I've got an old IBM PC JX from 1985. It has three expansion connectors on the motherboard.
The one I'm interested in is for 128K Ram expansion.. It looks like a DIN 41612 connector with two rows of 32 pin holes with a pin spacing of 2.54mm with 64 pins in total. I can find similar matching males with right angle pins, but not with the four key's as shown on the female version. The EXRAM128 is the one further away. The near one is the same, except it has two rows of 16 pins with 32 pins in total and the same pin spacing. Here is a photo of the connectors on the board.
You can see four key's or recesses on the side of the connector.. I can't find any other ones with the same pattern. I'm not familiar with these DIN connectors, so not sure if this is custom or not.. The female does have these keys as well as shown here from one of the 128Kb ram expansion board that plugs into the one on the motherboard.. Perhaps they really don't matter as they are both recessed on the male and female. i.e. the ones inside the mail connector are also recessed. Does it matter then if the replacement male doesn't have these recessed sides?
Does anyone know if these connectors would be stock or customer. I was thinking about creating my own memory expansion card as these are not available anywhere as this PC is so rare. It was sold in Japan, Australia and NZ. Not anywhere else. I think less than 20,000 of them was sold across all countries i.e another IBM PCjr flop for IBM.. IBM made 256Kb and 384Kb expansion boards after the initial launch in Japan, so they are even rarer..
If you really want to learn more about this IBM PC JX Flop I have done a video on it. See here
https://www.youtube.com/channel/UC8JeS2mdR76rNjvzPFCnqbwSimmi
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