Chromatography Forum

Our 6890 GC-FID is refusing to light and stay lit. After inspecting the jet (clean) and the detector stack (also clean) I cleaned them anyway by sonication in methanol and acetone. After drying and reassembly. I still get the same problem. At this point I decided maybe it might be the electrometer signal. I am using the default lit offset of 2.0 pA.

When I watch the lighting process I hear it light and see a signal (detector control button on front panel) of 0.1 - 0.4. I assume this is supposed to go up to 2.0 or more? So, I'm getting no signal and I get the failure to ignite error.

It seems to me that maybe I have a fault with the electrometer. Can anybody point me at a resource to help me determine the problem?

... I am using the default lit offset of 2.0 pA.
...

Change it to 0.1 and check if it was the problem.

From another thread...

An easy check for FID electronics : touch the FID chimney with a syringe needle , you must see a very high signal .

So, I am not seeing a signal when I do this.

... I am using the default lit offset of 2.0 pA.
...

Change it to 0.1 and check if it was the problem.

I tried it and it did not work. Will try again right now.

Its no go. I'm not even seeing 0.1 I do hear it lighting and then popping a second time when it turns off the gasses.

Flow control seems to be happy. I am going to try checking the electrometer spring contact with the chimney. Unlike the long spring of my 5890, this 6890 spring barely extends to touch the disk.

I shut down and turned off all the power to the instrument. I removed the electrometer package to visually inspect the PCB and finding nothing decided to stretch the spring an additional 3-4mm. Upon re assembly, I could feel it firmly contacting the rim of the detector. I buttoned everything up and restarted the instrument. Once the jet had lit, I had 20 pA showing. I am running a set of standards and samples tonight. But I think I have it licked.

Sometimes it is something simple ! Thanks for the update.

Peter

I've only run about ~1000 injections since I bought this detector brand new. It looked pristine when I disassembled it. It seems odd that the spring shrank away from the collector disk. I suppose it was stretched to assemble it and over time it retracted.

Our 6890 GC-FID is refusing to light and stay lit. After inspecting the jet (clean) and the detector stack (also clean) I cleaned them anyway by sonication in methanol and acetone. After drying and reassembly. I still get the same problem. At this point I decided maybe it might be the electrometer signal. I am using the default lit offset of 2.0 pA.

When I watch the lighting process I hear it light and see a signal (detector control button on front panel) of 0.1 - 0.4. I assume this is supposed to go up to 2.0 or more? So, I'm getting no signal and I get the failure to ignite error.

It seems to me that maybe I have a fault with the electrometer. Can anybody point me at a resource to help me determine the problem?

Do the following steps:

1. Verify that the body of the detector is properly adjusted.
2. Check the column connections to the detector for leaks.
3. Verify that the ignitor that is on the upper part lights up when the ignition order is given, if it is too deep, with a needle you gently bring it out a little.
4. On the gc board, locate the Front detector or back detector depending on where you have your detector and then position the cursor on H2 and press the ON button for about 2 minutes. Then turn on the detector as it turns on normally.

I think I'd reduce the lit offset to a lower value, like 0.4 and try that.

We had this issue on one or two of our 6890 units, and had to do this and save into all its methods.