The DIN should show +5V as there’s a 10k pullup attached. You could try connecting RC1 instead of RC2, as they pulse at the same time anyway.
The incremental behaviour is weird, it’s like the data is being latched on every clock. You’re sure you’ve got RC and SC correct? No shorts, including any of pins PB15, PB13, PB12, PD10 on the Discovery board?
RC 1 instead of 2 - no change of behaviour… and still no shorts at any of your mentioned pins… grrmpf
RC and SC are correct, tried it with different ribbons and straight jumpers…
just to mention, IC 1 on the CORE is a 74 HCT 540 instead a 541… ordered a 541 - they sent me a 540. looking at the specs, it doesn’t matter. right?
i’m getting fuzzy 
That’ll do it, you need the non-inverting 541
bloody!
you got a beer latigit. cheers!
Hey, wait until it works first! But prost/santé/cincin!
Where did you get your chip? The DOUT probably works because all outputs are inverted, whereas the SI will be out of phase with the rest (at a guess).
ur welcome. Reichelt… correct, the outs are inverted. i’m confident it will work after. whoohooo 
yesss, the right chip arrived. all works fine now! thank you guys for your help…
now it’s time to to build the machine!
wicked!