Saturday, July 9, 2016


One issue that can develop with North Coast Engineering’s (NCE) engineer throttles with potentiometers (Cab04P and Cab06P) is that the potentiometer shank can develop a wobble.  The throttle knob is fairly large (a good thing!) so it is possible to put the wrong torque (not the potentiometer rotation—rather more of a side-to side forcing) on the shank.  Alas, one of my throttles developed this malady.  The solution is two-fold:  replace the damaged potentiometer and add support for the throttle knob.

The first step is to acquire a replacement potentiometer.  The NCE website lists replacement parts with this potentiometer listed: NCE Part 524-507 - !online-store/c1n1m/!/Replacement-potentiometer-for-Engineer-Cabs-Cab04-5-6-limit-2/p/40150682
This is a “free” replacement (limit 2), but that is good really only if you have other work going on at NCE.  Another alternative is to go to the “Parts and Pieces Depot” on the NCE webpage and then look at the DigiKey parts list.  Listed there is:
potentiometer for engineer cabs  - cab04 /06   Digikey 987-1276-ND
manufacturer part number  P090S-04F20BR10K
I used this option and ordered several potentiometers, as I can see that over time I may need to replace more potentiometers.  The parts are fairly cheap so order a small batch!

With the replacement potentiometer in hand, I then opened up the throttle.  With this, I could de-solder the bad potentiometer and replace it.

 Throttle opened up for access to the potentiometer, sticking up from the printed circuit board.

Upon reassembly, the second task could be addressed—adding support for the throttle knob.  I cut a couple of thick felt circles wider than the knob.  I punched a hole in the center using a simple punch made from sharpened brass tubing.  The felt disks were then fit over the potentiometer shank, followed by NCE’s rubber disk that fits inside the knob.  The knob was attached with an Allen wrench.  A quick check showed the throttle was ready for service!

 Reassembled throttle awaiting felt disks for knob support.

 Knob attached, batteries installed, and throttle checked.  Good to go!

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