Servo tray for KST A13-610 servo replacement in TBS Mojito

August 24, 2025 update: Made a stronger servo holder to prevent servo from jumping out of socket on hard landings or under stress.

The KST A13-610 V8.0 servo has been suggested as a good replacement for the stock Mojito servo. But upon receiving it, I found it fits but its a bit shorter than the stock servo by about 5mm. As a result, you can't use the KST servo horn and the Mojito horns don't fit. The solution I found was to adjust the servo bay to move the servo 5mm toward the control rod. Once installed, you can now use the KST control horn cut down to size with the innermost hole drilled out as shown in the picture (5/64 drill bit works well).

Print out of something strong. I used ASA at 100% infill. Print with supports. Mirror the print for the other side.

Remove the existing servo tray by pouring some 99% Isopropyl Alcohol into the bay and around the edges. Slice around the edges with a fine blade and then grab hold of the plastic bay with some pliers and pull it out. It should come out quite easily. The new tray fits well but it helps to remove a tiny bit of foam along the angled edge as shown in one of the pictures. Glue it in with Goop or E6000 along the bottom and edges.

Shorten the control rod by tightening the ball links on either side about 6-7 turns. It will require a little adjustment (aligning the control horn properly on the servo teeth) to get the midpoint properly set.

For the air brake, you can use the stock Mojito aileron servo moved over. I chose instead to use a GDW RS0708 servo which has more torque and can handle higher voltage than the stock servo. It fits using my servo tray insert here: https://www.thingiverse.com/thing:6979378