View Full Version : Re: motherboard

03-24-2002, 10:48 AM
Awhile back I posted a message about having problems replacing a motherboard. Now that I'm looking at the problem again I get the same results.

posted by novacain:

Any beep at POST?

Any other sounds (like the RAM counter)?

Remove all the components except the graphics card , processor and ONE mem stick. See if it will POST then. If it does add components.

Check the power supply is compatible. Some of the 486 had different power needs but I thought that was only the 486DX 4 100.

Remove the battery on the motherboard for a few minutes to reset it to the fail safe BIOS settings.

There are no beeps and have tried restting the bios settings. Is the RAM counter the looping sound at startup? If so, then there is the sound of the RAM counter.

Any other possible solutions?

03-24-2002, 10:40 PM
Should POST first. (Pre Operating System Test, I think.) Detects all hardware is present and working correctly. No beep, more than one beep, means did not pass the POST. Therefore a dud, or incorrectly installed (wrong hardware settings) component.

Yes, the looping sound should be the RAM. (Clicking or ticking.)

Any lights going on in the drives? ie on the floppy? Check the HD cables for reversed connections. (Ribbon cables have a coloured edge, this should be closest to pin 1 in both the MB and on the drive. In 99% of HDs, not floppies, this is the side nearest to the power connection. MB should have it noted next to the IDE connector.)

Make sure you have a master on the primary IDE (HD on IDE1 is set to master and remove all other drives.)

Have you changed the CPU?
If so have you changed the MB's jumpers from the map in the manual. Old MB do not auto adjust like current MB's.

Only way to go, if you have already reduced the PC to minimum components, is to test the individual components in a working PC to eliminate the dud.

Sentaku senshi
03-25-2002, 01:01 AM
Cheak the bios to make sure your ram is set to quick cheak, or something of that nature

03-25-2002, 01:14 AM
>>Cheak the bios to make sure your ram is set to quick cheak, or something of that nature

Hard to get to the BIOS if not POSTing.

Sentaku senshi
03-25-2002, 01:33 AM
>Hard to get to the BIOS if not POSTing.

You misunderstood me. Enter the BIOS by pressing what you need to, during the start up. And cheak for something like quick test, fast test. Ram cheak and make sure it is fast.

I stupidly set mine to normal, and when it cheaked the ram it just keeps counting.

03-25-2002, 01:55 AM
If the computer never gets to a prompt (as I understand). Never displays anything on screen. eg does not start.
Does nothing but make a few noises, it is not possible to access anything. How would disabling an error checking mechanism help?

Better to keep the RAM counter on full test if the mem stick is suspect. Low level checks will not find most RAM hardware faults. Fast / no error checking is only if you trust the stick and need a fast booting PC. Mine at home is always set to error checking (counts three times to 1/2Gb), hit escape to continue if I am in a hurry.

Very hard to look at the BIOS (Basic Input Output System on EPROM, I think you mean CMOS).

03-25-2002, 09:24 AM
Yes, novacain your understanding of the problem is correct.

There's no floppy light or even keyboard communication. The power and HD LEDs light up. As I stated in the beginning of this when I put in the old 486 motherboard it works, but then I replace it with the P133 and nothing works. Is it more likey the power supply or the motherbaord itself?

And I can't even get to the on-screen bios settings.

03-25-2002, 09:32 AM
If the old 486 works, then it's more likely to be the motherboard that's faulty. Any way you can test the Penty chip (in someone else's machine for example)?

Have you checked jumpers etc?

03-25-2002, 09:57 PM
Does the floppy work in the 486?

Seems strange that the HD gets a light but not the floppy (as the Pentium should be checking for a floppy first if set to defaults).
Try without the floppy or ensure you have the twist in the right spot.
Its not an evil Compac or HP that has a pin removed from the floppy or needs different power (some from the MB)?
As Rob said, check the Pentiums jumpers.
Pentiums may require a pair of IDENTICAL mem sticks (some boards were fussier than others).

P133 has FSB of 33Mhz and 4x multi.