Prestige PIC 20.0 induction cooker slow heating

The induction cooker is making clicking sounds when started and the LED display also
blinks in sync with the clicks. There are no error messages, but the heating is much
slower than normal.

I will appreciate if anyone can provide circuit diagrams /  service manual for this
induction cook-stove. It is probably a clone of some generic Chinese make, and so
any related circuit diagram should be fine. 

The coil is 6.2in in diameter (inductance around 100uH and the tank capacitor is
0.3uF.