5890 FID - no signal

[adamdhughes]

Hi
I am wondering if anyone can help. I am trying to bring up a 5890 FID. However the only value I get from the detector signal is 830000. This never varies no matter what I do to the gas mix etc. Can anyone tell me why I am not getting a more sensible reading from the FID and what I can I do about it? I have gone through the manual several times and found nothing helpful.

Many thanks
Adam

[Suresh Seethapathy]

Hello Adam,

Looks like somebody has come up with this query earlier as well. You might want to check it out. Just use search with "830000" as the key word and you will get to that thread from there.

Good luck
Suresh.

[adamdhughes]

Hi Suresh,

Thanks for pointing this out, I had search the forum before posting but didnt use the 830000 term. As soon as the GC cools down I will try some of the suggestions.

Thanks for the input
Adam

[GasMan]

Adam,

The number 830000 signifies that you have a direct short to ground to the FID electrometer input. It has nothing to do with the gas flows. The electrometer is the board mounted on the right side of the 5890. It is connected to the FID body via a probe with a spring on the end. This spring should ONLY be in contact with the collector assembly. It is possible that the spring is touching some other part of the detector that is grounded.

If you disassemble the FID when it is cool, you should see the problem.

Gasman

[adamdhughes]

Thanks Gasman,
When I took the detector apart I could see that the spring probe had been damaged and elongated and so was shorting. I now get a nice zero reading which again does not seem to fluctuate, whether the gas is on off or the detector lit or unlit. If you have any further pearls of wisdom to cast I would be truely gratful.

Adam

[Consumer Products Guy]

If you have any further pearls of wisdom to cast I would be truely grateful.Adam

Yes, I've also had that reading, agree that it's a short. Another pearl: if the ignitor doesn't glow when gases are OK and button is pushed, use 5/16 inch wrench to loosen the ignitor a little, then retighten it. Then loosen, the retighten the Posidrive screws for the detector mounts. Oftentimes this restores electrical contact and the ignitor will then work. And screwing in a new one also restores the connection, so many think the original ignitor was bad.

[Russ]

Another "trick" with the ignitor is to run a ground line (you can attach it to one of the mounting screws for the metal "tray" where the inlets and detectors are installed) and touch the ground line to the ignitor when pressing the ignite button.

[adamdhughes]

Thanks for the tips, as you may have guessed I am fairly new to this am trying to get a 5890 up and running. I now have the FID lit, and the detector reading. I am suffering from a noisey baseline and a lack of reproducability in the test solution I am injecting (C14-16 hydrocarbons). All tips and hints will be morre than welcome.

Cheers