This is common problem when the ball does nto drop through the hoop with the opto sensor, once the ball drops and the machine's optos does not catch it you will then get two balls inserted in the shooter lane.

Ball trough issue. Had the exact same issue on my JD a few months ago, one of the resistors on the trough board had a broken leg, little solder...good to go. Pull all your balls out...err....go to switch test mode and put them back in one at a time and make sure they are all working correctly.

Yes - trough issue. I just fixed the same thing. I first replaced the trough boards with the Great Lakes Modular boards from Marco. Then a couple weeks later, the problem came back. Turns out the wires into the connectors that plug into the trough boards were not tight. Use a small screwdriver to reseat the wires, or possibly replace the connector. I pulled the loose wires out, and pushed them back into the connector so a new section of wire would be pierced by the connector. Problem seems fixed now.

Hmmm..if you notice his problem started when adjusted the crane, if it was the trough board then it would have been there before...

Anything is possible, but he says it happens every time he starts with a new ball. Sounds like trough...

A little more info after thinking about it. Your problem may not be a connector or the trough boards at all. The balls in the trough get out of position because it is poorly designed and the balls become magnetic (maybe that is why it happened AFTER you got your crane working). What seems to happen is that the ball in position one (closest to the kicker) gets hung up slightly, allowing all the other balls to be slightly out of position. All the balls should be laying flat on the bottom of the trough. There is a part (from pinbits I believe) that you insert in the trough to eliminate the problem. Make sure you take the thin plastic off the part before inserting it into the trough.

Does this happen when you turn on the machine and play the very first ball? If so, I would look at the trough optos.

Does this happen only after some balls were loaded onto the Deadworld and unloaded (even if it was in a previous game)? If so, the game didn't see the balls unload through the crane exit opto (switch #62) and lost count of how many balls are in the machine and got confused. Check that the opto works, but also that the ball falling off the crane will actually fall through the opto beam. You might have to move the opto location a bit closer to the Deadworld ring.