Weird Power On problem

[compudog]

I picked up a PC from a client that had a failing hard drive. I ordered a new, bigger drive and some memory (they wanted to upgrade it somewhat).

System is a generic case with a 350W Deer P/S.
Asus P5-99VM motherboard (SiS Chipset with integrated video)
AMD K6/2-500
192 MB PC-100 SDRAM (1 64MB, 1 128MB)
Generic PCI audio
USR Winmodem
NEW WD 20GB Caviar
original WD 8.4GB Caviar

So I get the new parts installed, checked all jumpers on drives etc. Plugged it in, switch power supply to on, press front panel switch. NOTHING. not even a tiny bit of fan rotation. So I go over everything again, same result. I unhook everything, I mean everything, KB/Video cable, mouse, PCI audio, PCI modem, HDD IDE cables, and try again. same thing.

OK, so I put in a new P/S (Antec True 350 that I know works) same result. I pull all the front panel wires off and connect them 1 at a time. OK, the thing starts up. So I think a front panel LED or reset swtich is shorted. So I put what I need back in hook it up, back to square 1. This comp was running fine when I picked it up (except for the funky HDD)

I can get the computer to start if I play with the power switch in back (on the P/S) and the front power button, alternating between the two. I tried a different switch connected to the mobo pins, but no change.

Anyone else have a similiar problem? I think it's the motherboard that's at fault not seeing the power on signal from the front panel switch to tell the P/S to fire up consistently. Any ideas?

 

[RemyCanad]

It sounds like your right.

Have you reset the BIOS yet? Just one more thing to make sure you have a clean slate.

 

[compudog]

I tried BIOS first off. It weird too, the board has a place for the CMOS reset jumper, just no pins soldered on. I removed the CMOS battery and killed the AC power a few times. Right now the PC is installing windows on the new hard drive. Everything that should be in is in, everything connected and it's running fine. I have rebooted it a few times (after FDISK, format, and copy of win98 dir to HDD) but I am afraid to turn it off. I don't know what I'm going to tell the customer. That they need a new mobo and all the work I've done so far is wasted....

 

[dude]

All I could think of is that the speaker/turbo switch is shorting out the reset switch? Other than that, I dunno.

 

[mechBgon]

So the board won't necessarily power on even if you use a direct screwdriver-tip connection between the power-switch pins? I realize you don't want to experiment with that right at the moment

Maybe the PSU is bad, too. Try again with your Antec and see if it behaves.

 

[compudog]

mech, I tried the screwdriver tip thing too. Same result. It's a weird combination of circumstances that will let the thing power up. It behaves the same way with either power supply (and this rig is too crappy to go out the door with an Antec anyway )

I can get an Athlon XP and motherboard bundle (Biostar M7VIP) for $130.00 and give them a decent upgrade, but then they are in for $130 mobo/cpu, $65 for 20 gig drive, and $20 for 128MB RAM. That's $215 before shipping and my time. (somewhere around $265 - $285 total)

Grrr. I just wish I could say what is wrong for certain.

 

[RemyCanad]

I just thought of something. Make sure that wasn't already a known problem! I know alot of computers that user have had and when they bring it in I ask if there are any oddities with it. Some have problems like this. Where they have to turn the PSU off and on in the back before it comes on.. And apparently it had always been like that.

 

[compudog]

UPDATE:

I now know why the old hard drive was flaky. There is definately something wrong with this mobo. I put the new hard drive in and boot to the win98 floppy, do the fdisk/format/ md win98, copy cd/ etc etc. Start windows set-up. Good, it all works (still doesn't start without playing with the buttons...) Anyway, once I start loading the SiS drivers for the video and IDE things start going south. The hard drive gets corrupted, system will only boot into safe mode, says that there are possible bad sectors on HDD. Etc etc. I going to replace the mobo.

 

[RemyCanad]

So do you think that old HD is fine? And I wonder if this thing was ever hit with some type of electrical spike....

 

[compudog]

I have the old hard drive out and working in another computer. It's fine. The new hard drive is now fine as well. I am pulling out the old Asus board. I just spoke to the client and I ordered a Biostar M7VKQ board with a Duron 1.3 for $99.00. It is an integrated board, but should give them much better performance than what they had. This was just such a weird problem.