I'm using my cable right now and it works fine. I measured all the voltages and confirmed each of the pairs. Yes, all three grounds are common - they're shorted together. Yes, all three 19V lines are common - they too are shorted together. All the ground are just grounds - all the 19V are just 19V. No.. I didn't use a scope to look for secret signals on the lines - I don't have a scope. And no one does that on a $25 bog standard Chinese power supply. If you look at the photos in my other post on the dock disassembly, you'd SEE that there are common pins - you can see it right on the traces on the PCB. As for why more than one voltage or ground line - take a look at almost ANY multipin connector and you'll see they do the exact same thing. It's a common practice. The multiple grounds are used to reduce noise between signal lines. The power lines are duplicated to spread the current draw. Those PCB traces are SMALL.