exxos's Atari, Amiga & retro forum

Sorry if this is a silly question - I have Exxos' 1.44MB drive and TOS upgrades to install, and I'm not sure which side of the machine pin headers should face the ST motherboard versus the PCB. If you look at the attached image, there's a flattened side and one with a 'bump' on each pin - I'm reasonably sure the flattened side should face the motherboard, but I also think I've seen them both ways. Can anyone help?

I would use the thiner pins (bumpy, conical side) on the motherboard, because they would slide more easily for installing/desinstalling.

The bolder pins (flatened, cylindrical side) would slide less easily (e.g. 0.6 is the default diameter for via in kicad IIRC), so would have a better grip on the extension PCB.

EDIT : that said, I have never used them yet, let's wait for the answers of experienced peoples :)

On my own TOS switcher I placed the flat side to the switcher PCB and the conical side to the mainboard, much as @sporniket described.

If you ever need to use machined pin sockets, there is a conical depression in the socket side so the pins go as far in as possible and the conical faces mate.

Thicker / shorter pins go in the PCB. Thinner / longer ends in the motherboard.

Because firstly the thinner ends will fit inside socket headers better (If they actually get used that is). While the thicker pins "do" fit in the header sockets, they actually widen the holes and they will no longer fit in the thinner pins.

Also should you need to remove the board, the thinner pins will come out of the motherboard a lot easier than the thicker side of pins.