Polar EM 115 - Monitor Resolution

I wish you all a Happy New Year.

I'd like your kind help on the following: I turned on the monitor of my Polar EM 115, and realized that brightness was totally dark for some reason, as well as the resolution (text,numbers and characters size) was too large (words exceeding the limits of the screen). I was able to correct brightness with the buttons at the back of the screen, but what about the resolution? I can't find any buttons or information in the manual to correct this.
Generally all features of the machine work properly.

Do you have any idea?

Thank you!

 

Photo attached, to help you understand

 

The adjustments are inside on the board. Please be very careful from high voltage inside.

 

Hello. Thank you for your answer. So I should look for a switch, or something similar that can be adjusted manually on the surface of the board? I haven't taken it out yet, I want to be sure.

 

They are potentiometers affixed to the PCB board. This may not be the problem but its the first place I would look. Again be very carful if you are new to this.