Bizzare Boot Issue

OK techies, I need some help:

I'm building a computer out of spare parts. I cleared the CMOS on the MoBo and it booted up fine... detected the CPU correctly, RAM, video, etc.. However, when I "Save and Exit" the BIOS, the computer reboots and hangs with no POST... blinking monitor light but all fans/drives running. I can clear the CMOS again and computer boots fine until I exit the BIOS again and then it hangs. It even does this when I don't make any changes! Every time, it can only boot after a fresh CMOS clear.

I have tried changing PSU, CPU, RAM, Video Card and CMOS battery... no joy.

Any suggestions/help?

Specs:
Abit KT7 Mobo
Athlon 1200 CPU
768MB PC133 RAM
TNT2 Ultra 32MB Video Card
10/100 Ethernet card
Soundblaster AWE64 ISA
350W Switching PSU
Sony DVD-ROM
3.5" Floppy
Fujitsu 20GB IDE HDD

Thanks...

 

Since you've swapped out everything, and tried a new CMOS battery, I'd say the motherboard is faulty. You could try booting without the floppy connected, and/or without the optical drives connected, and maybe try a different hard drive.... but I still think it's the motherboard, but I have seen bad floppy drives cause similar symptoms. Try booting with ALL the extras removed; pull the sound card, ethernet card, modem, etc...

 

Are you certain you have the (Clear CMOS) jumper on the correct pins for Normal operation?
(Pins 1 & 2 jumpered for Normal. Pins 2 & 3 jumpered to Clear.)
Pin 1 is closest to the CMOS battery.

 

Thanks for the replies.

Yes, I cleared the CMOS correctly, unplugged, removed battery and changed jumper. The settings are reset to default when it boots again so I know it's working.

I'll double-check the pin settings and try without stuff connected and let you know.

 

You said in your last post that you ''removed battery and changed jumper'' is that what you actually did, as I assume if battery taken out there is no power on your mobo to reset when you change the Jumper settings. If that is the case leave the battery in and just change/reset the CMOS.

 

I'm not sure I follow what your suggesting... removing the battery and changing the "Clear CMOS" jumper does reset the BIOS to default... which is what I have to do to get a boot... but it won't reboot afterward even if I make no changes to the BIOS.

 

Lets start again .. Your CMOS Jumper has 3 pins .. pin 1 & 2 for normal run mode.. putting Jumper onto Pins 2 & 3 for 10 or 20 seconds will clear your settings and revert back to factory settings. Replace the Jumper back to pin 1 & 2 and boot. This is done with the Battery NOT taken out.

 

Sorry, I understand what your saying, I know how to clear my CMOS, and I have, but that only seems to allow one boot.

Also, AFAIK taking the battery out (with the power disconnected) for 2-3min+ resets the CMOS on most MoBos... at least in my 24+ years of computer experience

Anyway, I appreciate the help... I think it must be a hardware issue so I will be stripping it out and building piece by piece this weekend.

 

Got that cleared up .. lol reading your symptons again .. check wiring connections to HD and ROM. are they tight, just one slack wire connector from the 4 can cause this prob, and if you have extensions check those as well. I've had similar with these faults and have swapped connectors till I find one that is really tight..... best of luck at the weekend.

 

Good idea. Be sure to boot up between each device as this will help you determine where the problem lies. I'm thinking about this, and since you can only get a boot immediately after clearing the BIOS, I'd say the BIOS may be corrupt. Download the newest available BIOS from the motherboard maker's web site and flash it. If you can't successfully boot even with all the devices removed, then it's most definitely the BIOS or the motherboard.

 

Thanks again for the help, guys

 

Well, I couldn't lock it down so I tried a differnet MoBo/CPU combo with the same RAM, video etc., and all works fine now. Strange since I had the other MoBo/CPU running fine no that long ago.

Thanks for all the help though.