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All such calibration pots are famous for instability ( especially at handheld products due vibrations).

Modern multimeter design 2005 and later they have as standard, calibration functions due software ( Goodbye Pots ).  :) 

Test and Trial of few pots stating of high value ( 100K ), this is a good way to start your repair.
Few years back I was had an personal archive of ancient (low cost) multimeter schematics, as assistance for repairs, later on I did realize that restoration of ancient meters, this is bad for our brain cells.
Modern tools are so much faster with new functions, these making them 80% more productive and compatible to modern applications.

This Bosch meter internals (components) are interesting, this meter using high quality parts, and this translates to improved electrical safety for the user, and also better accuracy in Law of Ohm measurements.   

I wish you good luck at repairing it.   
The circuit configuration its a simple divider, from 10k to 100kOhm works, but I not trust on the device consumption and stability at all. Again, thanks for the help.

I have few ideas of my own, about suggesting to you .... trying few random values of pots and see which works best.
But more appropriate way this is you to contact Bosch, and ask their help and to test their after sales support ability.  :)

Did you request schematic by them yet ?  If not try it and let me know tomorrow or when you will have news.
AC / DC voltage and capacitance read but no longer have correct over read adjustment. Continuity (beep), resistance, frequency, RPM and current strength are OK.
I never have the chance to see such a meter internals.
I was hope this to be another Mastech  PCB clone ...  But this is different.

Which function this not functioning due this damaged pot ?
Thanks Kiriakos, I edit the post above with the image.
This entire board has different settings from all others.
I did Fix it ... now you can post attachments. 
Find only this options : Attachments and other options

    Notify me of replies.
    Return to this topic.
    Don't use smileys.

Using firefox

Part 2  ....  Title: Wise power supply selection.

MITSUMI SR296 T2AH250V Switching power supply this belong in the era of 2009, but still this is a superior Switching power supply with:
a) ADJ 11~13V
b)  Noise Free
c)  Made in Japan.
d)  12V rail this is 1.8A.

By setting it at 13V now this will become an truly reliable power source for my new project.  8)
Hello everyone! I have one of these Bosch mmd 302  to fix, but without an electrical schematic I canot find the correct value of the Vr3 resistor. He was lost and only the terminals remained. Thanks on advance if anyone has one and can look at the value of the resistor. Below is the image of the position of the missing component.
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