Hartmann & Braun, Pontavi WH2, repair schematic

[carbono.silicio]

Hello all,

I've bought this used Volt/Ohmmeter and would like to restore and repair it.

Hartmann & Braun, Pontavi WH2

From a quick look inside everything looks ok and the needle is also ok but i can't get Resistance reading.

Does any one have a full schematic of the circuit? The online manual only shows part of it.

Thank you very much,

Nelson