Welcome to our community

Folks,

Got a 4100 here running with 3 CPUs and 3 PSUs quite happily, has done for years. Recently we tried to add a 4th CPU and the system won't POST, it reports fan failures on either CPU1 or CPU3.

All fans are spinning and the error's consistent even if CPU0 and CPU2 are swapped to the other locations. Since no power errors are logged we're suspecting the slot for CPU3 has failed, but has anyone else seen this before we start gutting the machine?

cheers

Hello Witchy,
Sorry for the delay, hols and all that. I presume that this fan problem is isolated to slot 3 regardless of which CPU is installed? If this is the case, and the fan is actually spinning, it is possible that the Power Control Module(PCM) is the cause. It may not be detecting tach pulses from the CPU in slot 3. In any case this module is easier to replace than the Motherboard. If the PCM doesn't fix the problem then it is likely to be the Motherboard.

Have had to replace a motherboard on one of these in the past, make sure you put aside a few hours for head scratching
Have you checked the led's on the pcm for the fans or did you get the info from the lcd panel?

If you need the service manual let me know your e-mail and i'll send it to you (1.73mb)

Hi Pauls,

Hols here too

The fan problem seems to go randomly between CPU1 and CPU3 only when a 4th CPU is installed; the lights on the PCM will halt at whichever CPU is reporting the problem, normally they'll cycle as expected.

Add a 4th CPU and it's game over.

I've swapped plenty of these motherboards in the past so no problem there