What is this ?

This is a small, pre-assembled and tested board meant to be used as a replacement for faulty NEO-BUF custom chips on SNK NeoGeo boards like the MV1A, MV1B, NeoGeo CD...

How to install

Remove the faulty NEO-BUF chip with hot air, remove the remaining solder on the PCB pads with solder braid if the surface isn't perfectly flat. Clean up the eventual flux residue with IPA or acetone. Place the NEO-BUF replacement board in the right direction (see pin 1 mark), align it precisely, solder the 4 corners using a generous amount of flux, then drag-solder all the sides. The small castellated contacts will "attract" solder by capillary action. Make sure none of the contacts are bridged.

If you decide to install the board with hot air, make sure you don't knock off the board's own chips when the solder will reflow.

Thanks

Thanks to GadgetUK164 (https://twitter.com/GadgetUK164 https://www.youtube.com/user/GadgetUK164) for making MVS repair videos, and making me do this. He also designed very similar boards for the same purpose :)