Home | About | Contact

Calibrating the Rotating
Playfield

The position of the rotating playfield is determined by two different sensors. There is an encoder mounted on the centre shaft which provides an absolute rotational value of the playfield position. Secondly, there are optical sensors which provides exact positioning for the four play positions. In simplified terms, the encoder tells the logic board which player to turn the playfield to, and the optical sensor provides an exact position to the logic board for the playfield to stop.

To calibrate the playfield, remove the glass cover and remove the ball from the outhole. Make sure all the hardware is securely fastened, the V-belt is snug and the set screws on the pulley shafts are tight.

Test #4 , accessed from the keypad, provides a read out of the position encoder. After Keypadpressing the Test #4 key, manually rotate the playfield. A value between 00 and 77 will be displayed in the "Ball" digits of the centre display. Value 00 should be North, 20 should be East, 40 should be South and 60 should be West. When finished with Test #4, press "End" before entering another test key.

Test #6 provides a read out of the optical sensors. When approaching a play position, the number 1 or 2 will be displayed, also in the "Ball" digits. When at the correct position, the number 3 is displayed.

If either of these tests do not display these values, playfield rotation will not occur properly or even at all. Before proceeding any further, these repairs must be made.

If the readouts are displayed as described, manually position the playfield to the North position and press #6. Position the playfield so that the number 3 is displayed. Now, press "End" then press key #4. If 00 is displayed, the table is calibrated and should be ready to play. if a value other than 00 is displayed, the encoder will need to be adjusted.

To adjust the encoder, there are several small set screws on the rotational shaft just Encoder Adjustabove the pulley. Loosen the set screws and turn just the encoder shaft to read 00 while keeping the large shaft with the pulley stationary. Tighten the set screws, ensuring the reading remains at 00, then go to test #6 and ensure that 3 remains displayed.

The playfield should now be calibrated. Don't forget to place the ball back in the outhole.

If during play, the table continues to "search" for the exact position, there may be loose hardware. This can be caused by loose pulleys, a loose belt or the bottom bearing bracket may be loose on its mounting screws. This bracket can be accessed (with some difficulty) by lifting the game out of the cabinet and tipping it to access the bottom of the mount. The 4 mounting carriage bolts can then be seen. Replacing them with 1/4" bolts will secure the hardware.