Help me to Repair my Korad k3005d

[anilchowdary]

hello all ,  recently i've charged a lead acid battery with my korad ka3005d , after a day it showing faulty readings, while on zero voltage range , it showing 3.3v output , i've inspected pcb nothing burned , everything fine but i got fulty readings , please help me solve this

[Swake]

Search on this board and you'll find the answer or at least something very near to it and a schematic.