Chromatography Forum

Hi all,

I am trying to get an older Agilent 6890 with 6890 Series Injector autosampler and Controller up and running in our lab. Afer a couple of successful trial runs, I started getting an error message "Front plunger error." I have cleaned everything I can in the turret, replaced the syringe, and even tried running without the syringe installed, and still I get the error message.

The plunger carrier loop seems to slide pretty freely, but there is a plastic gray lever near the top that looks like it should move, but isn't doing anything (sorry I don't have the proper name for it, my manual is sorely lacking information!). Sometimes the autosampler will get started, try a couple washes, and get to the sample and then have the error--other times the error shows up on the first wash.

By the way, my "solvents" and "samples" are just empty vials at the moment while I try to get this thing working. No one in the lab knows if the autosampler has ever even been used (or they're not admitting to it!).

Thanks for any suggestions!

Dear Sue,

Remove front plunger and fix it again and again it gets fix, hopefully, it will be ok.

Thankds and regards
Akbar

Hi,
Try to do injections with liquid in the wash and sample vials so the friction decreases.
How old are your GC? It might be that your tower need service! Hope it helps.
/Csaba

Hi

I assume 7673 model ( although they are all much the same )

Usually the error is caused by the plunger motor failing or an issue with the solenoid that controls the syringe volume.
Best bet is to get it serviced / repaired / exchanged.

It is many years since I used an Agilent autosampler, so this may not be useful, but it is worth trying before you start speding money on replacements or servicing. There might be a zero position setting for the syringe or plunger in the autosampler control software setup ??. Another possibility is that the belt that drives the plunger up and down had developed a stiff or sticky spot while in storage, if you remove the belt and re-install it at a different position you might get the problem area into a place between the sprockets where it does not make any difference.

Good luck

Peter

Agree with Peter. Belt does develop flat spots when sitting idle for long periods of time. There are no zero position settings in the software, but check the autosampler configuration setup. Make sure it has the the syringe size you are using listed. If cleaning and reinstalling the belt and cleaning the gear on the motor doesn't solve the problem, it most likely is a bad motor. Good luck and please let us know what you find.

I was having intermittant plunger errors on my 7673. It would go down into a wash vial then just stop. I fixed the problem by swabbing all the poles, and belts with cotton swabs and methanol.

Okay. You get this message but does it make an injection? Even when it is operating perfectly
it will often show this message after you fix the plunger error. Sometimes you can 'reinitialize'
the injector by unplugging the cable from the GC momentarily allowing the autosampler to go
through it's initialization procecure.

Hi all,

Thank you for all of your excellent suggestions. I attempted all the fixes I could try myself (cleaning, repositioning belts, re-zeroing, checking the syringe, putting methanol in the wash bottles), to no avail. So I replaced the plunger motor on this old beast (a 7683, as it turns out), and it is working again.

Thank you again for taking the time to help!

sueannmarie,

Thank you again for taking the time to help!

And thank you for posting the resolution to your problem. Knowing the outcome may be useful for someone else with the same problem.