I was having trouble with the sensors in front of the bulldozer losing sensitivity, or quitting altogether, and I had to adjust the pots on the eddy boards frequently to get the sensors working again. I did some Pinside research and it seems that the problem is with the 10K pot on the eddy board getting worn and moving as a result of vibration from game play and the shaker. I replaced the old pots with a type of Bourns potentiometer that requires 25 turns on the adjusting screw to go from 0 to 10K ohms versus about 3/4 of a turn on the old one for the same range. My thinking is that the adjustment is not only more accurate, but they should be much less prone to movement from the shaking. Time will tell but it is working out great so far.

Note that the white goo in the picture is silicone that will be clear when it cures.

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I purchased mine on eBay for $1 each (three required) and a small shipping charge. Be careful with eBay as there are a lot of generic ones that look just like the Bourns package (hopefully I didn't purchase a counterfeit!). I'm sure they would also be available from Digikey and Jameco (I haven't looked). The ones I purchased had the mounting pins all in a row. There is a package with the middle pin offset that might work slightly better for mounting. I had to solder on an extender to the middle pin to get it to the mounting hole (not a big deal).

Please note that if you mount these, you might need to turn the screw counter-clockwise a fair number of turns to get the LED to light. Each turn changes the resistance a relatively small amount since it takes 25 turns to go from 0 to 10K ohms. Once the LED is lit, turn the screw clockwise until it goes out and you should be set.

This is a great semi-flat black paint from Menards or Home Depot. About $4 per can.

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