Version 2.2 of the PCB built for Gorf including the 5v regulation to power the MiSTer direct from the cabinet’s power supply.
This version uses a 2 amp version of the 7805 regulator and a couple of smoothing capacitors and takes power from the 12v line on the cabinet.
An alternate version uses a commonly available LM2596S DC Buck Converter which does a similar job. Beware – if you use one of these you need to set the voltage to 5V BEFORE connecting to the DE10-Nano. The one I purchased came setup for 9V.
Another option is to put a solder blob on the pad labelled “Direct_5V” on the PCB, and the 5v line from the cabinet is routed directly to the DE10-Nano. I would not use this personally with the original linear power supply, but it may be an option if you have a switcher in there instead.
Finally, the option used on most of the boards currently installed, just use the PSU that came with the DE10-Nano and connect it to the 240v line inside the cab.