showing GHz fancy 'eye' displays on a $60 K HP scope). Outta my league. But RAMBUS sounded like a loooser, even then - you Needed that HP just to check a module! they said; forget the little $1-400 memory tester boxes. Ugh. Not surprising then, that the new mbs might want multiple good edge grounds, even if the GHz stuff is localized - the memory sockets spread it out. Yawn.. we're all getting jaded with GHz stuff everywhere, while nobody knows Ohm's Law. Ashton

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