Minecraft – Why is the piston powered cobblestone generator crashing minecraft

minecraft-java-editiontechnical-issues

I was trying to build an automatic cobblestone generator using pistons, and while I think the machine should work, it instead causes the Universe to implode game to crash.

The stone is created from water and lava mixing next to a "top" piston, this then uses a repeater to transfer power through the stone when it created and activate the piston – pushing it directly downwards. A few levels down is the "output" piston, which uses the same trick detect when a block has been pushed down in front of it, and will then push it sidewards out of the machine.

The top piston has an override "off" switch in it's loop, which works as a start/stop override for the whole machine.

When I switch the machine on Minecraft crashes – I can just hear a piston going and then "Saving Chunks" and darkness…

Luckily, it seemingly crashes in a recoverable way, my world is still playable after a restart, but with a few "phantom" blocks clogging up the machinery…

So, what's going on and how do I fix it?

Oh, and I'm running version 1.9pre3 with no modifications.


Images of the machine:

Top Piston Construction:

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Bottom Piston Construction:

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"Phantom" Blocks:

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Best Answer

This is a bug in the 1.9 pre-release (not sure if just pre-release 3, or all of them).

As you can see here:

enter image description here

It's working as you intended it to in 1.8.1