6890N ALS issues

[bakej0]

We have an Agilent 6890N with a 7683 ALS. We keep getting injector tower faults. Agilent keep sending out replacement towers which temporarily fixes the problem. We are currently on our third tower. I have a feeling that it may be a firmware issue. Has anyone else had similar problems?

[gcguy]

What is the software describing the fault as? How many flashes are you getting from the fault light?

[bakej0]

We get four flashes from the fault light which is described as a plunger error. We have replaced needles and injection port septa but this does not help.

[gcguy]

With out wanting to sound like I am suggesting the obvious.....

When you got your towers replaced on the exchange programme did you put in a new syringe? Are you using the correct type of syringes. Is the sample you are injecting causing the problem, is it viscous or sticky? Do you have enough solvent in the flush bottles.

If you have had the towers replaced I can't really think of anything else, these errors can be caused by allingment issues but if you have had the tower replaced this should not be a problem.
What do Agilent say?

[bakej0]

We are using the Agilent Gold standard syringes and we have taken new syringes out of the packet and the fault persisted. We are not injecting sticky or viscous samples.

Agilent don't know what the problem is but agree that it could possibly be a firmware issue. They have previously reported an issue where the firmware for their autosampler tray became corrupted over a period of time.

[skunked_once]

I have been frustrated more than once with the same problem. A good way to test if the syringe is the problem is to remove the syringe from the tower and then start a sample. In my experience, the autosampler cycles without the syringe in place. If this is the case, thoroughly clean the syringe and try again. You may have to try 2 or 3 syringes to find one that works. These autosamplers seem to be very sensitive to this.
Good luck!

[bakej0]

I have been frustrated more than once with the same problem. A good way to test if the syringe is the problem is to remove the syringe from the tower and then start a sample. In my experience, the autosampler cycles without the syringe in place. If this is the case, thoroughly clean the syringe and try again. You may have to try 2 or 3 syringes to find one that works. These autosamplers seem to be very sensitive to this.
Good luck!

Have you had these problems with brand new syringes straight out the packet? Wouldn't this suggest that there is a problem with the drive mechanism?

[skunked_once]

bakej0,

I have not noticed whether the error occurs with brand new syringes. What I have seen is that the error can occur even though the syringe feels clean and is not sticky. What really puzzles me is that the error sometimes occurs at a time in the cycle where the syringe is not penetrating the sampe vial or being rinsed. There is nothing happening with the syringe itself but the autosampler will register the injector error and stop. If I remove the syringe, the process occurs without a problem. I can't explain why this occurs but the only remedy I have found is to reclean my syringes or try a new one until I find one that works. I have not tested the affect of phase-of-the-moon, sunspots, or stray electromagnetic effects on the possible cause of this error. Any and all explanations from others are welcome.

[bakej0]

We have taken brand new syringes out of the packet and the problem has persisted. I have not tried to run without a syringe as yet. It may be that there is a problem with the sensor that detects the resistance of the syringe. If this is too sensitive then even good (or brand new!) syringes could cause errors. This could possibly be linked to the firmware.

[gcguy]

With the Agilent tower there is a small arm "the vial stripper" which is tensioned by a spring. If dust and fluff clog the spring then it can stick intermitantly. If you move the carousel away from it but turning it, make sure that the arm is free to move, if not give it a clean. I would not recommend using oil as this can attract dust, try a ptfe lubricating spray.
If this arm is sticky then it can cause errors in fuuny places.

GCguy