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TCD no peaks after extended shutdown of GC

Question asked by tak on Sep 16, 2020
Latest reply on Sep 16, 2020 by tak
Hello Agilent Community,
We shut down our 7890B GC (G3440B) a few months ago and I just turned it back on. First, I had to re-assign the license and re-establish the network connection for some reason, but I was able to re-connect the GC to the PC (this is probably not related to the following issue but wanted to mention it).
Unfortunately, now the TCD does not show any peaks when I run the GC with our previous methods.
I can see the baseline at the expected value, but no peaks appear.
When I change the reference flow, I can see a shift of the TCD baseline.
I can hear the TCD clicking and the valves injecting my samples.
My sample gas flow in front of and behind the GC is the same, so I would not expect a leak.
Baking (oven temperature at 225 C) did not change anything.
Do you know what could be causing this?
I would appreciate any advice.
Thank you!

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