Hello all,
We are running a GC/MS 5977A/7890B in our lab. Last week, after cleaning and reinstalling our Extract EI source, the system pumped down normally, but the GC gave a "Thermal Shutdown" message. Under status, it read "Thermal Aux 2 Open Sensor" and "Thermal Shutdown". The Thermal Aux 2 is our MSD transferline and the MassHunter software also showed "----" for the Transferline Temperature. I restarted the GC, and got the message "7890 power on with exceptions." After pressing the Aux Temp# button I got the message "No sensor for heater" under Thermal Auxiliary 2 (MSD). I vented the MS again, turned off the MS, GC and PC. I disconnected and reconnected the comm lines hoping (with no good reason) that a cable had been jiggled loose. When I turned everything back on, the conditions were the same.
The setpoints are correct in the software and on the GC, but the actual temperature is reading 0, and it is cool to the touch. I checked the IP addresses, which all look fine. I pinged the MS and the GC from the PC, and both were successful.
We have never had problems with this heater and no indications that it was failing. Does anyone have any suggestions? At this point, I am thinking that I probably need to replace the heater/sensor assembly, but I would love to hear other ideas.
Thank you!
