G1946D autotune fail vcap

We recently reactivated an old G1946D with ESI-source which had low signal intensity before shutdown. After Cleaning everything, the signal intensities while autotuning with ESI-mix where better, but while trying to tune vcap it fails at 1700-2000V with the error "no ions found". Using the default settings I get around 32nA CapCurr and 1.6uA ChamCurr. In manual tune mode, ion count (for the 622 m/z ion) drops to noise level at around 1500V. Vacuum seems ok with 1.2-1.5x10-5 torr.

I wonder what would be the best order of (recleaning/ replacing) parts and what would cause this symptom.

With kind regards, Martin

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