MKS Gen L - Marlin - Thermistor Set up

Hi Everyone,

Im new to the forum, and I’m having a bit of a problem with my thermistor readings. My Set up is using Marlin on an MKS Gen L, and my thermistor readings are consistently out by about 50˚ so when reading a 100 in Repetier, my thermocouple reads around the 50˚.

I have tried for many days now trying to sort this but to no avail. I have tried different sets of differing sensors:

ATC Semitec 104GT-2
HT‑NTC100K, B3950
SMD Vishay

I changed the hot end element for a standard one, as well as now to a more powerful E3D V6 Hotend Kit High-temperature version at 50w.

I’ve tried 4.7k pickups and without, as well as adjusting thermistor tables etc. Still, Im having issues. If I try to push the hot end up to 200˚ then it tends to throw a

Error:Heating failed, system stopped! Heater_ID: 0
Error:Printer halted. kill() called!

If anyone could walk me through this, It would be much appreciated…Im obviously missing something quite fundamental.

Many Thanks for your help

H