turning a pal megadrive from 50hz to 60hz

Electronically it would work as you want it to if it's what you're asking. So yes it would work. But it would look ugly.

 

I'd just try keeping the wiring not excessively permanent, in case you later decide to add switches.

 

Isn't the link connecting VCC directly to ground?

Traces look awfully thick on the side he's connected on. Not got one in front of me and on my phone, but its how it looks

Jp2 and 4 connections are also directly connected on the side he's link - suggesting they are both the same [I.e. both ground or vcc)

 

Well caught ! Indeed I didn't thought it would be a short circuit. wrong side for putting the blob of solder lol.

 

You seem to be over-complicating this. It really is incredibly simple.

You have 4 jumpers, 2 sets of two. In both set, either one OR the other is connected. And by connected, I mean left pad to right pad. That's why there is a track between two of them.

If you want to change option, you have to cut the relevant track, so it is no longer connected. You then bridge the other jumper in the pair. So cut JP3's track, then bridge JP4. NOT to JP3!

To answer your original question, a switch is a device that turns on and off. It opens and closes a circuit. So you can just replace a switch with a permanent jumper.

What you're actually doing is connecting a pin to either ground or +5V.