This article was originally published in RC Driver’s February 2016 issue.
By Charlie Suangka
What is broken? You’re just driving along and suddenly your RC car or truck stops. And there’s that other all-time favorite, “It was working the last time I put it away.” Tracking down what is really causing the problem can be a nightmare in itself.
Many problems are straightforward. For instance, your throttle operation stops or your steering stops. Those are usually simple to troubleshoot, but experienced troubleshooters cover these basics before getting too crazy with buying replacements.
SIMPLE SERVO DIAGNOSIS
Servo stoppage is typically related to the servo being damaged directly; it could be gear damage or a burned up servo motor. However, other factors can also make the servo quit so it never hurts to cover your basics.
The simplest way is to plug in a second servo to make sure the ESC or receiver battery pack is still giving the receiver enough juice to power the servo. Make sure it keeps working after that in case there is something malfunctioning in the power system to the receiver, whether it’s the ESC, BEC or the receiver battery in a nitro vehicle.
Often, high power servos can overload a BEC or receiver battery and cause the servo to stop working when the servo itself is perfectly fine. Many gremlin haunted users have installed a brand new servo only to have the mystery servo stoppage return on the very next run. This is usually tied directly to a lack of voltage in the ESC’s internal BEC.
MOTOR SYSTEM: IS IT THE MOTOR OR THE ESC?
When the motor system quits, it isalways a challenge to know if it was the motor or the ESC. The simplest test is usually installing a second motor and doing some basic bench testing.
The same principles apply here. The testing should be over a brief period of time and under some basic loads to ensure it is actually fixing the problem. The same testing can be done with a second ESC as well.
WHERE TO FIND TESTING GEAR
These are the times when good old fashioned brick and mortar hobby shops can be true heroes of the RC world. Many have basic testing gear, spare motors, ESCs, servos and the like so customers can do basic troubleshooting and purchase the correct replacement.
If you have a local shop, ask if this is an option. It’s amazing how helpful local hobby shops can be and really, who doesn’t need an excuse to go to the hobby shop, right?
Your RC buddies can be very helpful as well. Most have spare gear just for these reasons!
RADIO SYSTEM UNRESPONSIVE? CHECK YOUR WIRES FIRST
In some situations, everything is dead. Either the lights are on and nobody is home or the vehicle is completely non responsive. Most start with the radio system in those cases and the first place you should focus is the wiring.
Look closely at the wires that run from the ESC, or RX battery, into the RX itself. These wires are where your RX and servo get their power. Damage results in everything not working.
CHECKING YOUR RECEIVER
Next up is the receiver itself. One channel of a receiver can die on its own, causing either the steering or the throttle to work when the other refuses to operate. Test with a second receiver or better yet, another radio system. In a pinch, simply plugging your throttle and steering into another vehicle’s RX and doing basic bench testing will get the job done.
DON’T NEGLECT YOUR ON/OFF SWITCH
On/off switches can go bad as well. They feel fine on the outside, but internally there is no switch action happening. Bypassing the switch by connecting the two wires will rule that out. You can remove the case from the switch and make electrical contact between the terminals without cutting the wires. If the switch is bad, you can simply connect the switch leads for an always on situation.
Long term, this should be fixed. It is not healthy for the system to see the sudden jolt of incoming power with the switch on. The on/off switch in RC electronics is a crucial part of the system and should be used if originally installed. Equally, the switch is rarely cutting power completely; it simply puts the electronics to sleep.
If you are not actively driving your vehicle, it should always be unplugged. Never transport your RC vehicle plugged in or store it plugged in.