Need help with this

it is voltage probe


2x 10M ohm resistors connected to the 2 variable resistors , when i measure resistance on the variable resistor i get 50kohm

i have attached pictures i took of the instrument
also i have found some schematics online.

can anyone draw me schematic diagram , i need it to make 10 pieces of the boards to print them with 3D printer.

thank you my friends. ps i will donate :D