i remove the board out.

Here what i understand, K2 input (brown) will switch to K1 (red) after relay turn on once power button press in and direct the current to sec board .

Relay is 18VDC power by transformer (from K2) thru smd Z622.

Im not sure what is z622? , i assume its rectifier to supply 18VDC to relay. or any double voltage will damage the z622?

Sorry, I don’t know what kind of miniature transformer is it. Measure the size, lead spacing and the output voltage and see if you can find a replacement for 230V.

If i turn it on with higher voltage, will it burn? or the fuse will gone.

or i just simply not able to turn on?

The fuse (F1) will trip open circuit if connected to higher voltage, it will reset itself when that voltage removed. So it’s unable to turn on at all!

what is see the red wire kind of link (by pass) from this board and go over to the next board which allow for the main transformer to have the voltage change.

You can remove F1 ( just to be safe) and bypass the RELAY1’s contacts to allow the main transformer to have voltage change. However, the front power switch will be bypassed as well! You also need to check where is K3 connected to and see if it can work without power supply to this board.

Relay is 18VDC power by transformer (from K2) thru smd Z622.

Im not sure what is z622? , i assume its rectifier to supply 18VDC to relay.

I believe D3 (Z622) is a full bridge rectifier.

BTW, perhaps you can try remove F1 and add a small transformer with 120V primary in series to the existing transformer primary winding to make it work for 220V mains.

I think the fuse is non reset-able and able to withstand till 300v. here the model i find

Littelfuse 36911000000 369 T1A 300V Fuse micro fuse Time-Lag Radial Lead Square Fuse.

The funny part is i was not able to measure any resistance after the fuse, meaning the 2 legs of the transformer, i suppose it have few milli ohms.

@leecc73

I think the fuse is non reset-able and able to withstand till 300v. here the model i find

Littelfuse 36911000000 369 T1A 300V Fuse micro fuse Time-Lag Radial Lead Square Fuse.

Thanks for the info, in that case, the fuse will blow if exceed its power rating. However, IMO, 1A fuse is too high and unable to protect this transformer.

The funny part is i was not able to measure any resistance after the fuse, meaning the 2 legs of the transformer, i suppose it have few milli ohms.

That’s weird! unless the primary winding is shorted (due to over voltage?), it should has more than 10 of ohms resistance for such a small transformer. I got reading of 24ohms on primary winding of a 24VA transformer and 36ohms on a 12VA transformer. You should measure it with the blue and brown cable disconnected to get accurate reading.

The Transformer is tiny 2VA, such of high resistance.

The brown and blue line is from same source, meaning hot wire.