Oh man
![Face Palm :palm:](https://www.eevblog.com/forum/Smileys/default/xfacepalm.gif.pagespeed.ic.EBDwh1hCfo.png)
"head --> table"
The zero points are shifted. However, the deviation matches the range.
7.998mV in the 10V; 79.97mV in the 100V; and ~800mV in the 1000V range so I suspect a common error. The offset then also runs through all stages with the same deviation.
Wen i was looking for a video disassembling the switches i found the repair of defpom where he repaired a switch shaft.
Later in bed I remembered what else can happen with a broken switch shaft
![Face Palm :palm:](https://www.eevblog.com/forum/Smileys/default/xfacepalm.gif.pagespeed.ic.EBDwh1hCfo.png)
And yes the shaft of the 4th digit ist totally destroyed.
Unfortunately, the latching mechanism is firmly screwed to the device housing and suggests a correctly functioning switch, whereby the contacts set to 8 do not move any further...
Defpom has uploaded a print file for a new shaft piece to thingiverse, but unfortunately it doesn't quite work with our printer. But that's not a problem. At least the error has been found.
I will now replace all the shafts because they are all cracked
Now I'll solder the old UA709 and the old Q39 back in and see if I can manage without recalibration. I didn't have to replace the electrolytic capacitors I've replaced so far. They were all still within the specified capacitance range, even though some of them were a bit high-impedance.
Regards