Syma X5C-1 Issue

A couple of months ago I did the switch mod, power mod, and added two modules (NFR24L01 and A7105) to a 7E. It works fine with all my quads except for a Syma X5C-1. The motors cut out for less than a second from time to time, usually while pitching, yawing and rolling at the same time. I thought it might be a flight controller issue so I swapped it out with a new one, but the problem remained. I hit RCGroups looking for an answer, and found others with the same issue, but they were using the stock transmitter. In some cases the problem was resolved with a motor change. The theory was that a single motor going out might draw too much current and could cause the flight controller to shut down all four motors momentarily. Rather than swapping out motors I ordered another BNF X5C-1, which arrived today. I took it out for a test flight and it’s doing the same thing as the first one. The motors cut out for probably less than a second and the copter drops a few inches to a foot while turning. It doesn’t matter if the copter is right in front of me or 50 meters away, so I doubt that it’s a signal strength issue. My Tarantula X6 uses the same module and it works just fine. I don't have a stock transmitter for testing, but I have the same problem with two X5Cs so it appears to be a transmitter issue.

Any ideas what might be going on? Model, hardware, and TX ini files are below.

Model.ini file

---

name=Syma X5C
mixermode=Advanced
icon=SYMA-X5C.BMP
[radio]
protocol=SymaX
num_channels=6
tx_power=100mW

[protocol_opts]
SymaX5C=Off

[channel1]
template=complex
[mixer]
src=AIL
dest=Ch1
switch=SW B0
curvetype=expo
points=15,15
[mixer]
src=AIL
dest=Ch1
switch=SW B1
scalar=50
curvetype=expo
points=35,35

[channel2]
template=complex
[mixer]
src=ELE
dest=Ch2
switch=SW B0
curvetype=expo
points=15,15
[mixer]
src=ELE
dest=Ch2
switch=SW B1
scalar=50
curvetype=expo
points=35,35

[channel3]
safetysw=HOLD1
safetyval=-116
template=complex
[mixer]
src=THR
dest=Ch3
scalar=125
usetrim=0

[channel4]
template=complex
[mixer]
src=RUD
dest=Ch4
switch=SW B0
curvetype=expo
points=15,15
[mixer]
src=RUD
dest=Ch4
switch=SW B1
scalar=90
curvetype=expo
points=30,30

[channel5]
template=simple
[mixer]
src=HOLD1
dest=Ch5

[trim1]
src=LEFT_V
pos=TRIMLV+
neg=TRIMLV-
[trim2]
src=RIGHT_V
pos=TRIMRV+
neg=TRIMRV-
[trim3]
src=LEFT_H
pos=TRIMLH+
neg=TRIMLH-
value=-1,0,0
[trim4]
src=RIGHT_H
pos=TRIMRH+
neg=TRIMRH-
value=-1,0,0
[timer1]
type=countdown
src=THR
resetsrc=HOLD1
time=480
[timer2]
src=Ch3
[safety]
Auto=min
[gui-128x64]
V-trim=59,10,1
H-trim=5,59,3
V-trim=65,10,2
H-trim=74,59,4
Small-box=2,22,Ch3
Small-box=2,40,Timer1
Model=75,20
Battery=102,1
Toggle=4,10,0,72,0,HOLD
Toggle=16,10,0,65,129,SW A
Toggle=28,10,0,64,128,SW B
Toggle=40,10,0,130,0,FMODE
TxPower=102,7
quickpage1=Channel monitor


Hardware.ini

---

;Only useful for transmitters with an after-market vibration motor
enable-haptic=1
;
;switch_types: 3x2, 3x1, 2x2
extra-switches= 3x2
;
;button_types: trim-all, trim-(left|right)-(up|down|both)
;May occur more than once if necessary.
;extra-buttons=
;
[modules]
; there is no need to enable the cyrf6936 module unless
; it is wired to an alternate port. It is Enabled automatically otherwise
; enable-cyrf6936 = B12
has_pa-cyrf6936 = 1
enable-a7105 = A13
has_pa-a7105 = 1
; enable-cc2500 = A14
; has_pa-cc2500 = 1
enable-nrf24l01 = A14
has_pa-nrf24l01 = 1
; enable-multimod = A13


TX.ini

---

current_model=1
language=0
music_shutdown=0
mode=2
brightness=5
contrast=5
volume=10
vibration=0
power_alarm=0
batt_alarm=4400
batt_critical=3900
batt_warning_interval=30
splash_delay=35
[calibrate1]
max=3880
min=331
zero=1885
[calibrate2]
max=3873
min=174
zero=2007
[calibrate3]
max=3896
min=121
zero=1963
[calibrate4]
max=3873
min=372
zero=1986
[autodimmer]
timer=30000
dimvalue=0
[countdowntimersettings]
prealerttime=30000
prealertinterval=10000
timeupinterval=10000
[telemetry]
temp=farenheit
length=feet

if it's happening with the stock tx as well as a devo i'd not be thinking it's a tx issue

HappyHarry wrote: if it's happening with the stock tx as well as a devo i'd not be thinking it's a tx issue

Unfortunately I don't have a stock transmitter for testing. Just two BNF Syma X5Cs. Others have reported a similar issue with the stock controller, but the behavior was not exactly the same as what I've experienced. The reported cut-outs were longer and the copters sometimes dropped from the sky, while mine are short and the copter drops from a few inches to a foot.or so. Since it's happening with two copters then I'm currently looking toward the transmitter as being the possible culprit.

well to test your power cutout threory try using a larger pack, I still can't see it being a tx issue, though it could be an rx/antenna issue as the placement on most quads is terrible at best

HappyHarry wrote: well to test your power cutout threory try using a larger pack, I still can't see it being a tx issue, though it could be an rx/antenna issue as the placement on most quads is terrible at best

The power cutout theory was from a Syma group and didn't involve the battery. The idea was that if one motor was defective and was drawing too much current from the flight controller then the flight controller would shut down all the motors to protect itself. I agree that it doesn't seem like a TX issue, but after two BNF X5Cs having the same problem then I had to consider it. I suppose that I could have received two defective copters, so my next move is to replace all the motors in one copter with new motors from a different manufacturer. I don't think it's an antenna placement issue since it can happen a few feet in front of me, and it doesn't seem to happen any more frequently at a distance. Also, when I replaced the flight controller in the first copter I paid attention to antenna placement.

Thanks for your suggestions.

i've never seen any of these cheap quads have current detection/protection, so if the f/c is rebooting due to high current draw as you think it's either a thermal or low voltage situation. and again plenty people use the syma protocol without issues, so I still think your looking in the wrong direction, unless your own tx is damaged

HappyHarry wrote: i've never seen any of these cheap quads have current detection/protection, so if the f/c is rebooting due to high current draw as you think it's either a thermal or low voltage situation. and again plenty people use the syma protocol without issues, so I still think your looking in the wrong direction, unless your own tx is damaged

Whether it's a design characteristic of the flight controller, or just the way it works by chance, it does appear to shut down all the motors when there's a problem with one. I've seen it myself with a Syma X1. It would fly for around 30 seconds and then drop to the ground. If I disconnected the battery and reconnected, then it would fly again. I swapped out the flight controller with a spare but the problem remained. Then I stared replacing the motors one by one until the problem was resolved. I've not experienced this with the X5C, but others on RCGroups have reported resolving a similar issue by replacing a motor. My current issue is a little different in that it cuts out for a very short period of time and then keep flying

As mentioned, my next step is to replace all the motors. Hopefully that will fix it. If not, then I have a 3 in 1 module in hand and I just ordered another Devo 7E which should be here in a couple of days, so I will eventually find the problem through the process of elimination.

I swapped out the motors and the problem persists. So that's two new BNFs that have displayed the same issue, and one has had both a flight controller and motor transplant. I used third party motors just in case Syma had a bad batch of motors floating around, but it made no difference.

So at this point I don't see how this can't be a transmitter issue. Guess I'll find out after my new 7E arrives and I get the 3 in 1 module installed.

I got the new 7E, installed a 3 in 1 module, and I have the same problem. So I’ve been through two X5Cs, some parts swaps, and two 7Es with different brands of modules, and the problem persists. At this point I can’t say if it’s a copter problem or a transmitter issue, but there’s nothing more I can do with either the copters or the transmitter. So I guess I either have to buy a stock Syma transmitter or replace the Syma flight controller with some other brand. That is, unless someone has a better suggestion. The X5C is my wife’s trainer and it’s a bit more challenging to learn when the copter keeps cutting out in the air.

I currently have two X5C-1s and they do not have any kind of issue with dropping or signal lose. I am using a DEVO 12s with the Deviation multi mod and a devo 7e with just the module installed.

I got an original Syma transmitter from Bangood and my X5Cs have the same cut out issue, so it's not a problem with my 7Es or Deviation. Seems odd that two X5Cs (well three if you count the controller and motor swap) have the same defect when nobody else has reported the issue. Looks like my only option is to replace the flight controller with something else.

is this happening no matter where you fly? or is it in the same area every time? as it may be external interference causing the issues

Good thought, but it happens regardless of where I fly. Even turned my cell phone off to make sure it wasn't causing the issue.

then I'm at a loss with this one bud, only suggestion I have is to replace the fcb as you mentioned. bg have a nice looking brushed f3 based fcb available here >> m.banggood.com/Micro-32bits-Brushed-Flig...Frame-p-1070068.html I can't say how it performs yet as my one has only just changed from pre-order to shipped in the last few days. or you could go for an fcb that's compatable with silverxxx's awesome firmware instead

Thanks for the link Harry. I wasn’t aware of that board. I’ve been looking at a Micro Scisky brushed controller but I’m not sure if it will handle a larger copter like the X5C. The only builds I can find are micros and no information about larger brushed copters. The Micro Scisky is said to provide 3.4 amps per motor continuous, with a max current of 5 amps for 5 seconds. I don’t know the current draw of the Syma motors, but it seems reasonable that 3.4 amps would cover it.

The controller you linked to simply states “operating current of up to 10A or more”, but they are not specific about current per motor or continuous current. Don’t know if it’s more capable than the Micro Scisky or not. Nice that it’s cheaper than the Scisky, but then you have to add your own receiver which adds bulk, weight, and cost which could be significant depending on the receiver you choose. Being an F3 board it has the potential for better performance, but that would be wasted on a docile X5C. I’ll have to ponder for a while and decide which one to get.

I've just bought a bnf x5 and it works fine with my 7e+nrf but previously I've had some problems with voltage sag using the cheap small batteries that typically come with toy quads. I'd suggest trying a turnigy battery but I'll admit this is clutching at straws.
As a cheap flight controller replacement, I can recommend silverxxx's firmware. I bought a few h8 mini's for around 10$ each that I've used to practice acro mode with. My x5 is for use as a donor for one of these although I've not had time for the transplant yet. You will need to tune your own pids but there's plenty of help on the rcgroups forum.