24V Heatbed upgrade for the K8200 (New power supply 15V/24V)

This is my power supply upgrade for the K8200 3D printer.
Thanks to edirol and the othe users from the velleman forum.
The schematic shows the litle PCB in the backside of the case,
The first part of the schematic is to switch 24V for the heatbed with the original 15V connector.
The second part controls the light and coling fan of the power supply.
It is a monoflop and it is possible to retrigger,
so the light and the fan will start with the heatbed and stops 1 minute after