Chromatography Forum

System is a 7890 paired to a 5975C. Been having issues tuning. Replaced/cleaned the source 3 times. Have a sporadic Fault 4 (difficulty with source electronics). Yesterday, had a fault 4 that cleared itself, but the MS seemed to forget all tune parameters. Attempted to autotune to correct, got about halfway through and got this error. Vented, checked all connections, pumped back down and now it gives this error at the start of the autotune. Never seen it before, not sure how to proceed. Google was little help.

Sorry for the small pic. The text reads

"Tune action stopped: -222,"({SP00} :MSC:RDY ON;): Parameter amuo value 256 out of range [0,255]"

Have you tried another tune, stune or a bfb? Agilent tune files can get corrupted and this may be your issue.
There is a procedure to reset that I can't remember off the top of my head.

I've loaded another tune file from a different 5975 instrument, no dice. It will manual tune when I manually set the AMUgain below the max threshold, but autotune kicks me out with that error every time.

If you manually adjust the value down and do a profile scan do you get normal looking peaks?

AMU Offset is the parameter that is out of range, but that would be the Mass Filter Electronics not Source Electronics.

I had my 7000 give the source electronics error once and I had the entrance lens wire touching the side of the source, moved it a little and the problem went away. If something in the source is grounding when it shouldn't be it could cause peak widths to be wide or narrow forcing the AMU Offset out of range in an attempt to correct it. Otherwise it would mean you have a problem in the mass filter electronics or a dirty quad, or just a bugged out file somewhere.

It may help to blast the manifold and the analyzer with nitrogen to clear out annoying dust/ferrule/abrasive particles.