Minecraft – How to use redstone repeaters to stretch the redstone limit

If you watch at about 2:50, you can see most of the left half of the circuit. The part for the stairs looks like it isn't shown very well but that is less important timing wise. Watch carefully over and over and see if you can replicate it this way. It looks like the repeaters for the middle activate and deactivate immediately. So the order (from a circuit standpoint) for both directions is M, L+R. This works for closing because the middle repeaters don't have anything to activate until the blocks are pushed into the middle. When opening, they will retract the middle immediately.

Breaking it down:

Opening

1. Middle repeaters deactivate (middle pistons retract)
2. Delay
3. Left and Right redstones deactivate (left and right pistons retract)

Closing

1. Middle repeaters activate (nothing happens because the middle pistons are not in position)
2. Delay
3. Left and Right redstones activate (left and right pistons extend)
4. Now the middle pistons have been pushed into position and are activated by the middle repeaters

It sounds like a problem with this 2in/1out "device". I would do two things:

1) Try setting it all up in a smaller area and see if the problem persists. There might be some game bug or design flaw caused by the long distance. Also it will be easier to do "debugging" on the circuits if it's all collected in one place.

2) Post a schematic of the device since it is very hard to help without seeing the actual circuits.

Update:

From patch notes for latest patch 1.7.3

Booster rails are no longer being powered magically without a power source

So updating your client might fix the problem now.