Pretty sure this is one of my mods, the ID looks familiar although eBay wiped all the data off the site for past sales so its hard for me to remember.
Is this the one I sent on request with an AV cable? If so it just uses the composite out with that cable. Obviously if the issue was the power supply then it's fixed but there's nothing wrong with the mod as it just pulls video from the regular source.
If this is my mod, you have an option of a future purchase of a Megadrive II SCART for the system. THis would give you a better picture. If you get one though, here's an odd little thing, the socket in the console is upside down. The reason for this is it won't fit flush with the PCB otherwise, due to the solder points that the PCB lacks the holes for. So if you ever go for a SCART cable you need to have the arrow on the top of the plug on the bottom instead. The arrow on the cable I gave you is on the top, because I adapt those cables to whatever system I supply them for.
The Engine needs the 9v source and at least 850mA so be careful. I don't know if I supplied a power supply either (if I did, it's a 1000mA one and therefore fine.) I've been banned from selling these consoles on eBay and had a lot of data deleted by those idiots so forgive me for my forgetfulness.