Two lockout crashes with FrSky

[beau0090_99]

I don't want to pile on more bad topics, but I have just experienced two crashes due to lockouts of my Receivers. Here is the backstory...

Saturday, I flew my Sig 4star with the FrSky 8 ch receiver that I have had in it for a while. It worked great and I never had a problem. I range checked this about a month ago and do not range check them again. I then took up my second plane, a biplane and did not range check it prior to flying. I had range checked it about two weeks prior. The day I range checked it, I did have some issues with it, but i thought that it was just the "new" plane feeling and the fact that it was a bipe and I was not used to it. It seemed to not respond well in a certain part of the field as I approached landing. Well, shortly after taking off, I started losing control of the biplane. It was slow to respond and eventually it barrelled in to the forest (I am going to try to recover it tomorrow). I then remembered the problems I had been having with it.

The second plane that went in was yesterday. It was a small ducted fan jet that I had successfully flown about three weeks ago. I did not range check it, but it responded fine at most ranges with the 4 channel receiver. I recovered that and have the receiver in my posession. Tomorrow, when I retrieve the biplane, i plan on trying to range check a few of my receivers, those that gave me problems, and those that worked fine (I will pull out the 4star Rx and try it too.

Before both planes went in, I replace the case that came with the Tx module with the new one. In order to get the antenna into the hole in the back of the case, the small coaxial cable needed to be bent pretty sharply to make the corner. Do you think this might have caused a problem? Are there any recommendations for doing the range check, or anything to check with the Rx's?
Thanks,
Curtis

[RCModelReviews]

The transmitter antenna connects with a ULF connector which is very tricky to remove/replace without causing damage.

Did you disconnect/reconnect the cable that runs from the PC board to the antenna connector inside the module at any stage?

[beau0090_99]

I didn't. It still rotates freely.
The way i replaced the case is that I simply unscrewed the nut and washer from the outside of the old case, then I pushed the base of the antenna through the hole in the new case and secured it with the nut and washer. I didn't have to take the little ULF connector off of the board. I had considered it before getting the new case, but did not mess with it.
Anything else?
C

[RCModelReviews]

It's a bit hard to say but if the problem has affected multiple receivers then it's almost certainly something in the transmitter module -- perhaps the coax has broken inside -- I've seen that with other brands of transmitter modules -- but they all seem to use the same pigtail cable so I guess it could happen with any.

[Eva]

I don't want to pile on more bad topics, but I have just experienced two crashes due to lockouts of my Receivers. Here is the backstory...

Saturday, I flew my Sig 4star with the FrSky 8 ch receiver that I have had in it for a while. It worked great and I never had a problem. I range checked this about a month ago and do not range check them again. I then took up my second plane, a biplane and did not range check it prior to flying. I had range checked it about two weeks prior. The day I range checked it, I did have some issues with it, but i thought that it was just the "new" plane feeling and the fact that it was a bipe and I was not used to it. It seemed to not respond well in a certain part of the field as I approached landing. Well, shortly after taking off, I started losing control of the biplane. It was slow to respond and eventually it barrelled in to the forest (I am going to try to recover it tomorrow). I then remembered the problems I had been having with it.

The second plane that went in was yesterday. It was a small ducted fan jet that I had successfully flown about three weeks ago. I did not range check it, but it responded fine at most ranges with the 4 channel receiver. I recovered that and have the receiver in my posession. Tomorrow, when I retrieve the biplane, i plan on trying to range check a few of my receivers, those that gave me problems, and those that worked fine (I will pull out the 4star Rx and try it too.

Before both planes went in, I replace the case that came with the Tx module with the new one. In order to get the antenna into the hole in the back of the case, the small coaxial cable needed to be bent pretty sharply to make the corner. Do you think this might have caused a problem? Are there any recommendations for doing the range check, or anything to check with the Rx's?
Thanks,
Curtis

Dear Curtis,
According to your description, we suspect the coaxial cable had some problem. It is highly advised to check the cable carefully, especially the connected point with SAMA.
We are thinking of providing extra cases in which coaxial cable is fixed already by us for users' easy replacement. And we think this obviously will distribute convenience to you.

Should you have further thoughts and ideas, please feel free to let us know.
Many thanks!
Eva

[Eva]

I don't want to pile on more bad topics, but I have just experienced two crashes due to lockouts of my Receivers. Here is the backstory...

Saturday, I flew my Sig 4star with the FrSky 8 ch receiver that I have had in it for a while. It worked great and I never had a problem. I range checked this about a month ago and do not range check them again. I then took up my second plane, a biplane and did not range check it prior to flying. I had range checked it about two weeks prior. The day I range checked it, I did have some issues with it, but i thought that it was just the "new" plane feeling and the fact that it was a bipe and I was not used to it. It seemed to not respond well in a certain part of the field as I approached landing. Well, shortly after taking off, I started losing control of the biplane. It was slow to respond and eventually it barrelled in to the forest (I am going to try to recover it tomorrow). I then remembered the problems I had been having with it.

The second plane that went in was yesterday. It was a small ducted fan jet that I had successfully flown about three weeks ago. I did not range check it, but it responded fine at most ranges with the 4 channel receiver. I recovered that and have the receiver in my posession. Tomorrow, when I retrieve the biplane, i plan on trying to range check a few of my receivers, those that gave me problems, and those that worked fine (I will pull out the 4star Rx and try it too.

Before both planes went in, I replace the case that came with the Tx module with the new one. In order to get the antenna into the hole in the back of the case, the small coaxial cable needed to be bent pretty sharply to make the corner. Do you think this might have caused a problem? Are there any recommendations for doing the range check, or anything to check with the Rx's?
Thanks,
Curtis

Hi Curtis,
In addition to the last reply, I would like to check with you the following detail: which connection spots did you connect with the ULF connector on the board? If wrongly connected, problem will occur, too.
Regards!
Eva

[beau0090_99]

Thanks Bruce and Eva,
I really appreciate the extremely quick replies. As the ULF (I assume that is the little (maybe 2 mm diameter) connection on the PCB? I did not disconnect this connector, but I have rotated it. The point at which the cable was bent was near the larger (maybe 8-10 mm dia) connector where the hard plastic antenna connects. I have a few wireless routers laying around, if they have the ULF connectors on one end, should I try to plug it in in place of the cable that came with the module and try for range check? I also suspect the Tx module, which is disappointing, but if I can get to the bottom of it, I will be happy either way.
Thanks for your help,
Curtis
P.S. Even though I feel a little isolated being in the states, your quick replies help me appreciate your great customer support.

[Eva]

Thanks Bruce and Eva,
I really appreciate the extremely quick replies. As the ULF (I assume that is the little (maybe 2 mm diameter) connection on the PCB? I did not disconnect this connector, but I have rotated it. The point at which the cable was bent was near the larger (maybe 8-10 mm dia) connector where the hard plastic antenna connects. I have a few wireless routers laying around, if they have the ULF connectors on one end, should I try to plug it in in place of the cable that came with the module and try for range check? I also suspect the Tx module, which is disappointing, but if I can get to the bottom of it, I will be happy either way.
Thanks for your help,
Curtis
P.S. Even though I feel a little isolated being in the states, your quick replies help me appreciate your great customer support.

Dear Curtis,
We will send one coaxial cable and one TX module to you next week. Please replace the old coaxial cable in your TX module with the new one to check whether the problem can be fixed. If not, you can use the new module, and mail the old one to us. How do you think?
Curtis, please send an e-mail to me with your detailed address, for mailing purpose.

Many thanks and best regards!
Eva
Frsky Electronic Co., Ltd
Add: 100 Jinxi Road, Wuxi, Jiangsu, China
Mobile: +86-1358-5022-162
E-mail: evafrsky@gmail.com
MSN: liuyunjieeva@hotmail.com
Skype: evaliu0409
Website: www.frsky-rc.com

[Bingo]

I think "ULF" should be "UFL"
I have worked with hundreds of N type to ufl connectors and never had any issues, your problem could be related to the sharp bend in the coax or if the ufl connector was not crimped properly.

[beau0090_99]

Hi Eva,
I just sent you an email and I would appreciate a replacement Tx module and cable, just to play it safe.

I did do a reduced-range test on a couple of Rx's yesterday after retrieving my biplane from the swamp.

I tested 2-4channel Rx's. One was the Rx that crashed in my EDF jet, the other was one that has not flown. Both of them reacted the same way. When I had the Tx in reduced range mode, I walked away from the TX (using the servo test mode and setting the fail safe to full travel on one of the channels). When I got to about 350 feet (100 meters) they both locked out completely.

I tested 2-8 channel Rx's. One was a known good Rx and the other was the one I pulled out of the swamp in the biplane. I let it dry and decided to fire it up. I needed to rebind the Rx to the Tx, but it functioned mostly fine afterward. One thing I noticed is that one of the antennas was loose and fell off, when I split the case. I replaced it, but it was still quite loose and would come off without much trouble. When I pulled it out of the plane, it was secured to the Rx, but I was not sure of it's integrity. After testing both of these Rx's they both worked fine, but locked out at 350 feet like the 4ch. When I secured the antenna on the one 8ch, it worked that far, but without doing that, I had maybe 100 ft.

I have one of the older Tx modules with the older firmware for the reduced range check, but I am not sure what the range should be. I did not have time to do a full range check yet, but can later this weekend if I can find time.

Eva, would you still like to send me the Tx module and cable to test? I would like to have a side-by-side comparison if possible.

You can decide what you would like to do. Thank you for the help. I believe the Biplane crash was the bad antenna, and the EDF crash may have been bad antenna placement (behind a battery, or not straight - just laziness).
Thanks,
Curtis