Field guide · #5.11
Top-Bottom Joint
How it works
(1) One of the most ingeniously engineered slot cheating devices, popular from the 1970s through the mid-1980s. The tool consisted of two parts: the “top” was a metal rod with its end bent into a hook or “q” shape; the “bottom” was a long wire (often guitar string). The wire was inserted through the coin payout chute, making contact with the internal circuit board and sending a low electrical current through the unit. The hooked metal rod was inserted into the coin slot. When both pieces were in position, they completed an electrical circuit powerful enough to “hot-wire” the coin hopper, triggering an immediate release of all stored coins. (2) A classic two-part mechanical device used against older electromechanical slot machines. A wire inserted through the bottom hopper and a bent rod through the coin slot completed a circuit that triggered unauthorized coin releases. The bottom piece (a long wire) is fed up through the bottom hopper to reach the circuit affecting hopper control. The top piece (a thicker gauge wire bent in a “9” shape) is placed in the coin slot. Together they complete a circuit that triggers the hopper to dispense all stored coins.
Where it appears
Older electronic-mechanical hybrid slot machines with circuit boards accessible through the coin chute and coin slot.
On the record
(1) This was the device that first introduced Tommy Carmichael to slot cheating in 1980. His friend Ray Ming brought a Bally’s slot machine and a top-bottom joint to Carmichael’s TV repair shop in Tulsa. Carmichael was arrested with a top-bottom joint at a Denny’s on the Las Vegas Strip on July 4, 1985, and sentenced to five years in prison. By the time of his release, the device was obsolete. (2) Tommy Glenn Carmichael’s partner Ray Ming introduced him to the top-bottom joint in 1980. Carmichael used it for 20 years across the U.S. and Caribbean before his first arrest at age 35 resulted in a 5-year prison sentence.
Detection & preventionADVISORY
The paid halfHow a monitoring room catches top-bottom joint, and what stops it recurring, written for the desk, not the reader.
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Published as a detection reference for surveillance, compliance and gaming-operations professionals. Thresholds and tuning are set by the property. Nothing here is instruction: the method is described so it can be recognised.