on one of my computers (440lx/PII-333)that I'm trying to troublehoot (there is no signal to my monitor), the metal screws, the metal ring around the screws, as well as the brass or brass colored standoffs they go through, all have continuity with the case. Is this a correct situation, or a problem? I sometimes hear of a 'motherboard shorted to ground'. When is this a problem ? What exactly gets 'shorted to ground'? Can someone shed some light on this for me?
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Motherboard and continuity question 1
- Thread starter fenix
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It is normal for the metal rings and screws to have continuity with the case. Mobos short when a live part of the board comes in contact with the chassis. I have known this to occur through the mountings, if in doubt remove the mobo, place it on a non-conductive surface and power it up there. All you need is a powersupply, vid card and switch connected (if ATX). As well as CPU and RAM of course.
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- #3
thx for the reply, what I'm trying to troubleshoot is this. This particular computer has not been used for about 3 months. I had a 120 day trial version of W2K on it, which has long ago expired. I turned it on yesterday to see what message it would give me and if I could possibly fdisk and reload the eval version again or if not, to put 98 back on it.
Well, no picture and the monitor led light didn't even flicker. The monitor is a known working monitor and i removed the AGP card and installed it in another computer and it worked well. It was suggested that it was common for the AGP slot to go bad and to try a PCI card instead. So I bought a couple of used ones (was told that they were in working condition), but I might have to load new drivers. Came home, neither one got the monitor to display. Plus, I don't really understand how they would work without having drivers loaded, unless somehow generic VGA drivers load from the BIOS, or windows. But could the fact that the OS is expired be affecting this all?
The machine was working perfectly the last time I used it a few months ago, and it hasn't been dropped or damaged in any way. There are 2 other things that may come into play.
I always just used the front switch to turn the comp on, (actually I didn't even realize that there WAS a rear sw on the power supply until lately). Now, when I turn the rear switch on, the computer comes right on (hard drive spins up and cpu fan spins). (It seems like the front switch is always making a circuit to the board.) I removed the connector from the front switch at the mobo and the machine just powers up the same way like when the connector was connected. Also, the front switch will power the machine off if I hold it in for about 5 secs, but when I release it, it powers back up.
The other thing, is that one time after I first got the computer, it powered up with beeps that I looked up and were signaling a video problem. I removed and reseated the AGP card and it worked fine after that. This time, even though the monitor doesn't come on, I don't get any beeps.
Should I assume that the motherboard is bad, or does anyone have any other ideas? thx, sorry for the length of this, btw, it's an AL440LX/PII-333. I'm thinking maybe the battery went dead and I lost my cmos settings? Not sure of the BIOS manufacture, but I do see a small square chip that says Intel on one end and handwritten font that says flash, about 1/2" X 1" near the corner of the board adjacent to the 2 ISa slots. Didn't think Intel made BIOS chips but ? And there's not much activity after the initial spin up of the hard drive, so maybe it I could see the monitor, it would be telling me that the OS evaluation period is expired and cannot be loaded. thx for any help.
Well, no picture and the monitor led light didn't even flicker. The monitor is a known working monitor and i removed the AGP card and installed it in another computer and it worked well. It was suggested that it was common for the AGP slot to go bad and to try a PCI card instead. So I bought a couple of used ones (was told that they were in working condition), but I might have to load new drivers. Came home, neither one got the monitor to display. Plus, I don't really understand how they would work without having drivers loaded, unless somehow generic VGA drivers load from the BIOS, or windows. But could the fact that the OS is expired be affecting this all?
The machine was working perfectly the last time I used it a few months ago, and it hasn't been dropped or damaged in any way. There are 2 other things that may come into play.
I always just used the front switch to turn the comp on, (actually I didn't even realize that there WAS a rear sw on the power supply until lately). Now, when I turn the rear switch on, the computer comes right on (hard drive spins up and cpu fan spins). (It seems like the front switch is always making a circuit to the board.) I removed the connector from the front switch at the mobo and the machine just powers up the same way like when the connector was connected. Also, the front switch will power the machine off if I hold it in for about 5 secs, but when I release it, it powers back up.
The other thing, is that one time after I first got the computer, it powered up with beeps that I looked up and were signaling a video problem. I removed and reseated the AGP card and it worked fine after that. This time, even though the monitor doesn't come on, I don't get any beeps.
Should I assume that the motherboard is bad, or does anyone have any other ideas? thx, sorry for the length of this, btw, it's an AL440LX/PII-333. I'm thinking maybe the battery went dead and I lost my cmos settings? Not sure of the BIOS manufacture, but I do see a small square chip that says Intel on one end and handwritten font that says flash, about 1/2" X 1" near the corner of the board adjacent to the 2 ISa slots. Didn't think Intel made BIOS chips but ? And there's not much activity after the initial spin up of the hard drive, so maybe it I could see the monitor, it would be telling me that the OS evaluation period is expired and cannot be loaded. thx for any help.
1st, the expired OS should not have anything to do with the problem.
2nd any working video card should display your BIOS info etc, no drivers needed.
3rd, in the case of a dead battery you should at least get the POST and an error message on screen.
I would suspect from what you say about the switches that the motherboard has developed a hardware problem, however it could also be the PSU. I would not think that it is either the CPU or RAM. Maybe someone more knowledgeable than myself could step in here.
2nd any working video card should display your BIOS info etc, no drivers needed.
3rd, in the case of a dead battery you should at least get the POST and an error message on screen.
I would suspect from what you say about the switches that the motherboard has developed a hardware problem, however it could also be the PSU. I would not think that it is either the CPU or RAM. Maybe someone more knowledgeable than myself could step in here.
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- Jan 1, 1970
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I agree with mulga... Assuming that you have checked for the unlikely event of a screw becoming jammed underneath the motherboard, you're not left with many options. Check that the front panel ON/OFF switch is indeed making and breaking when it ought to, and check the RESET switch - I have known this to be permanently shorted out and give this kind of problem. Does the power-on l.e.d. light up? You could try removing all other cards and disconnecting all drives from the motherboard. Remove drive power connections as well, just to see if anything else is pulling down the system. Try re-seating the CPU as you're not getting any beeps from the system, and clear CMOS just to make sure that isn't screwing it up. Definitely worth trying another known good PSU though...
Good luck!
ROGER - GØAOZ.
Good luck!
ROGER - GØAOZ.
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- #6
thx for the replies, I took out the sound card and nic , and r & r'd the ram and PI connector and p/s (so I could reseat the processor) and everything works fine. I was a little surprized that I heard a beep after POST because the 3" speaker was still disconnected, but realized it came from the little 1/2" cylinder that I guess is a built in mobo speaker (in the corner of the board). Not sure which action did it, but suspect it was reseating the processor as rojer suggested. Was also glad to see that the 120 day evaluation copy of W2K still booted up, (going on 5 months!)I'm wondering now if it's 120 days of usage instead of 120 days since initial installation. Or maybe MS gives a grace period. Anyone know? thx again.
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