You did really well. Now please tell us the multi woks beautifully.since the suggested pins are not enough to replace all the row, I've cutted the broken pin from the pinheader and changed only that with one of those suggested. It's not too ugly I think.
At the beginning I had some audio issues due to a jumper cable that was too loose but I've used some new cables and everything worked.
thank you @Apocalypse !
Unfortunately I discovered to have a broken C2 motherboard..In the past the precedent owner or someone else connected the jamma connector upside down and 2 diodes arrays were burned.
I think that IC1 is broken on the 2P B2 and results always pressed. I'll need a new C2 unfortunately or a 315-5296 IC but I don't think that will be easy to find it..