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Issue with servo Y-cable

#1
Hi, this is my first post on this forum.
I'm having an odd issue with a y-cable I purchased off Amazon. I use a flysky i6-x transmitter with a flysky ia6b reciever. I have two 9 gram servos connected to a y-splitter for my ailerons. After plugging my system in and connecting my transmitter, any aileron commands result in the system shorting out. If I move the right stick, the two servos just go nuts for about 2 seconds, and then lock in one direction, as if they're trying to go out of their range. After this happens, I'll I unplug everything because I'm afraid I'll ruin the servos. I have no idea why I'm having this issue, as I've done as much troubleshooting as I can. I've tried differently y-cables, tested it in different channels, tried different servos etc... Does anyone have any suggestions on how to fix this? Any help would be greatly appreciated, as I'm relatively new to electric airplanes. Thanks a ton for the time,
Santino
 

quorneng

Well-known member
#2
Tackle the problem logically.
Test each servo connected directly to the rx without using the Y lead. If one still misbehave then you know it is that servos. If both still misbehave then it is something to do with the radio side. If they both work normally then you know it must be the y lead and it needs replacing..
 

FDS

Well-known member
#3
Also check you have the pins in the right way on both the Y lead and at the receiver, the ground is usually the bottom pin on the RX, if you start at that end and get it right then be sure the polarity stays the same all the way through.
Did the rudder and elevator servos work correctly?
 

Hai-Lee

Old and Bold RC PILOT
#4
It sounds about the same as what happens when the ESC/BEC cannot drive enough current and shuts down the 5V rail totally for protection, (either overcurrent or over temperature).

What is the BEC current rating? Also try connecting only one servo at a time and testing them separately. It is possible to have a servo that is binding or has damaged gears that will draw as much current as it can trying to turn. Also if both servos work OK separately then ensure that you remove all connections from the Rx except the ESC and the Aileron "Y" harness and repeat the test.

Until I know the rating of the BEC and the total load, (number of servos and any other connections), I cannot advise further! I await your response.

Have fun!
 
#5
Tackle the problem logically.
Test each servo connected directly to the rx without using the Y lead. If one still misbehave then you know it is that servos. If both still misbehave then it is something to do with the radio side. If they both work normally then you know it must be the y lead and it needs replacing..
I appreciate the help. I've tried replacing both, with no success. The Y-cables I bought came in a pack of 5 and I've tried all of them. I also have cycled about 6 servoes through each lead as well. This is why I'm so confused on what my issue is.
 

PsyBorg

Wake up! Time to fly!
Mentor
#6
Did you jumble your extra wire together and tie em together in a neat bundle?

I had the same issue on a 3 camera video system when I bunched to long wires together to get the cameras within arms length for testing.
 
#7
Also check you have the pins in the right way on both the Y lead and at the receiver, the ground is usually the bottom pin on the RX, if you start at that end and get it right then be sure the polarity stays the same all the way through.
Did the rudder and elevator servos work correctly?
I'm confident the leads are correct, and just for kicks I even tried reversing them in different combinations in case something wasn't wired correctly, with no success. The rudder and elevator both work, and ive used the same servoes on alierons inserted separately into the reciever (with a mix) with no issues. However, my current build is a p38 that utilizes differential thrust, and uses my only three mixes to operate, so the mixing isn't an option
 
#8
It sounds about the same as what happens when the ESC/BEC cannot drive enough current and shuts down the 5V rail totally for protection, (either overcurrent or over temperature).

What is the BEC current rating? Also try connecting only one servo at a time and testing them separately. It is possible to have a servo that is binding or has damaged gears that will draw as much current as it can trying to turn. Also if both servos work OK separately then ensure that you remove all connections from the Rx except the ESC and the Aileron "Y" harness and repeat the test.

Until I know the rating of the BEC and the total load, (number of servos and any other connections), I cannot advise further! I await your response.

Have fun!
As far as I know I don't have a BEC installed, however I believe my ESCs are rated for 30 amps. I'm running a 3 cell connected to a battery Y-cable, which splits off into 2 ESCs and motors, respectively. As per this video that I watched:
so I disconnected one of the positive leads in the ESC. My current set up is one 3 cell battery, two ESCs and motors, with one disconnected positive lead, one elevator servo, and of course, the disfunctioning y-cable/servoes . Hopefully this is enough info for you to help me!
Thanks,
Santino
 
#9
Did you jumble your extra wire together and tie em together in a neat bundle?

I had the same issue on a 3 camera video system when I bunched to long wires together to get the cameras within arms length for testing.
I didn't, however I dont understand how this would help, is it something to do with the signal? I don't have much excess wire, as the mengths and extestions I have fit relatively well
 

PsyBorg

Wake up! Time to fly!
Mentor
#10
Cool. Was just something I had happen with similar results.

Signal induction into unshielded wires is common. If your wires are separated then I would agree to look at your power side.
 

Hai-Lee

Old and Bold RC PILOT
#12
If you are using the iA6 what does the Rx voltage indication on the Transmitter indicate when the servo lock up occurs?

Have fun!
 

Hai-Lee

Old and Bold RC PILOT
#17
OK 3A UBEC should be enough to power a good number of Servos that are stalled. Next thing to check is the actual temperature of the servos and the ESC when the problem occurs! be careful because if there is a fault then they may get quite hot!

Another thing occurred to me is that you need to make sure that your transmitter batteries are good also. On my iA6 I actually had forgot to replace the Tx batteries and everything in the plane eventually just locked up because the Tx effectively wasn't transmitting.

Let me know what you find if anything!

have fun!
 
#18
It sounds about the same as what happens when the ESC/BEC cannot drive enough current and shuts down the 5V rail totally for protection, (either overcurrent or over temperature).

What is the BEC current rating? Also try connecting only one servo at a time and testing them separately. It is possible to have a servo that is binding or has damaged gears that will draw as much current as it can trying to turn. Also if both servos work OK separately then ensure that you remove all connections from the Rx except the ESC and the Aileron "Y" harness and repeat the test.

Until I know the rating of the BEC and the total load, (number of servos and any other connections), I cannot advise further! I await your response.

Have fun!
OK 3A UBEC should be enough to power a good number of Servos that are stalled. Next thing to check is the actual temperature of the servos and the ESC when the problem occurs! be careful because if there is a fault then they may get quite hot!

Another thing occurred to me is that you need to make sure that your transmitter batteries are good also. On my iA6 I actually had forgot to replace the Tx batteries and everything in the plane eventually just locked up because the Tx effectively wasn't transmitting.

Let me know what you find if anything!

have fun!
I haven't noticed any heat from the ESCs or servos, and I have seen them melt themselves and light on fire. I replaced the batteries in my transmitter, as they were a little low, however both my airplane batteries are currently dead, so I'll do my best to reply tomorrow, as they need to charge. I super appreciate the help today and am grateful for your time.
Thanks again,
Santino
 

Hai-Lee

Old and Bold RC PILOT
#19
I haven't noticed any heat from the ESCs or servos, and I have seen them melt themselves and light on fire. I replaced the batteries in my transmitter, as they were a little low, however both my airplane batteries are currently dead, so I'll do my best to reply tomorrow, as they need to charge. I super appreciate the help today and am grateful for your time.
Thanks again,
Santino
No problems the problem will be identified and solved eventually. It is actually frustrating when this sort of issue arises but then we all suffer from them eventually!

have fun!
 
#20
OK 3A UBEC should be enough to power a good number of Servos that are stalled. Next thing to check is the actual temperature of the servos and the ESC when the problem occurs! be careful because if there is a fault then they may get quite hot!

Another thing occurred to me is that you need to make sure that your transmitter batteries are good also. On my iA6 I actually had forgot to replace the Tx batteries and everything in the plane eventually just locked up because the Tx effectively wasn't transmitting.

Let me know what you find if anything!

have fun!
I'm actually starting to think your other idea about power was right. In my previous troubleshooting tests, I would plug two normal servoes into channels 1 and 2 (simulating 1 servo for ailerons and one for elevator) however I just plugged another into channel 5 to test it out, and if they're all plugged in and I move the right stick around, I don't have many problems, but as soon as I start flipping the switch I bound to channel 5 as I move the right stick, everything goes nuts, just like the y-cable. To further test this, I plugged a servo into one end of the y cable, but not one in the other. Once again, no issues with 2 channels, but the same with three. If it is infact some sort of power issue, once again, what can I do to fix it?