Tutorials/Repeater reboot system

Redstone repeaters and redstone torches will freeze in an 'on' state when the player exits then reloads the  chunk. This is likely caused by the game being interrupted as the circuit is attempting to update. This is primarily an issue for clocks, but can affect any repeater or torch.

To fix this, the player must force an update in the frozen parts of the clock. This can be done by rebuilding part of the circuit or, more commonly, updating the surrouding blocks.

But What's an Update?
The game keeps things in order by updating blocks whenever something happens around them. In a new world where sand is generated without support, the player can walk on those blocks like normal. But when the player updates the sand (by placing or destroying a block, for example) it will fall, and the falling sand will trigger an update for adjacent floating sand, which will update other sand, etc. Essentially, it is the game's way of checking if everything is alright. And the player can let the game know where to check by forcing an update.

Manual Torch Reboot


This is a simple clock deisgn that is fairly flexible and uses four repeaters and four redstone wires. To force an update on this clock, place or replace a torch in the center. This is by far the simplest method, but can be time consuming and the central block is not always accessible to the player.

Manual Button Restart
Since repeaters only take input from the back, any redstone signal sent to the side of the repeater will force an update without interfering with the circuit. Send redstone wire into the side of all repeaters in the clock and wire that together to an easily accessible button.

Piston Reboot
This design uses a piston to update the block in the center of the clock similar to the Manual Torch Reboot. The addition of a piston allows the extra wires to be further away from the clock than the Manual Button Restart. Other clock designs may need additional pistons to force an update in all repeaters.

Automatic Reboot Using Minecart
This method uses a small circular track with a detector rail and  powered rails. Wire the detector rail to the side of the repeater. Once the minecart begins moving, the detector rail will send a signal to the side of the repeaters, periodically forcing an update. The minecart will retain momentum when the world is reloaded.

Trivia

 * Buttons, pressure plates and detector rails can also become stuck in the 'on' state. However, these cannot be forced to update. They will fix themselves eventually, but often it is faster to destroy and replace them.