Sometimes service visits go in a direction you couldn't have prepared for. This one was a great example of that.
It impossible to know when you will get the service repair from hell, but only years of experience and trust in your abilities will help you to not get rattled by it. It happens.
System: PerkinElmer Clarus GCMS (over 20 years old), Tekmar Purge &Trap (also very old(.
Initial issue: autosampler arm stalling
I had been on-site for other small issues the weeks prior, easily taking care of them and leaving the system up and running after I left. In this case, it took a couple days for the parts to arrive from Tekmar. Once you actually get in touch with the right person, Tekmar support is top notch.
While waiting for the part, the GCMS shut down due to a power outage. It was down over the weekend and the PMT (photomultiplier tube) absorbed helium which causes low response. As a result the system had to pump down and bake out for another couple days to recondition the PMT.
After all of this, the internal standard valve went bad, along with poor standard curve results (which we attributed to a dirty source. Valve ordered, delivered, and another week down... we cleaned the source and replaced the valve. I also replace the forward focusing chamber, moisture trap and analytical trap, along with sparge vessel (very dirty!).
At this point the system would need a full refurbishment to do any more for it. We let it sit running blanks, and replaced all IS with new. After about a week the system calmed down and is now running.
In this case, I have known the owner of the lab for years. He was very understanding. This isn't always the case. Some customers become irate, while others will quietly blacklist you from the site.
I hope this insight might help anyone that runs a lab in some way.