You are in charge for any usage and any injury you can cause and specially to yourself.

Candy UK and Hoover France didn’t wanted to send me schematics but I finally found where problem was. I baught them for nothing on LEBONCOIN, french used online maket. Seems to be same brand as Hoover or rosiere RVI 469 MM

Useful theory of operation for inductive cooking : AND9166-D

 

One side worked well but the other didn’t. When tried to switch ON the defective side, I hear relay switching and immediately after backing OFF.
And the pan was never detected.

Because relay is back off and because you need current in coil to detect if pan is present or not. It is normal that pan was never detected.

I measured voltage drop from logic stuff power supply and when relay (9v) is switched everything drop. So I removed the dual Coil used to switch 220 DC to 12 V and 5V, and applied 13V and 7 V then this was regulated as usual on the PCB card.

After that everything worked well as expected. So I knew my issue cam from this part !

The main issue was capacitor in the tiny supply used for standby power. I Changed the two 400V 10uF capacitor and all around regulator (rounded with red below).