UT181A Repair help needed - is my frontend ic toast?

[protonstorm]

Hi EEV-ers

I noticed low resistance readings on my 3 year old UT181A:

A 3.9Ohm resistor reads as 0.3Ohm in the Ohm Range and as 0.0033Ohms (3.3Ohms) in the kOhm range.
I can't understand where the problem is coming from.

From what I can tell, capacitance readings are also slightly low (100nF reads as 84nF) but mV DC seems to be spot-on.



What I checked so far:
- Checked the 100Ohm resistor for high precision Ohm Range on the back of the PCB, it reads 100 Ohms
- I removed the 3 sections of protection transistors (as outlined) - No change
- I removed the capacitor near the resistance / capacitance Input (as circled) - No change
- I removed the MOVs (as outlined) - No change
- I checked the resistors in front of the output and input pins (Pin 26-28) - they seem fine
- I can't see anything on the board looking damaged
- The 2*2 PTC Thermistors measure 1.15kOhm with only little deviation

ES51997 Datasheet:
https://pdf1.alldatasheet.com/datasheet-pdf/view/456328/CYRUSTEK/ES51997.html

I have no experience in multimeter repair, so help would be much appreciated, if only to point in some direction.
Could it be that the front end IC itself is damaged or needs calibration?