The horizontal now became the vertical & vice versa. This exposed both couplers to the open area of the control panel. One more thing was needed, however. The vertical still operated correctly, but the horizontal tracked in the opposite direction of ball roll.....kind of fun to try to remember to roll the opposite way from what you wanted while playing the games, but.....it needed to be fixed & the fix is to simply swap the blue wire in the header plug with the violet wire to change direction of roll to match the ball travel. Easily accomplished since MTAs were used. All you needed to do was pull the wire out & move it to the other end & push it back in with a jeweler's screwdriver, while off the header, of course.

Moving up to 1999, I find that the new trackball units are being shipped out with the same type modified orientation, even with arrows on them to show direction of mount, however, they did not reverse the blue & violet wires in the harness, so it plugs up from the box with the horizontal tracking in the reverse direction. This is using the assembly with harness straight from the box & mounting as directed. I'd say the best course of action would be to swap the 2 wires, so that the optic encoder pcbs are out in the open area now.....a much better place for them as far as I'm concerned.

Of course, you can elect to take the easy way out & just swap the 2 plugs & disregard the arrow & mount the trackball in the original conventional manner. Now all things should work fine, providing you keep the same optic boards & harness....changing either will have an adverse effect which will require you to do some type of modification. Throughout all of these tests I performed, the one constant in all situations was the ground & 5 volts always remained the same, no matter what. It is possible to insert the plugs backward to the locking ramps, though, so care should be taken to see that they are not & that they are not sitting over 1 pin to the right or left on the header.

Before going on, let me map out the circuit's path for wiring from the main pcb to the optic pcb using a Centipede as a guide since most are the same basic wiring, just starting from different main pcb edge connector pins.

Now I'll go into some of the test results when different variations of harnesses & optic pcbs were installed in Centipede, Millipede & Marble Madness.

The same thing holds true on the vertical pcb connections as you can see the old trackball with pcb and wiring on the left looks much the same as the horizontal wiring did. In looking at the pic on the right that has the new 1999 harness attached, we see that the outside wires used for clk and dir are reversed once again. If you were to change one of the optic pcbs to the newer type, the wiring would be correct in this conventional mounting using the new harness, but the old pcb remaining would need to have the outside wires swapped.

Basically, if the combination of new & old optic pcbs along with new or old wiring harnesses are not giving you the proper direction of travel, you only need to swap outer wires to change direction and you never want to try to swap the red & black wires or insert the connector backward.

Here's a look at the evolution of the TB optic boards that I have at my disposal, albeit incomplete, which are also used in steering wheels & other encoding devices.

On the left is pic'd the mini 2¼" trackball & the 3" midi trackball. At the bottom of the pic is a set of worn roller & idler shafts along side a new set. As you can see the ball will drop into the case pretty deep when the shafts are worn. On the right are all the parts used in the trackball from the plastic housing to the screws that hold it together to encoder wheels. The lamp sockets are for illumination of the 3" translucent balls which many have used in place of the solid color balls for the effect it gives to the CP.