These solid 1.25mm pitch connector cable pairs are great when you need something that can carry a couple of amps of current and are easy to connect and…
I’m lining up red wire with red wire, etc … as you say it only goes one way.
I suspect the problem is my age and big fingers on such a delicate connector. And i don’t want to damage it by forcing … If I have to use force to connect them, it won’t be easy if/when i need to disconnect.
In hindsight, not what I should have used to connect 2 boards
No real trick here! As Bob has mentioned, these connectors will only fit together one way which is good. I find that you can put a fair amount of force into them as long as it is evenly applied to both sides of the connector.
It’s a bit of a fiddly endeavour, but for these larger connectors, I find that you can ensure a good fit if you align them by hand, then use two needlenose pliers on each side to press them together. Just make sure you apply even pressure to both sides.