6120B tune gives xx Positive abundances and 100,000+ negative abundances. Help!

Same here. I have 6135B MS. Positive tune abundances tend to zero while negative tune is passing with good abundances.

Agilent_LCMS  Please help.

Durjoy123 First the basics. Change to fresh calibrant. Then turn calibrant on and run a full scan to see what else is being ionized in positive mode, attach a screenshot of the scan please. This will give us an idea of not only the current abundance of tune ions, but what else is being ionized and detected in positive mode. Remember, many compounds that are ionised and detected in +ve mode are not ionized or seen in -ve mode. Negative mode can hide the cause of the issue.

When was your last good passing Autotune in +ve mode? What has changed on the instrument since then?

Charging - while calibrant is turned on switch to negative mode and run a full scan again, wait for the signal to stabilise. Then quickly switch back to +ve mode. Does the abundance of tune ions in +ve mode jump back up for a short time after switching back from -ve to +ve mode? If so then it's possible you have charge build up on Ion rail elements/lenses that are effecting +ve mode ion transmission. A cleaning of front end lens elements is most likely required. In that case I would log a service ticket with your local Agilent Service representatives.

There might also be a problem with the pos/neg power supply in the instrument. Let me know how you get on.

Thanks, we had to get a service call in.  Seems the calibrant was old and stored at room temp.  

Ah the old classic! Looks like I was on the money with my first suggestion then.

Thanks for the update, much appreciated, I have marked this question as answered.