Ok so I did a bit more messing around with it.
The rgb hubs work in series as I’m sure you all know. Example:
port 2 on the rgb hub only work if port 1 is plugged in.
port 3 on the rgb hub only works if port 2 is plug in etc
If I plug one of the LL120 fans into port 2 on the rgb hub with a LL140 in port 1 and a LL140 in port 3, the port three LL 140 fan stops lighting up.
but again if I plug then LL120 fans into the motherboard the leds work fine. So I’m guessing it ls the pin connection on the LL120 fans? They appear fine and not damaged. Seems odd for three fans to sustain connection damage..