The two most common failures in the 7100 are dried out heat sink grease and cracked CPU chips. So, if you have not already, pull the heat sink (carefully, gently, don't cause number 2) and clean off the old dried powdery heat sink compound. If it isn't old, dried and powdery, then someone did some maintenance at some point.
Check the CPU for cracks in the plastic around the metal die in the center. Then, if not cracked, apply new heat sink grease. Just use a small dab. It is only meant to fill the imperfections between the flat mated surfaces. If it runs off onto the pins it can cause shorts and damage your logic board. The grease only goes on the metal die, not the surrounding plastic.
It is possible that your CPU IS overheating as soon as it finishes POST although it seems unlikely. Next most likely is probably bad RAM, although I think a badly cofigured SCSI bus can also cause this. Have you tried booting with all cables except power and speaker disconnected and all RAM and cache removed?
Oh, and PDS termination. The PDS slot must be terminated. If there is not a video card in the slot it needs a PDS termination card.
Check the CPU for cracks in the plastic around the metal die in the center. Then, if not cracked, apply new heat sink grease. Just use a small dab. It is only meant to fill the imperfections between the flat mated surfaces. If it runs off onto the pins it can cause shorts and damage your logic board. The grease only goes on the metal die, not the surrounding plastic.
It is possible that your CPU IS overheating as soon as it finishes POST although it seems unlikely. Next most likely is probably bad RAM, although I think a badly cofigured SCSI bus can also cause this. Have you tried booting with all cables except power and speaker disconnected and all RAM and cache removed?
Oh, and PDS termination. The PDS slot must be terminated. If there is not a video card in the slot it needs a PDS termination card.