From: utzoo!decvax!harpo!ihnss!ihps3!stolaf!minn-ua!chris Newsgroups: net.bugs.4bsd Title: Re: 11/780 crash Article-I.D.: minn-ua.190 Posted: Thu Jun 10 01:13:52 1982 Received: Fri Jun 11 01:18:26 1982 We just finished with a severe case of the INT-STK NOT VALID's. In our case it turned out to be a bad System Industries MBA backplane. The problem developed after 6 months of use and was supposedly due to a bad solder joint on a power pin. The CE had to swap the entire CPU to isolate the problem. Prehaps your problem is similar? Good luck. Chris Boylan University of Minnesota Computer Center decvax!pur-ee!minn-ua!chris