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View Full Version : How to apply throttle trimming to KT-19


Jshwaa
2015.03.06, 07:00 PM
If you would like to have throttle trimming on your stock Kyosho KT-19 transmitter, follow this procedure.

Using a Torx T8 driver, take the screws out of your transmitter.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2414.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2414.jpg.html)

Remove the throttle trigger assembly and cut the red and the brown wires, do not cut the green wire. Shrink tube the ends of all but the brown wire leading to the transmitter elecs(despite mine being shown shrink tubed.)

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2426.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2426.jpg.html)

Drill a couple adjustment holes in the housing of the transmitter.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2421.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2421.jpg.html)

Go to ebay or digikey and locate a couple 5K potentiometers.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2415.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2415.jpg.html)

Glue them in place so that the adjusters are over the holes.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2424.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2424.jpg.html)

After glue dries, build the circuit you see below.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2439.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2439.jpg.html)


http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2437.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2437.jpg.html)


http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2436.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2436.jpg.html)

The brown wire from the elecs goes to one side of both potentiometers. The other side of the potentiometers goes to the location seen in the pic. The centers of the potentiometers goes to their respective sides of the throttle potentiometer as seen in the pic. This setup essentially biases the throttle switch to any span of control voltages that you adjust the trimmer potentiometers to.

This leads to some interesting possibilities for adjustments, including flipping the throttle switch completely, to where forward is reverse, and vice versa. The potentiometers can be adjusted out completely to where they are benign to operation. Also, one potentiometer's adjustment effects the other, so to speak, where you can throw off the center by adjusting either one, but if you go back and forth a few times you can re-establish the center and have your span of operation in forward or reverse that you desire. I was able to have a nice limit on forward, and a slow reverse, or whatever....with a 32T motor, and 14T pinion this was handy in my kitchen.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/DSCN2443.jpg (http://s83.photobucket.com/user/Jshwaa/media/Mini-Z/DSCN2443.jpg.html)

Here's a video of the mod in action.

http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/th_throttle_trim.mp4 (http://i83.photobucket.com/albums/j314/Jshwaa/Mini-Z/throttle_trim.mp4)

briankstan
2015.03.06, 08:46 PM
that's a pretty cool mod. great job.

Jshwaa
2015.03.08, 11:00 AM
that's a pretty cool mod. great job.

Hey, thanks! Enjoy! :)