Ok, since we are one this, the schematic that I've list VR1 = 1K and R 15 / 16 = 9K09, we already know that VR1 is 2K, so the best is to take out the resistances and measure them and then replace both of them, for new values if you change the VR1 value, I think that Vdc will've better stability and accuracy with this mod.
Now I'm looking at the capacitance, for what I can see on the ES51922 data, R1k (pin 49) and R9k (pin 48) require an precise 1k and 9k resistors, they have 909k (R17) and 9k09 (R19) on the same schematic, and R18 (1k) is this in series / parallel with the other two, for better accuracy should this three be remove and place some precise ones with low % and low ppm/C°?
If you change that would it be better to change also VR3 (10k pot), R33 (100k) and R36 (200k x 4)?
Does VR3 adjust all ranges of capacitance or just one?
EDIT:For adding Capacitance below.
From what I can see on the ES51922 data, page 11 parag. 1.5:
C1 is adjust by itself for 22.000nF range (this should be an precise cap, % and ppm/C°), for more precise readings and stability.
VR3 adjust only 220.00nF = That is C2
10k adjust 2.2000nF = That is C3 (On my schematic there is one 100k resistor between C2 and C3, connected to pin 9 = BUFFH)
The ranges from 22.000µF to 220.00mF are all adjust by the ratio of the pins R9k/R1k, (R17,18,19 network) the more precise this network more precise the ridings on this ranges.
Is my reading correct on this?