HeathKit IM-1210 Digital Multimeter

Dear Forum Members,
I bought a Heathkit IM-1210 Digital Multimeter, luckily I also have a schematic of that.
But the meter does not work, at least no measurements are performed with both voltage and resistance, the display does work, and responds to the zero setting, the power supply voltages are also present.
Tried to follow the voltage when a voltage of 9 volts is offered, but after the input fuse I don't get much further with this way of searching.
Does anyone know anything about this to get this meter working again?
Yours sincerely,
Pim

Dear forum members,
The cause has now been found, a track of the left switch has broken off, which can no longer be repaired.
If there is someone who has a defective Heathkit IM-1210, I'm recommended.
Greeting,
Pim