40 pin cartridge connector (for Atari ST)

Note: as I measured this with a ruler on a damaged connector from an Atari ST I could be mistaken about the exact measurements. For all I know it could be imperial measurements. Hard to tell when using a ruler.

Are you sure it isn't 0.1 inches pin to pin? Best to measure the 20 pin spacing and divide by 20.

How about dividing by 19 rather than 20 since he's only got

I'm assuming he can make the necessary calculations.

Thanks, though I have been known to make mistakes now and then ;-)

It looks like the spacing is 2mm because I have a cartridge expansion board with the connector soldered on the board (easier to measure than a ripped-off connector with bent legs on its own) and I measured just over 38mm from pin 1 to pin 20. That should mean a pin spacing of 2mm:

I don't know why I measure just over 38mm (I don't have anything more accurate than my 2mm ruler, and I would guess around 38.25mm as 38mm is a little to the left of the end pin's center).

The pin spacing can't be 0.1" which translates into 2.54mm because:

OK. That's too bad because 0.1 is pretty common. You're down to wading through the Mouser catalog and the like I guess.

Are there any other alternatives close to 2mm or 0.1" spacing? Or should I just assume that the slightly bigger spacing is just inaccuracy, bent pins etc?

I'll have a look through Mouser and Digikey's catalogs, but I have another question while I'm here: are there other connectors around with the same pin-spacing as this cartridge connector? I'm planning to replace some of those cartridge connectors with a more permanent connection as I don't need them to be detachable.

Have you tried on eBay for (cartridge connector Atari ST)?

Haven't had a look, although that's probably a source for these kind of things. However, I found out that I really don't need the Atari cartridge connector because I'll have several when I've desoldered the ones already existing on my various expansion boards. What I need much more however are connectors that go in place of those cartridge connectors. In other words, I want to desolder the existing cartridge connectors, then insert a reliable connector such as an IDC ribbon-cable connector or something. That way I can connect those expansion devices together without the unreliability of the cartridge "card-edge" connector.

So is there something that will fit the 2-row, 2mm spacing, 5mm row spacing size?

I've taken a few pictures of my cartridge connector and an expansion device which attaches to it:

Can't comment as to size, but many people used a printed circuit card edge as a connector. There also were purpose made male connectors, but I can't point you to a source for the size you want.

Have you downloaded the Mouser catalog pages?

The problem is that the cartridge connector is the weakest link on the Atari ST. It's a known fact that contact problems often occur, which I want to eliminate once and for all by removing this type of connector and using something else instead. Then on the other side (the mating card-edge) I need so solder the wires directly to it. A flast cable would be ideal for this, at least for the card-edge side, but the question is what to use for the cartridge connector side.

I've hear others point out that these connectors were custom made. That might make things hard. If I can't find any suitable connectors I assume the only way to go about this is to solder each strand of a flat-cable into the connection holes on the PCB where the 40 pin cartridge connector previously was. Any better ideas?

I've had a browse through Digikey's catalog, in the connector section, but not found anything yet. Haven't had a look at Mouser yet.

The Radio Shack Color Computer used similar connectors (as did the Model 1) but they were standard, off the shelf parts and you could buy all sorts of after market parts inc. gold plated.