Problems of Tuning action stopped, GC/MS is just noise

Which voltage test point?    The sideboard is permanently damaged if the cables are connected to it while the power is on.  Did that happen?

Notice in your picture above that the HED is set to On.

If the HED power supply is not functioning properly and providing -10,000 V through the thick white wire to the connector at the back of the analyzer, then there will be no peaks. BUT, you may be able to see peaks if you increase the EM Volts. At the very least increasing the EM Volts should change the size of the background/noise peaks that are seen in your screen capture.   Try increasing the EM Volts, 2200...peaks? 2400...peaks?  2600...peaks?  If increasing the EM Volts gives peaks, then the best guess is that the HED power supply has failed, and not the side board.   If increasing the EM Volts increases the background/noise peaks, that tells you that the electron multiplier and signal processing circuits are working, at least.

Hi how are you, I was gathering information. We had another visit from a technician for a second opinion and this was his report:

Diagnosis: The Mass Detector is not able to perform the AutoTune and the Manual Tune, it has no response only background noise, so it is believed that the Side Board is damaged, diagnostics were made which shows a problem of abnormal voltage drop when optimizing the frequency by moving the 2 coils of the Quadrupole of the Mass Detector,  additionally it was found that the supply voltage is somewhat high (120 – 121 VAC) and it is reported that there have been blackouts in said electrical supply…  I attach the tests performed. 

According to these diagnoses I wanted to highlight some questions:

1. Can it be said that the Side Board failed? ... The consultation is because it is an expensive piece and we want to be sure that it is what we should buy.
2. We also receive indications that the MainBoard may be affected... if so... does the Main Board of an Agilent 5977A mass detector work for our 5975C mass detector?Reports 16 08 2023.zip

Thank you.. 

120-121 VAC is fine.

The technician "dipped the quad" - that's the frequency optimization described, but doesn't say what the abnormal voltage drop is.  Can you get more information?

This surely could be a side board, but I would want to check a few other things first if I was onsite.  The tests in that report were designed around the 5975 a long time ago. The 5977C uses different tests.

No, the 5977A main board cannot be used in a 5977C.

Thanks for your quick response. 

According to his answer... This surely could be a side board, but I would want to check a few other things first if I was onsite...   Since we do not have the possibility of your visit (although we would love to) ... What can we review on site to give you feedback and get closer to a definitive diagnosis? 

Again thank you very much for your diligence and being so attentive and willing to collaborate with us.

Sorry, I rushed past what you said...and did not look above!  The problem is on a 5975C    not a 5977C, our currently sold MSD.

G3870-67010 is the 5977 Main board and G3170-65010 is the 5975 Main board.  They are not the same.

Have you or the technicians done all of the steps I've recommended in the posts above?

I don't want to tell you for sure that the side board is bad as there will always be other areas that could cause this symptom and I don't want you to spend money needlessly.   Call Agilent and have your local Field Service Engineer troubleshoot it.  They can even install a side board and if that does not solve the problem they will remove it and not charge you for that part.  You would still pay for the travel and labor, or course, but you are only charged for the parts used.