I bought some month ago a faulty and cheap R3131.
I read a lot here about them and realised that I would need an extension card to fix it.
I choose to build one with Veroboard. The base plate I cut in 1.5 mm aluminium on which I bolted the 96 pins Eurocard connectors.
Three Veroboard levels are needed to fill the 96 points.
First level:
To push the next Vero inside I had to remove the little brass posts on one side.
The male wrapping connectors were available so I used them but they were less convenient to solder than the female ones I bought.
Three populated levels:
Of course a careful control is needed before placing the next level.
I added another aluminium plate over the lot with a bending to help insertion. It also avoid to stress the connectors and the solderings.