At Celerity we were porting Unix to a new NCR chipset for our washing machine sized Workstation. We had a VAX 750 as the development box and we cross compiled to the NCR box. We contracted out the 750 maintenance to a 3rd party and had no problems for a couple of years. Then one day I came in to work to find the VAX happy consuming power and doing nothing. Unix wasn’t running and nothing I could do would bring it back. After about 2 hours I got my boss and we contacted the maintenance company. They guy they sent did much what I’d done and then went around the back. He pushed on the backplane of the machine and Lo, it started working. He then removed the pressure and it failed quite immediately. Turns out the backplane had a broken trace in it. We had done no board swaps in many months and the room had had no A/C faults of any kind. The company got a new backplane and had it installed in 2 days. Being 3rd party we couldn’t get it replaced any quicker. After that it worked like a champ. Celerity eventually became part of Sun as Sun Supercomputer. David