Hello,

I encountered a problem with the hivac system on a MS (5977B) after performing maintenance. The following maintenance was performed:
• New column installed- baked out at 5C/min until final temp of 325C (column's max temp)
○ No leaks observed, pressure holding at various setpoints
• Extractor source cleaned, two new filaments installed
• Ion chamber o-ring inspected and no signs of wear or contamination observed
• Rough pump oil changed- verified hose assembly was seated correctly and tight

One thing to note during the venting process. This particular MS has the rough pump hard wired, meaning that powering off the MS will not power off the rough pump. I completed the vent cycle successfully. Upon venting and powering off the MS, I opened the vent valve before realizing that the rough pump was still on. I estimate that the rough pump was on for approximately 2 minutes before I realized this and powered off the rough pump. So air was being pulled through the vent valve into the MS. While I was concerned about this mistake, I proceeded with the maintenance items mentioned above.

After completing the maintenance, I attempted to pump down the MS. I powered on the MS and the rough pump. The vacuum was verified to be intact, as the side panel sealed in place and the vent valve was closed. Upon reconnecting to the MS, the turbo pump's status was ON but the speed stayed at 0% with the error message at the bottom that "HIVAC NOT READY". I proceeded to troubleshoot this issue with the following:
• Vented and reseated the side panel numerous times- achieved vacuum every time
• Replaced the o-ring on the vent valve
• Verified that the transfer line side ferrule/nut were installed correctly and tightened
• Vented and installed a different rough pump- vacuum achieved

Any ideas on what could be causing the turbo pump to not start?

Thanks in advance,
Jim