At 03:47 PM 5/6/98 CDT, you wrote:
>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.
>---
>
>Jin Wang
>[log in to unmask]         U            1127 HNSB
>(515)294-9421(LAB)       S
>(515)294-3926(O)         A            Iowa State University
>


Jin, We have a VG Optima and recently had a similar problem (error meaasge
that reads bad calibration data). Our problem was solved by replacing one
of the relays on the ion gauge board in the vacuum gauge monitor box. Good
luck.