>Dear list members: >We have a Micromass Optima with Isochrome continueous flow interface here at >Iowa State University. Recently we are having a vacuum problem. When CRT7 >valve is closed, the vacuum reading is only 3.6E-6 (normally it is >about 1E-8 mbar). This happened gradually. If we reopened and then closed the >valve, we can occasionally get a vacuum of 1E-7mbar. But now we can only get >3.6E-6mbar no matter the CRT7 valve is closed or not. We changed a new >copper pad seal, a new knife edge and a new wavy washer, the vacuum is still >3.6E-6mbar. We degassed ion gauge, the reading is still same. When we tried to >degas the ion gauge again, the computer gave us message, it reads "ion gauge >1 bad calibration data" and no vacuum reading in ion gauge display. I >rebooted the computer but everytime when I try to turn the ion gauge on, I >gets the same message. Any suggestions regarding to these two problems will >be greatly appreciated. This may sound stupid, but have you checked to make sure the guage is giving proper readings? One of the two vacuume guages on our Europa 20/20 analyzer went out and started giving readings in the range you describe even though background scans of the closed-off system showed normal readings (i.e. very low amounts of anything in the system). Luckly, the guage "fixed" itself over time. I guess it was just dirty. Sorry, but I have no idea about the second problem. Good luck. Myq -- ----------+-------------------------+------------------+ | Myq Larson | Stable Isotope Analysis | [log in to unmask] | | | Utah State University | 435.755.6753 (h) | | Knowledge | 5305 University Blvd | 435.797.0060 (w) | | Liberates | Logan UT 84322-5305 | 435.797.1575 (f) | +------------+-------------------------+------------------+