I bought my ender 3prp a week ago, had some decent prints in the beginning although they were short prints they were good. Recently I started getting the thermal run away error. Where the print would stop mid way. This error usually come in after 15 mins of the print.

I decided to heat the nozzle and bed to 200 and 60 respectively and saw if it remained stable. After about 15 mins again I saw the drop in nozzle temp from 200 - 195 after which I got the thermal runaway error.

I would expect there is something wrong with my PCB as the temp is displaying to drop, indicating that the thermostat is working. The hearing element must work as its in a steady state for 15 mins.

I would like some input on it please and thank you.