Chromatography Forum

I may be moving on from my current position, leaving everything in the hands of some users who haven't got much of a chance to do maintenance on our instruments. Not that I haven't shared the opportunity when I could: it's just that we don't have to do it frequently and with turnover and schedule changes, nobody gets to do it repetitively. We'll have some time to catch up if it comes to that.

My question for you all, is whether the supplies that are supposed to make it easier to do basic things like inlet maintenance are worth it. We have 6890s with 5973s, FIDs, ECDs.

I'm talking about things like Agilent column instillation tool, finger-tight column nuts, etc. Other suggestions are welcome, though.

I stocked maintenance and some repair parts, and I was able to do pretty good troubleshooting, which made repair easier (Agilent GCs, HPLCs, GCMS units).

One time I drilled a hole in the long plastic rod for the 5890 GC on-off switch and corresponding broken plastic tab on the circuit board, and used a bread bag tie to secure the rod in the tab on the circuit board, so a brand-new circuit board wasn't necessary.

One time a 5890 round oven-vent cover broke free from the motor-actuated rod; I went home at lunch time and fixed that by installing a couple of rivets.

I stocked maintenance and some repair parts, and I was able to do pretty good troubleshooting, which made repair easier (Agilent GCs, HPLCs, GCMS units).

One time I drilled a hole in the long plastic rod for the 5890 GC on-off switch and corresponding broken plastic tab on the circuit board, and used a bread bag tie to secure the rod in the tab on the circuit board, so a brand-new circuit board wasn't necessary.

One time a 5890 round oven-vent cover broke free from the motor-actuated rod; I went home at lunch time and fixed that by installing a couple of rivets.

Pretty sure Agilent doesn't sell random garbage that's been accumulating in a lab.

If you run clean matrices Merlin microseals have been nice for extending calibration lifetimes and reducing overall endrin breakdown. I've had calibrations last for years without touching the inlet on some ECDs. If you don't need a guard column a restek inlet (27184) lets you run a double hole ferrule and jam both columns in the inlet if you run something like a recessed gooseneck liner, not a fan of the glass y-connectors and Agilent's UltiMetal splitter tailed for me.

We have a pile of finger tight and self tightening nuts but they aren't installed on anything, people that have been here longer said they leaked over time.

Electronic leak detector if you don't have one already, it pays for itself.

We have a pile of finger tight and self tightening nuts but they aren't installed on anything, people that have been here longer said they leaked over time.

We had about 5 GC systems and 3 GCMS systems, and we used finger tight nuts on some of them, and did not experience issues with them.

One time a 5890 round oven-vent cover broke free from the motor-actuated rod; I went home at lunch time and fixed that by installing a couple of rivets.

I've rebuilt a few of those. For a while I seemed to have a rash of flappers going bad in various ways, and just started swapping them as needed and rebuilding as I had the time(although IIRC-it's been a few years since I've messed with one) the 5890 flapper motor goes into an 8 or so pin Molex-type plug and you need a pin extractor to pull it loose.

The flaps themselves always made me happy at least as fixes go. I got to where, once I had the assembly out, I could do one in ~10 minutes by just drilling out the arm, flap, and the metal backing plate(and anything else in the "sandwich" if I've forgotten something) and pop riveting it all back together. I never had a repair one fail, and I started proactively just doing both after once or twice of one of the flaps failing and then the other going a few weeks later.

I still have one or two with a faulty coupling between the motor and the arm. They could probably be fixed-I forget the exact mode of failure but know that basically the arm swings free from the flap. I'd thought of cross drilling and pinning, especially as the motor itself still worked, but never had the need to go that route as I still have a few good ones salvaged from 5890s we ended up parting/junking out.

I'm pretty sure the oven flapper was the only mechanical part I've ever actually had issues with on the 5890. I have a couple of oven fan motors and other odds and ends I've saved, but don't recall ever having to replace one...on the whole HP built a pretty darn good basic chassis in the 5890, and I guess the fact that even the 8890 feels very familiar to someone who has worked inside a 5890 shows that.

Something that definitely helps the "occasional maintainer" is to have all the parts properly labelled. If you've got a drawer full of ferrules, it's worth marking which are for the inlet end of the column, and which at the detector end. If you've got accumulated 5 packs of weird liners for special purposes but usually use one standard type, it's helpful for users to know which is the inlet liner they should be using. Same with septa if you've got a couple of different varieties floating around.

... and good luck with your new post! Hope all goes well!