FPD troubleshooting

[Earl]

I am new to FPD and am trying to do some troubleshooting. What could cause almost complete absense of peaks? What is the correct or recomended insertion distance of a capillary column into an HP5890 FPD? My manual recomends 155mm from the end of the column nut, is this correct? There is definitely column flow and the flows at the detector are at their recomended values: 100mL/min for air and 75mL/min for H2. I have tried increasing the amount of H2 gradually to the same as the air with no luck. I have confirmed that the injection is working by switching to the FID I also have installed on this GC. I believe I can detect the solvent on the injection, but my test mix is not showing up at all. Any thoughts?

[xxx]

Your parameters for FPD are good.
You say that you see all the peaks you need with FID,therefore the chromatography works...

Don't forget to light on your FPD!
Do you have the right Filter S or P for the right substance?

Tell us a little more about your method....

Bye

[Earl]

The FPD is definitely lit. I have the phosphorus filter in and am running organophosphate pesticides.

Can the filter be a problem? is that something I should need to clean? I just got this detector used, and it may need some more upkeep.