Boot Problems

[recce101]

One of my PCs is having boot problems. It's been fine for a year, then a month ago started to hang after turning on the power switch. The power supply fan and CPU fan start, power light on, some initial activity for maybe 3 seconds, then just sits there with fans running and power light on. Never gets to the point where the beep normally occurs, or where any video display begins. Never reaches BIOS setup screen or attempts disk access. Power off and back on a few times, and it will eventually catch and start normally with no error messages. All components work fine. Turn it off and back on within a minute or so, starts normally. But wait a few minutes before turning it back on and the same thing happens. Problem has gotten worse over the past month, and now to get it running after being off for a while takes many on-off attempts or, alternatively, leaving it in the initial hang-up mode "warming up" for maybe 10 minutes, then turning it off and back on, and then it will beep and boot up okay. Right now I'm just leaving it on with the monitor on power-save.

CONFIGURATION: Soyo SY-7SBB motherboard (Award BIOS) and 466 Celeron CPU in an AT case with 250W power supply, 64MB SDRAM, 10GB 720RPM Maxtor hard drive, CD-ROM, 3.5 floppy, internal 100MB ZIP drive, 3Com EtherLink III ISA NIC, Sony HMD-A100 monitor.

TRIED SO FAR: Tried different AC outlet/surge protector and power cord (though normal outlet checks at 119V) -- no help. Checked BIOS setup; confirmed it was still set on defaults as set a year ago; disabled fast boot option (due to previous experience with disk access problems with 720RPM drive in another system, though this one hangs before reaching the point where disk access is attempted); but no help and returned settings to default. Unplugged monitor power cord from back of computer and connected it directly to surge protector -- no help. Replaced power supply and switch with another 250W unit -- no help (output checks at 12 and 5 VDC within 1/10 volt). Unplugged monitor data cable from VGA connector, unplugged printer from parallel connector, removed unused modem card, removed sound card, removed EtherLink card, checked security of DIMM and all accessible connections -- no help. Replaced video card (4MB PCI) with 32MB AGP card -- no help. Replaced coin-style battery (although original one checked very close to the rated 3.0 volts) -- no help.

I have NOT replaced or disabled any of the drives, though I did check their connectors for security when replacing the power supply. Also, I have NOT replaced the motherboard. If it came to that I would probably get another type and move to an ATX style case anyway. If there's anything I can try short of replacing the motherboard, I'd certainly appreciate hearing it. Thank you in advance!

Ned

[glc]

Pull all the cards except the video card and disconnect all drives - see what happens and go from there. If it still wont boot, pull the mobo and try it on the table.

[recce101]

I'll try that tonight. Thanks for your quick reply. --Ned

[MadMax]

That's a tough one.
Might try re-seating the CPU, or replacing the CPU fan. Maybe it's not always running at full speed.
Could swap out the CPU but, to me, they either work or they don't.
It's not looking good for the motherboard.

[THE TV MAN]

that's a typical symptom of a dry capacitor.since you already replaced the power supply i would say you probably have a bad cap on your motherboard.try using a hair dryer to heat up the board after it's been off for a long time and see if it starts up then and that would confirm it.hope this helps.

[recce101]

TV Man:

Interesting! This makes sense, considering the fact that it starts normally after a "warm up" period. I haven't tried the hairdryer routine yet since the computer is still on and we need to use it first thing in the morning. So a couple of questions, please. I assume replacing a capacitor on a motherboard is not something your typical garage mechanic should attempt, that replacing the board is the best option? Also, if I confirm that's the problem, is it likely we could continue to use the computer as is with a warm up of some form on each start, or is it likely to deteriorate further and become totally unstartable in a few days or weeks? Thanks for your help!

Ned

[THE TV MAN]

you can probably use it for a while longer(maybe weeks or a month or two)but it will eventually dry up enough where it will stop working all together.it is not hard to replace them but you have to be very careful in this case because it is easy to damage traces on the board because they are so small.you will have to know which one is bad though.i would guess it's one of the ones around the cpu.you would need an esr meter to find the bad one so you might want to take it to a reputable electronics repair shop and ask them to find it for you.it should not cost you to much.you could also buy some freeze mist and spray one capacitor at a time until it shuts down and then you would find your bad guy.hope this helps.

[recce101]

Thanks, everybody. I'll just leave it running till I have time to pursue these suggestions, maybe this weekend. I'll post a follow-up after that. Meantime, anyone else with ideas or similar experiences, feel free to join in!