H2 FID Trouble for HP-4890d

I have a problem with my FID on a HP-4890d Gas Cromatograph.

The FID was working as normal, then the FID didn't start, so I checked the gas flows, and the H2 didn't come out from FID. 

I suspect maybe the Hydrogen pipe line is clogged or the on/off valve is stucked 

Hydrogen use for the GC has a 99.998% purity and doesn't have a Moisture & Oxygen trap

Hydrogen reaches one side of the on/off valve but does not exit the other, also I suspect that the pipe line from on/off valve is clogged

I'm looking for suggestions to solve this problem

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