Chromatography Forum

Hi all, i have an issue that i could do with some advice for. I have an Agilent 7890 GC-FID that was giving a strange high voltage error after one of my analysts took apart the FID for cleaning.

He may or may not have dismantled the electrometer aswell. I'm wondering whether something has died, which is preventing the bios from booting. It hangs during its boot sequence, the lights on the front panel go out and nothing else happens. The software cant even recognise the instrument either.

Hoping someone can advise or its getting a viking burial with the analyst stuffed inside it!

Have you tried removing the electrometer and booting the instrument? I haven't worked with the 7890s except when attached to a MS, but maybe if the board in the electrometer is bad, the instrument will boot without it? If it does, then you know where the problem is.

Hi;

I had something similar happen a couple of years ago to my Agilent 7890A, except all the lights were on simultaneously and nothing but erratic characters on the screen. Rebooting didn't help at all.

It did resolve itself, after I powered it down, blew the dust off the Main board & CPU, and reseated all the cables. Did you get your analyst to reseat the spring to the collector in the FID?

Anyhow, maybe we were just lucky, but after doing that, it came to life and has worked fine for two years.

Not much help I know, but worth a try. Good luck.

I'll disconnect the electrometer and see if it boots. Following that i'll try reseating all the cables and see if that makes any difference. otherwise its an engineer call out i think.

Thanks for the suggestions all!

Hello

I think that you have problem with spring that is in FID detector.
Collector has groove and spring should be there (in your case it is probably not there and touching base of FID). You need to use flat screwdriver to make sure that spring is in the groove.

Regards

Tomasz Kubowicz

We did replace the spring. However we did check to make sure there was contact. We were thinking that noisy chromatograms were being caused by poor contact in the spring. I wonder if something got damaged during the maintenance.

I'll try reseating the spring though and see if that makes a difference.

The spring doesn't have anything to do with it. If the spring isn't making contact you just won't have signal, and if the spring is shorted to the FID body you'll get a signal up around 8.3 million. I agree that you should first power off instrument, unplug the electrometer from the signal board and boot back up. Those boards and electrometers do not frequently fail this way but it can happen (if the analyst opened the electrometer box I'm not surprised.)