Power supply or Motherboard?

[john-warren]

My system had me thinking it was stuck in sleep mode. I reset the CMOS and fired it back up. The power comes on, but cuts right back off, or stays on with no posting at all. No memory count, no hard drive spin up. When I take the cable lose from the hard drive, it spins. I then took everything out but bare bones, CPU, Video and still no luck. Any ideas?

[Bovon]

Please post your system specs.

Mobo, cpu, psu watts ect.

Could be the psu or maybe the fan on the heatsink died or came unplugged from the mobo header. Some motherboards have to detect a working fan on the heatsink right away, or they will shut down...a safty feature to keep the cpu from frying.

[cadetstimpy]

Looks like your taking the right steps!

With just CPU and video is the power supply still connected to devices? If so, disconnect one at a time.

Did the switch on the back of the power supply get accidentally switched to 220 V?

Do you have another power supply to test with? (only hardware item left if only testing motherbard, CPU and video fails... other than it being a bad motherboard that is.)

[john-warren]

The Mobo is marked as SY-5SSM, (no tech specs for power supply or mobo)it is a socket 7, the CPU is an AMD K-6-2 450Mhz. This computer has no on/off switch on the power supply. The power switch connects directly to the mobo. The cpu fan is working properly. The computer simply acted like it went into sleep mode. After unsuccessful attempts to re-boot, I opened the case, reset mobo w/ jumper and went to bare bones (CPU, VIDEO, MEM) This system acts like a Compaq with the four second delay for shut down, sleep mode and such. This is why I am unsure if it is a mobo or powersupply issue.

[Timbob505]

Here is a link to Soyo's website , go to support, and you can find a link for manuals. The 5ssm is under the 586 section. The ATX spec is such that you must hold down the power button for 4-5 seconds in order to turn off the machine. To me this sounds more like a dead board, but today seems like a day to recommend re-seating your cpu. It seems like the thing to do. I don't know why really, just that it once worked for me. If you can check the volts coming out of the PS, you can tell if it is going out instead of the board. Also, you can try another PS to see if that will fix it.

Good luck, let us know how it turns out!

Timbob

[This message has been edited by Timbob505 (edited 08-30-2001).]

[john-warren]

That was very helpful! Still no luck, but it did raise the question of how ACPI instrutions might be the problem. Is this possible? Do the settings for ACPI go back to default settings when CMOS is cleared. If not then how can I get them to reset?

[Timbob505]

Clearing the cmos will set everything in the bios to defaults. If you can' even boot up, I don't think ACPI is doing anything that is keeping it from coming on correctly. Sounds more and more like something fried: cpu, mobo, bios. You may try and get a new bios chip from soyo, it is cheaper than a new cpu or mobo. Other than that, I'm up for giving the whole computer a good drop-kick! Well, maybe that's not the best idea.

One last shot, after you turn on the computer and it blankly sits there, push the reset button. This worked once for me, who knows, it may work again!

Good luck, keep trying, someone will know what to do!

Timbob

[john-warren]

Thanks everyone. Chalking this one up to a crapped out mobo. TimBob has convinced me to redo my home network without even trying. This site is a dream come true!