5973 autotune, iso 70

[BCBC]

Anyone see a problem with iso 70 ratio to 69 above Agilent's limit of 1.6 ?
I usually see it on the same instrument; after an ion source change. Runs about 2.0 to 2.2.
Doesn't happen all the time.
Polarity or filament change doesn't affect it that much.
Thank you.

[carras]

I've had some issues with the 70 mass with a 5972. According to Agilent it was due to "dirt" in the cuadrupole. At that time they told me that it would not affect performance or selectivity. I'am still working with that instrument without any problem. By the way, Agilent said that cleaning the cuadrupole was quite risky since it can be broken easily.

[BCBC]

Thanks very much.