Medusa HV faults on 6520A QTOF


For the past two months, I have been working on repairing a QTOF instrument, specifically the 6520A model, running under MassHunter version 8.00.8058.0. While this instrument is a bit dated, it could serve its purpose well for educational purposes here. We acquired it from another laboratory, where it had been unused for some time.

The instrument is able to reach a good vacuum level (3.2E-6 for the Quad and 3.9E-7 for the TOF), but I'm encountering a persistent issue. Whenever I attempt to turn it "ON," it consistently got Medusa high voltage fault errors, typically error #38, although occasionally errors #34 and #39 also occur. To address this, I got a "tested" G1969-65360 assembly and replaced it with my own, but unfortunately, this didn't resolve the issue.

Interestingly, when I go into manual tuning and set all the HV (high voltage) values to "0," the instrument does allow me to turn it "ON." However, as soon as I begin increasing these values to their default settings, the instrument encounters errors once again and goes to “Standby”. Automatic tuning also results in the same errors.

I've monitored the +24V line, and it appears to be around +23V to +22.8V.

I'm currently considering a few potential solutions:
- Replacing the 24V PSU (Power Supply Unit) as it may be causing the issue.
- Investigating the possibility of software incompatibility with such an old instrument.
- Assessing if the flying tube was damaged during transportation, potentially causing a short circuit at high HV values.
Thank you for taking the time to read through this and for any insights or assistance you can provide. I welcome any other suggestions or thoughts from the community.

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