Mini PAc/ Opti PAC trackball issue

[Droler]

I have a Happ trackball (standard) and Oscar spinner both plugged into USB MINI PAC interface board. The spinner works fine and the trackball works fine on the Y axis (up and down) but my X axis on the trackball only works about half the time. I can't find the pattern to explain the issue. I have rewired the optical sensors on the trackball, and the problem remains.

If I unplug the spinner the problem does not go away so I do not think there's a conflict. What happens is the trackball's X axis sometimes works fine, then over time it slowly stops going to the right (but left works fine). This of course wreaks havoc on your Centipede score mid-game 

After a bit the left direction will stop as well, and the trackball will only go up and down. Up and down never stop working but this intermittent X axis nonsense makes it unplayable.

Is it possible for the encoder board to be defective and intermittent? Has anyone ever seen this in a trackball before?

It's not the MINI PAC board because I've tried this trackball on an Opti Pac board with the same results.

[Jdurg]

Might be the infamous Happ Trackball optic board failure.  Which revision of the optic board do you have?  (Newer boards that don't have that problem are red, if memory serves me right).

[Droler]

Thanks - looks like Happ encoder board rev J - and they are green...

[scotthh]

If you switch the optic boards and the problem switches to the Y axis, you've proven it's the board.

[Turnarcades]

Yep, definitely sounds like a trackball hardware problem rather than the PC interfaces or software.

[vizzinni]

Try buying new optics from fixumdude http://forum.arcadecontrols.com/index.php?topic=48855.0.  I used a set to refurb an old Wico trackball and they work great.

[Droler]

Thanks everyone - Bob Roberts has a direct replacement for the encoders (and I bought the TB from him originally) so I'm ordering a replacement.

Yep, tried reversing the plugs and the problem migrates right into Y instead of X.

This TB has been in a MAME CP for over 5 years, so it's due for some overhaulin' anyway.

Thanks again to everyone who responded - I'll follow up when I get the part.

[Droler]

OK - I received a new Happ encoder board (the very small PCB with a few resistors, a chip, and photo sensors) from Bob Roberts today and installed it on the trackball, and it's fixed 100%.

For the record - this was a red board as previously mentioned in this thread, and it's working great. Thanks to all who replied.