Fluke 93 Scopemeter Ch B volts/div. switch problem.

[Paceguy]

I have a Fluke 93 scopemeter. There is a problem with channel B. The mv/v switching doesn't completely work. When auto set is pressed, ch b is at 2V. I cannot get it to go up any further when pressing V. I can get it to go to 1V, 500mV, 200mV, 100mV and then 50mV where it stays when pressing mV, but again no change if I press V. The circuit board and button membrane are clean and contact properly. Does anyone know which component(s) could be suspect?

Thanks in advance!