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soft reset after POST

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ramses

Thu Jan 03 2008, 06:08PM

Registered Member #1208 Joined: Thu Jan 03 2008, 05:30PM
Location: Chesterland, OH
Posts: 154

well i took an old computer apart (200mhz processor), to see if i could get a bigger hard drive to work in it(it had a 1.5gb HDD in it. not a typo 1500mb). it ended up being a pain to get out. i ended up taking the cd drive out, the power away from the MOBO, and everything like that. after plugging everything back in, it gave me a RAM error (beeps) i cleaned them with an eraser, and put it back in. then it was a video error and i did the same thing. that didn't work, so i started stripping it down. HDD, CD rom, sound+network cards. then it tried to boot and couldn't, so i put in my windows ME boot floppy, and it booted from that. i tried again, and it wouldn't try to boot!. after a few times i got a video error, so I cleaned that again. I got it to try to boot again after everything was removed besides vid. card, CPU and RAM. I tried again, and it didn't work. i checked the MOBO for split caps, and to see if it was shorted against the case. another weird thing: when it resets, the CPU fan keeps spinning, and the voltage on the HDD power connector stays on. i read that it could be the reset switch, so i unplugged that and it didn't help. the weird thing is that it worked before i messed with it. no components were changed. I WOULD just zap it with the 2.9kv cap bank i have coming, but my dad doesn't want me taking apart a descent computer because i broke that one. 400 mhz ram is kinda slow, isn't it? thanks in advance.

Andrew H

Thu Jan 03 2008, 07:37PM

Registered Member #1198 Joined: Sat Dec 29 2007, 05:39AM
Location: Seattle, WA
Posts: 21

Most MoBos have a jumper to reset the CMOS to factory default. If that doesn't work you may have to wipe the HDD and reinstall from scratch. To get it to boot try stripping it down to the bare bones (ram, HDD and CPU, use the onboard video if your MoBo has it) and booting.

You might also want to try using canned air to blow any dust out of the MoBo connectors. It's possible that some dust got in there and is causing a short.

One final problem might be the PSU. If the PSU is failing computers respond in all sorts of creative ways. If you have a spare PSU try that out.

ramses

Thu Jan 03 2008, 09:18PM

Registered Member #1208 Joined: Thu Jan 03 2008, 05:30PM
Location: Chesterland, OH
Posts: 154

i tried booting it with just the cpu, ram and vid. card. (no onboard video) the MOBO power is 2 6 pin connectors and i dont have any old PSU's that i know of. the thing that bugs me it that it worked before I took it apart, and now it doesn't. what exactly would have failded in the PSU so suddenly. another possible problem is that after it wouldn't boot, i switched the 2 6 pin power connectors to the motherboard, but I have had it successfully "try to boot" after that incident. thanks for the tip about the dust. I never thought dead skin cells were conductive!

EDIT: is DDR2 ram still hard to insert like SDRAM?

Bjørn

Fri Jan 04 2008, 03:05AM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

Old computers can fail suddenly like that. Some times they have broken conductors on the PCB and any stress on the PCB will make it fail completely or behave erratically. If the problem seems to change it is usually a sign that it will never recover.

If it is the connectors corroding then spraying something like CRC 5-56

on all connectors can help a lot.

On my new computer the DDR2 modules were reasonably easy to insert, not like the old SD-RAM ones that left imprints on your thumbs for a day.

Electroholic

Fri Jan 04 2008, 03:08AM

Registered Member #191 Joined: Fri Feb 17 2006, 02:01AM
Location: Esbjerg Denmark
Posts: 720

Try taking the mobo out of the tower and boot it outside, sometimes if you tighten the screws too much, it will give you trouble.

as for DDR2 rams, they are still cardedge style.

ramses

Fri Jan 04 2008, 01:58PM

Registered Member #1208 Joined: Thu Jan 03 2008, 05:30PM
Location: Chesterland, OH
Posts: 154

thanks! do you think pushing the ram into the MOBO broke something. I heard that when the xbox 360 overheated it bowed the MOBO and de-soldered itself. I was bending the MOBO a lot to stick the RAM in there. I ended up getting on top of it and pushing down. would WD 40 work instead of the CRC 5-56? If none of that works, where should i fry it with the 2.9kj cap bank?

Bjørn

Fri Jan 04 2008, 03:22PM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

WD-40 should do the trick just as well. I have never broken a new motherboard even when using excessive force but I have had some old ones fail by just flexig them by a tiny amount. My theory is that it is hairline cracks in the PCB since it seems to depend on force and temperature and it is impossible to get them stable again. When they get to that stage they generally get worse until they fail completely. They also have an annoying habit to improve when you tinker with something unrelated and soon develop even worse problems.

Fry it outside and wear protective goggles.

ramses

Fri Jan 04 2008, 03:31PM

Registered Member #1208 Joined: Thu Jan 03 2008, 05:30PM
Location: Chesterland, OH
Posts: 154

thanks! if i do fry it, where should i hook up the leads? i'm thinking the power to the MOBO, but for maximum effect is there any place that would be better? Maybe i can use the case to house the charger or something.

Wolfram

Fri Jan 04 2008, 06:33PM

Registered Member #33 Joined: Sat Feb 04 2006, 01:31PM
Location: Norway
Posts: 971

Between the 5V input and ground should be good.

ramses

Fri Jan 04 2008, 06:59PM

Registered Member #1208 Joined: Thu Jan 03 2008, 05:30PM
Location: Chesterland, OH
Posts: 154

i took the MOBO out of the tray, dusted it off, took off the fan + heatsink/ dusted them off. there was crap between the heatsink and CPU, so i wiped both surfaces with rubbing alcohol. (no thermal compound). put it all together and now it won't even beep, or turn on the energy star monitor. to the 2.9kj cap bank! ;(

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