Siemens Multizet A1000

[ac_dc]

Hi!

I have a Multizet A1000 from Siemens; when adjusting the pointer
to the 0 position with the E-front rotary switch I can not do that
pointer to 0. According to instructions one should then internally with the
R41 20K do the zeroing. I would complete the device
Dismount to access even on the bottom of the motherboard
to have. Despite the schematic it is confusing which the R41 really is
is ...

greetings

[borghese]

R41 is the coarse adjustment and R40 the fine.
Probably some components are aged a lot

[ac_dc]

But they have to be there ... maybe different revisions? While looking at the board I see
unfortunately only a single IS1 (ICL 7614) and left side center
at the T4 (167B).
But there where the "E-Poti" is located R40 2,5K next to it is a poti
but definitely not R41 20K and also no S2 ICL 7614. 

[ac_dc]

Does anyone have such a multimeter and what can contribute?