Repeated failure of primary fuses on Agilent MC 5975C

Question

We are having repeated failures (3 now) were the MS just shuts down. I can replace the fuses, but I wondering why this continues and if this is indicative of a bigger problem. I would like some advice how to troubleshoot. Thanks!

Jennifer Jones

Admin · Accepted Answer

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james_jenkins · Answer

Hi Jennifer, Soccerdad is correct. Rough pumps as they age will start to draw more current through the AC board on the MSD. The slow blow fuses will run hotter and near their limits. The rough pump replacement should cure the fuses blowing. I would replace the pump as soon as you can as the extra demand can be a strain on the AC board. The new Pfeiffer Duo Rev G is the supported replacement G3870-80055 . Regards James

soccerdad · Answer

Hi Jennifer We had an GC-MS issue in the past where the rough pump was starting to fail and as a result kept drawing too much current, causing some of the fuses to fail. We also had an issue with a rough pump (on a LC-MS) which was blowing fuses when it started. For the LC-MS rough pump we connected it directly to power rather than to the MS and start it that way. Once it was running we were then able to turn it off and connect it back to the MS and then start it - I was told that sometimes if the pump/oil is cold the current draw can be too much for some of the fuses. Not sure if you can try something similar for the GC-MS rough pump. Not sure if this helps at all Kevin