negative baseline

Hi, I have a Shimadzu 2010 pro and every time I start it and run the first measurement the baseline is severely negative . I press the " zero adjust" and the baseline zeros out but is the correct way to deal with it? I replaced the jet and liner, and septum etc but no change. I was going to try baking out the trap on the N line and purchase a trap for the hydrogen line. Any advice would be appreciated.

Equipment: Shimadzu 2010 pro