Hi-Vacuum Gauge is Off or Not Connected in Agilent 5975C MSD

[casseiopia]

I'm using mass hunter and connecting an Agilent 5975C MS to a 7890 GC and for the first time today, I'm getting that the hi-vacuum pressure gauge reading is either "off" or "N/C" (not connected). I've already power cycled through the instrument and the computer twice. I also turned it "on" in the mass hunter user interface but it's not working. The turbo pump is running at 100% and the side door is experiencing a vacuum and the instrument status is "ready."

Has anyone had this happen to them before and might know why or know what steps I should take? Last week, the system was able to produce a pressure reading so I'm not sure what's going on today.

[mburleson]

I'm using mass hunter and connecting an Agilent 5975C MS to a 7890 GC and for the first time today, I'm getting that the hi-vacuum pressure gauge reading is either "off" or "N/C" (not connected). I've already power cycled through the instrument and the computer twice. I also turned it "on" in the mass hunter user interface but it's not working. The turbo pump is running at 100% and the side door is experiencing a vacuum and the instrument status is "ready."

Has anyone had this happen to them before and might know why or know what steps I should take? Last week, the system was able to produce a pressure reading so I'm not sure what's going on today.

Our system recently did the exact same thing and is also a 5875C to a 7890. I've found the best solution to be to just replace the gauge. You could look on eBay to try and save some money because they aren't cheap.

[cjm]

We have a few MSDs with non-functional gauges. We replaced one once but it didn't last too long, and yes, they are expensive. We found that we don't absolutely need the gauge functional in order to run the system safely, you'll just need to take precautions when scanning after system maintenance to ensure vacuum is sufficient and air/water are tolerable.