CEMONT TH 1600 Bluemaster – TIG does not work, blown diode what to check?

I warmly welcome.
I have a problem.
I received a non-working inverter welder from my friend for free.
It was never twisted or cleaned from what I know.
I started with a thorough cleaning of all the tiles with compressed air and I noticed that the motherboard is blown so I think the diode (if it is a diode) and the interrupted contact in one of these white rectangles "IRE 4000", which is in the upper left corner (marked with red).
The rest of the tiles is probably ok.
I do not see anything burnt or overheated.
If it's a diode (I marked it in yellow) then what should I buy
I am asking for advice.

Try to find a diagram and for now show the whole plate on both sides.
A fired (probably) starting resistor indicates the need to check the switching transistors (red) and diodes in the vicinity (if any) and the output diodes (black).


I miss a transformer supplying control, because I do not see a low voltage power supply on the board. In turn, these high-power resistors (one of which is burnt) now look like elements of a transformer-free power supply.

It seems to me that it is a welder working in a half-bridge configuration. In this case, high-power resistors can create a voltage divider for the capacitors. Combustion of one of the resistors would indicate damage to one half-bridge branch.

the power supply is on the second PCB but the two wires are black and red. As for the motherboard, they come from the power supply and it is a welding machine with the TIG function

Hello all!!!
nuters1- what you have marked in yellow is the protection diode (transil)
And these large oprniki do not know, you need to trace the diagram

Thank you so much

Good morning!
Could anyone help me find the following zener diode? I can not find her anywhere. I did not even find it in the schematic.



Model: Cemont S 1601

Please, it will really help me. Thank you very much!

30v 1W after 2 resistor 3k3 15w

I believe is the same diode as the other at negative cable (right corner in your photo)

Added after 9 [minutes]:

ZY 30 diode (small one after the two power resistors)