How to find a player's redstone clock (or other aggressive circuitry)?

Solution 1:

There is now a Bukkit mod for detecting and teleporting to redstone clocks: the sensibly-named Redstone Clock Detector.

Solution 2:

If you have access to the world file you can use a map editor/viewer to get a view of the map, and then do a filter just for redstone, overlay the second image and you will know where all the redstone is, it shouldn't take long to find the clock.

Solution 3:

If you don't have access to the world files or the server configuration, use a custom texture pack that makes all blocks except for the ones likely to be in the mechanism (e.g. redstone) semi-transparent. Then, it's a matter of walking around until you see it: even if it's underground.

You could do it fairly quickly by editing terrain.png in your own custom texture pack, but there are several texture packs that do the same thing (like, for example, Strongestcraft).

Solution 4:

I can't believe no one commented on Opis, by Professor Moebius: http://www.minecraftforum.net/topic/2104497-164server-admin-opis-112-alpha-now-with-entity-support/

This is a server side Forge (and client side for the admins) mod, and if you have option to use it (turn a vanilla server into a Forge one, or a Bukkit server into a MCPC Plus one), this is THE solution to this problem.

Opis is a Forge mod that allows to profile how much time is spent in each mod, chunk, even mob in the server. It shows the info as overlays over a modified open source minimap mod, and allows for tricks like teleport the admin to the close vicinity of a block or creature causing trouble, mark with a red transparent block the conflicting block, see what Forge mod causes the worst trouble... It works with vanilla or Forge modded blocks, so it can find poorly designed redstone clocks or hopper chains in a heartbeat anywhere in a server.

Direwolf20, a famous youtuber known for modded let's plays and mod reviews, made a video showing this mod: