This machine will work fine for about a day then usually will have a C-630 when we come in in the morning. The thermistor has been replaced for this problem without effect. The main and engine pcb were replaced last year for a different problem. I guess the next logical step would be to replace the power supply pcb. Has anybody seen anything like this? Thanks.

Find out if building temp goes way down at night. May take machine too long to warm up and pop code if starting at a very low temp.
copierdude

Thanks for the reply on that copierdude. The machine is in our shop now which is always warm(sometimes too warm) and it came from a hospital that is always heated. I checked the exaust fan operation too althoughI don't think I checked if it's changing from high to low speed at the proper times. Guess I'll check that. Thanks again.