Well, to begin with, you do not start pumping gas and turning the electronics on until the whole system is under high vacuum, i.e. the vacuum pumps (roughing pump and hv pumps ) have been on usually overnight.
1) pump down to around 1x 10 to -6 mm
2) electronics ON
3) Gas flows ON
4) set temperatures of source etc.
5) Allow 4 & 5 to stabilize
6) Infuse a solution of your tuning compound
7) Optimize the signal over your range of interest (m/z 200 -700)
Enter your method descriptor (scan m/z 200-700, generally 1 sec)
Let us know if this works for your system.
Regards,
MOTOBALL