Motor won't spin

[IowaTim]

Lost my UMX Waco in the tops of a tree and had to wait out a rain storm before I could collect it. Plane was structurally sound but the battery was bloated, I assume from the moisture, and the motor wasn't responding correctly. Otherwise in fine shape with all control surfaces responding.

I ordered a new motor and fuselage (to put in a new engine mount as the other one had melted) and installed the new motor. The motor didn't sound like the previous motor and ran backwards. I switched the wires and got it running in the correct direction. It still wasn't quite running as smoothly as the previous motor ran brand-new, so I switched it with the old motor for an experiment. The old motor ran initially but soon froze up. After I switched back to the new motor, the new motor has stopped working. Any ideas??

[xviper]

Being that it sat in the rain for a while, all the electronics could be suspect and one part can burn out another part. I think UMX planes have a speed controller/control board/receiver/servo unit all in one. Maybe that got damaged in the wet.

[fhhuber]

An assortment of possible issues.

To save the RX/ESC board would probably require someone who knows what they are doing to look at it in person.

Melted the fuselage in vicinity of the motor says you left throttle power on with the prop unable to turn. That could have damaged the ESC section of the board.

I've had a model lost in a tree for over a year that just needed some cleanup, paint and a new battery. So there's hope.
The battery being left powering the RX in a micro for more than 48 hrs... its ruined. Low draw and a bigger battery in some larger models it can survive up to a week. (If it goes below 3.2 v/cell its damaged, below 2.5 v/cell damage is usually severe, 0.0v = its done.)

[IowaTim]

I've considered the battery a loss, no sense in risking for a bad battery.

Should I test the voltage coming from the board to the motor? Anyone know what I should be seeing on a resistance meter?

[fhhuber]

Don't do resistance tests without knowing exactly what you are doing. You can easily ruin an Integrated Circuit chip.

I would inspect for signs of corrosion and discoloration of the chips. Clean properly with the appropriate electronics cleaner. (caution there too because of the linear servo wiper trace)

I'd be tempted to just replace the battery lead due to potential "black wire disease" typically associated with a leaking NiCd, it can also occur from exposure to elements with a minute electric charge on the wire (as with a "dead" battery)
This involves some solder work using a magnifying glass to be sure you don't accidentally "bridge" where you do not want to make a connection..

[xviper]

You've already spent nearly $60.00. If you need a new Rx/ESC, that's another $56.00. Throw in another battery and another motor and you're in it for $37.00. That's 150 bucks. A brand new plane would have cost $130.00. Personally, these little UMX planes, depending on what's broken, aren't worth fixing due to cost, especially if left out in the wet that long.

[fhhuber]

If it just needs new wire from the RX board to the battery, the pigtail is cheap. (You have to know how to look the part up... my local hobby shop has them on the wall)

This is why I say it needs someone who knows what to look for and how to test it, to look at it in-person.

Servos move and the motor tried = good signs. But it needs to be properly inspected and cared for.

[Proxima.Variant]

my guess...the motor speed controlller onboard the all in one receiver fried.