T40 Shutdown with mobile 7500 instability

[john giddings]

I have a T40 laptop that frequently shuts down. It seems as if it is still running but without any video. It doesn't work with an external monitor. The time it stays on varies from almost nothing to a couple of hours. It does it whether the hard drive is in or not. I contacted IBM and was told by one technician that I should replace the inverter. I did this but the problem persisted.When it turns on after a shutdown there is an error message saying that there is instability with the mobile 7500 device. The error signature has a number of entries. I downloaded the latest video drivers but this did not help either. Is there anything other than replacing the motherboard that can be done.

John Giddings