Receiver Channel Stops working
 

I have a 6 channel micro receiver from Futaba model #R156F. I was rebuilding my stryker and plugged in the esc into channel 3 and the esc would never arm correctly. I tried to troubleshoot and try the esc in a different channel so I put it in channel 6, turned the flap knob and the motor worked like normal.

I also tried to plug an elevon servo into the channel 3 spot and still nothing. Is this normal for a single channel to stop working like this. I want to make sure there is nothing I can do before I buy another receiver. I tried everything I could think of to troubleshoot and still nothing.

Any thoughts???

Thanks for the help,

Viper

RE: Receiver Channel Stops working
 

Have you tried another receiver to make sure the problem is the receiver and not the transmitter?
Are the other 5 channels operating correctly?
You didn't mention which transmitter you were using, but is it possible you somehow changed the programming for channel 3, or changed the transmitter from mode 2 to mode 1 (puts throttle on the right side stick).

It is possible for a single channel to go bad - either a bad output on the decoder chip, or a bad solder connection somewhere, among other things. Could also be a single channel bad in the transmitter.

RE: Receiver Channel Stops working
 

I checked all of that last night. I tried another receiver and everything worked fine. I have a Futaba 6EXAS Tx. The only thing I can think is that it was damaged when I crashed it last time. I hit the wing on a scooer goal but nothing ejected. Can a sudden stop of a motor damage the receiver channel?

RE: Receiver Channel Stops working
 

Does the 6EXA have a throttle lock function? Not a Futaba user here but a number of newer Tx's have this function specifically as a safety feature for electrics and when activated if the button is pushed on purpose or accidently the throttle port will do nothing no matter what you do with the throttle lever untill the button is pushed agine. Check your manual for this function.

John

RE: Receiver Channel Stops working
 

Well, if it works fine with another receiver, that pretty much narrows it down to a bad receiver.
A throttle lock on the transmitter would have affected both receivers the same.

If the other 5 receiver channels are still working, I would guess the ESC somehow damaged the channel 3 output, or something shifted and maybe shorted to the signal wire on channel 3. Does a servo respond at all when plugged into channel 3 (go to one extreme or the other, or just take a random position)? You might also want to try wiggleing the servo connector where it goes into channel 3 to see if there is a broke solder connection.

RE: Receiver Channel Stops working
 

Yes, a single channel can go bad. Had a futaba rec fail on ch 3 also. Worked cold (right after powerup) and after about 5 minutes, ch3 quit responding. Lucky I found it on the ground during setup. Sent it in for repair and they sent it back and said it was cheaper to buy another.
Edwin

RE: Receiver Channel Stops working
 

Thanks for all the help. I think I will just buy a new receiver and take this old one apart and tinker with it as I am going to school for an electrical engineering degree. Maybe I will learn something!!

RE: Receiver Channel Stops working
 

Have you checked the end trims? Some of the esc's wait for low stick and if you have the trim up it will not arm.

Tony

RE: Receiver Channel Stops working
 

Checked It twice. I have ran through everything everyone has said to check then some more then done it again just to try and aviod spending money on a receiver that could be spent elsewhere. I do definately appreciate all the suggestions. Hopefully my loss will have helped someone else avoid needlessly buying a new receiver.

Question If I do peruse the electronics in the receiver what should I be looking for. If indeed the channel was hurt by over voltage or something will there be something specific that maybe should stand out? Just a thought

Viper87

RE: Receiver Channel Stops working
 

Have you tried jiggling the connector? While I think it is possible for one channel to go out, a lot of times it is something simple. In this case maybe one of the pins got partially pulled from the solder joint hence no continuity. That's what I would check next anyways;) Good luck!

RE: Receiver Channel Stops working
 

Viper87, you say you are going to an electrical school. If so, I'm sure they have oscilloscopes in the labs. Just look at the suspect channel with the scope to see if you are getting any output. Most probably you have a bad connection between the decoder chip and the output pin else the rudder channel would not be working on a Futaba receiver. If you hook the scope between the ground pin and the signal pin you should see a positive going pulse about 1.5 milliseconds wide every 20 milliseconds or so. The width of the pulse should vary between about 1 to 2 milliseconds depending on throttle stick position.

RE: Receiver Channel Stops working
 

Good choice on the engineering school! Good luck, hope it works out for you. I got my degree a long time ago, back in 79.

It's too bad that there aren't heathkit and ace radio kits around any more. My first RC system was a heathkit 8 ch, and you can learn quite a bit about the way RC stuff works by building kits and paying attention to the test waveforms, etc, in the manuals. Oh, well - those old radios weren't quite as reliable as the great ones we have these days, plus they weren't cheap! My heathkit was about 250 bucks, if I remember correctly. That was in 1973.. that would be quite a bit more in today's dollars, and you can STILL get a heck of a radio for 250 bucks, which makes today's stuff a bargain in comparison.

Take a good look at the solder joints on your RX with a magnifying glass, you might find something. Either that, or you'll find that the decoder IC that sorts all the pulses out has been damaged on that one input, and it takes pretty special tools these days to remove & replace surface mount IC's. For what labor costs, Futaba is probably right - costs more to fix than a new one.

You might look at the hitec Electron 6 - it's a nice light receiver, and I've had pretty good luck with mine. Might not be as expensive as a new Futaba.