Hurco Trackball replacement / retrofit

Hi all,
Well, the trackball on our Hurco KMB CNC finally died - apparently a common problem for machines of this particular vintage - and a web
search for a replacement found us gizmos in the $250-$800 range which was a bit much for my Scotch ancestors...
So I figured out a $40 replacement...
From a web search I found that what usually gives out is the little sponge donuts on the optical encoders that the ball contacts. That's what happened to me, too. Although replacing the donuts was an option, I went for 'Plan B'.
I probed around in the Hurco and found the optical encoders were outputting relatively standard 5 volt signals in phase quadrature just like other optical encoders we use.
And I figured most any computer trackball can probably do the same thing.
So I tottered off to Fry's and got the cheapest trackball on the shelf, popped off the cover and probed around inside it and found the X-Axis and Y-Axis quadrature signals, kludged some wires from the new trackball to the Hurco and voila! we're back in business for $40 (the cost of the new Kensington trackball) plus a couple of hours of my time.
With the new trackball double-stickied to the Hurco control panel it looks like our machine is being assimilated by an extra-terrestrial... but it works for now.
I probably only postponed the inevitable of converting the Hurco to a PC-Based CNC driver, but it was a fun project for the day.
Carla
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On Tue, 14 May 2013 08:14:43 -0700, Carla Fong
WELL DONE!!!!!!!
--
Unka' George

"Gold is the money of kings,
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replying to Carla Fong , mdh wrote:

Would you be willing to share the schematic foryour modification?
Thanks in advance.
Mike
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):

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