Can't trust my radio :-(

[jhsa]

The title might seem a bit dramatic, but the fact is I got lucky today. Veeery lucky..
Well, the story starts with me repairing my easystar plane that crashed at the end of the season last year, due to a bad Elevator servo.. I couldn't even turn it by hand so stuck it was.. need to open it an see what is going on. but anyway, repaired the plane, new servo, took it outside without wings and me and my Son we were just driving the plane around for some good 20 minutes. All good. put the wings on it, and tested everything as i wanted to go to the field late afternoon to test fly it. Wind normally drops by that time.. All checked ok, removed wings, ready to go..
Then I remembered that i had another plane that just needed to change a broken prop.
Repaired it and proceeded to bind the plane to the radio. But before I realized I didn't have the model on the 9XT radio. so connected to the PC, downloaded the eeprom, opened the saved eeprom from my 9XR-PRO, and copied the model to my 9XT eeprom. Burnt it back to the radio.
Next bound the plane to my DJT module installed on the 9xtreme radio.
decided to activate the Brake on the ESC, and this is where it started to get weird. turned the radio ON, turned the plane ON, and immediately all servos went slowly to one side, and wanted to go even further. turned everything OFF, ON again, and the same thing happened. Then, next time or two it worked but sometimes the servos would jump.. I thought I had a bad RX (D6FR).
To find out where the problem was, I connected the plane I just tested before.. BANG, servos to one side again, this time on another model. So, the problem is the radio.. If I hit the back of the radio with my hands, the servos on the model would start jumping..
Put the DJT on my 9XR-PRO, and it worked fine. So i took my PRO to the field instead and flew without problems.
When I came back, decided to investigate further. Connected a couple servos to a receiver, turned tx ON, and started hitting the back of the radio with my hand.. servos started jumping. Connected the radio to the sim via USB, hit the back of the radio, no problem, no jumps..
Opened the tx, to try to find out where the problem is, but then, it stopped doing the problem.
So, here i am with a problem that doesn't show anymore just waiting for when I take a model to the air to bring it daown very quickly. Can't fix a problem that i can't find and also can't trust the radio until i find the problem and fix it.
So, my question is, what could make the servos go to one side slowly ( around 2 seconds), and get stuck in there??
If I get an answer for this question, it might take me to the cause of the problem..
I really wanted to make this my main radio. I think I got really lucky as the problem happened on the bench.If I didn't decide to change the prop on the other model, I guess I would have now new repaired broken model..

Thanks for your ideas

João

[MikeB]

If/when the problem shows up, check the values on the DIAGANA screen and see if they are following the sticks, or slowly drifting to one extreme.

Mike.

[jhsa]

Thanks for your reply Mike. Will do that as soon as it does again. but found another problem. Not sure if related but it could be.
I have noticed the radio rebooting. Boot reason, UNEXPECTED SHUTTDOWN, number zero..
So, started moving the back of the radio, with both halves separated but connected, and could get reboots. I'm replacing the back with the one from another 9x to find out if the problem is on the back half or the 9xtreme.. I think it is a wire. Probably the battery + on the 12 way connector..
Will check. and report.

Thanks

João

[Daedalus66]

Good luck with your trouble shooting. Rebooting is easily linked to a bad contact or wire, but what mechanism explains the servos going slowly to one side?

[lancaster]

Joao

Just a comment - might not help
I switched on the wrong module to my plane today and instead of no result, one servo went slowly to full throw - might give you an idea?

regards
Hans

[jhsa]

This is a frsky DJT connected to a frsky D8R..

Mike, servos were just going full throw.. The problem doesn't show in the ANA screen. I guess this is some bad connection. But it is being difficult to find where. It could also be a short somewhere...

João

[MikeB]

OK, so we have:
1. The DIAGANA screen showing the sticks are being read correctly.
2. The servos going slowly to an extreme.
What are the bars/numbers on the main screen doing? The same as the servos or following the sticks?

Mike.

[jhsa]

Ok, it seems the radio has at least 2 different problems. One seemed to be the battery plus wire on the 12 connector. I cut the wire close to the board and replaced it with another from another connector used on another project. That seems to have fxed the rebooting problem. It was bad connection. Still testing of course.
The other problem with the servos going full to one side is still there.
To answer Mike's question, the bars screen doesn't move when the servos jump and move to one side. It is difficult to recreate the problem. My guess is that there are more bad connections on the 12 way connector. Would a bad connection on the PPM pin cause this behavior?
I think I'd better order another 12 way connector and replace the one on the radio. This radio is 6 years old. It was my first 9x radio and suffered many mods. That connector was inserted/removed many times. Here is a picture of the reboot culprit

[MikeB]

Is the receiver going into failsafe?

Mike.

[jhsa]

No, failsafe is not programmed. I bound it to the radio yesterday and didn't set the failsafe, so I think if link was lost the receiver would keep the last position received?? I have just ordered some 12 pin 2.0mm pitch connectors.
I connected the back of my skyboard radio and I couldn't make it happen. maybe i didn't try hard enough.
it's amazing that I have trusted that radio for 6 years, and now this problem makes me think twice before using it again

I am also seriously thinking about soldering the wires to the connector instead of the original crimped ones. Maybe just add a dab of solder where the wire is crimped.
On other hand, the problem might very well be the little metal connector itself. I wonder if the male pins used on the 9xtrme board 12 pin connector could be thinner than the original pins?
I will also measure it..
I'm of to the field now with my trusty 9XR-PRO.
Thanks for your help Mike.. And Hans..
João

[KAL]

Hi João,
I would be careful with soldering crimped connectors where the wires are often bent.
The wires tend to break where the solder ends ...
Big Brother Murphy is watching you

Klaus

[jhsa]

I was saying about soldering them where they are actually crimped..

João

[KAL]

I noticed that.
But it's hard to control the solder flow ...

Klaus

[s_mack]

Soldering crimped connections is a common thing among hobbyists... but I agree with Klaus that it deserves caution. They aren't designed to be soldered. Professional manufacturing never solders them. It shouldn't be necessary or advantageous in any way *if* they were correctly assembled in the first place. That's why so many DIY solder them, is because they don't have access to the expensive crimp tools which are usually specific to the particular pin model.

For what its worth, I usually don't follow my own advice in this regard I usually hit them with a bit of solder because I often can't get a good crimp.

[jhsa]

In my case, I think the problem might be the metal female pin itself. After I've replaced it I connected it to the multimeter with 2 crocodile jaws and tried to make the connection with the wire fail. It didn't.
So either the problem is still there, or the problem was the connection between the 2 pins. I think it was the second option because the connection would fail, making the radio reboot, if I pulled the wire and the little pin moved inside the plastic..
I am now waiting for the slow boat that brings the 12 pin connectors I bought today, but might try a temporary fix of some sort for now..

João

[KAL]

João,
your problem brings an option to my mind that may be good to test connections with short interruptions.

In a former life as a (hobby) sound engineer I had a tool to check microphone cables.
You had to plug both sides of the cable into the tool.
For each core there was a LED that lit. With a toggle switch (reset) they were cleared.
The slightest interruption forced the corresponding LED to light up.

I think this could be implemented with a kind of (d-)flipflop used like a self-maintaining relais ...

Any remarks or suggestions?

Klaus

[bob195558]

Could be one or two wires in the process of breaking then could be the cause ?
Continuity check of the all the 12 pin wires and moving each wire around when checking continuity
may show something.

Bob B.

[jhsa]

I think in my case could be intermittent connection between the pins of the male and female connectors..

João

[lancaster]

Joao
I once had a problem with the silicon wires used on the lipo balance plugs

Pulling on the wire over a period of time had stretched the silicon and eventually fractured the wires inside

There was still an intermittent connection and also you could not see any damage on the outside of the wire

Just an idea
Hans

[Needhame]

It could very well be the connectors. Repeated removal and reinsertion can loosen the connector especially if it is a bit crooked and forced into place. I have had success tightening these back up by removing the metal part from the plastic connector then taking an exacto knife tip and pushing the little metal piece that acts as a spring in the logical direction that would create more tension on the pin when the connector is inserted.

I started having an issue a couple of days ago that is causing me some trust issues with my radio as well. The LCD has gone blank two or three times now. Once while in flight. I still had control of the aircraft but it was a bit unsettling. I haven't noticed if the back light was affected since I have it on a timer with button press activation and I have it so I can turn it on and off with the gear switch. I also don't know if any voice alarms were affected since I brought the plane down immediately and cycled power on the radio which fixed the problem. Each time this has occurred, cycling power on the radio fixed the issue. I haven't had a chance to check for loose connections yet but I will in the next couple of days. Has anyone else had this issue?

[Needhame]

Update. It did it again. The backlight comes on with the gear switch but button presses do not wake up the backlight. So it appears that the buttons are also unresponsive while the LCD is blank. I still have full control of the model. Well not sure if I have full control but the sticks work fine. Does anyone know which connectors these signals pass through or does this sound more serious than a loose connection issue?

[jhsa]

Is your radio the 9xtreme also?
It looks like there might be bad connection between the 9xtreme board pogo pins and the 9x mainboard.

Make sure the little pads on the 9x mainboard are flat (without solder) and clean.. you can clean them with alcohol and an old tooth brush.
Make sure the screws that secure the 9xtreme board are tight but not too tight.

João

[MikeB]

There is a high speed serial interface between the 9Xtreme and the original board that uses the pogo pins, one for sending the display information to the original board, and another for sending things like the buttons, some switches and the three pots to the 9Xtreme.
To allow for the possibility of a pogo pin failure, there is a secondary method, that uses a wire on the 12-way connector, for the original board to send this information. The 9Xtreme monitors the normal, high speed, serial input, and if no data is received it automatically uses the data from the secondary method.

Mike.

[Needhame]

Yes it is a 9xtreme. Since there is a backup communication path does that mean there may be something wrong with the 9xtreme board itself since the display and button usage doesn't come back until a power cycle? Or maybe I am misunderstanding what you are saying. Maybe something that is feeding power to that area of the board like one of the harnesses is causing the problem. Thanks for the responses guys. I will try to take it apart this evening to see if I can figure it out.

[MikeB]

What I was saying is you should continue to have control of you model, even if the display goes blank.
Note that the data transfer between the 9Xtreme and the original board is independent in each direction.
The buttons should continue to work as they are included in the backup data transfer.
It may be the original processor is stopping in some way.
If/when it happens again, see if you can tell if the three pots are still working and/or the THR or TRN switches are still working. These are all read by the original processor and passed to the 9Xtreme.

Mike.

[Needhame]

Thanks Mike. I took it apart. I didn't notice anything unusual. The pogos looked fine and seemed to have equal amounts of spring to them. The LCD went out once while I had it open but I didn't test the pots since it was a bit awkward. I reseated some connectors and cleaned the board and pogos with alcohol. The pads where the pogos go have some solder but it is factory solder only which is flat since I hadn't performed any mods related to them. So far it is working ok. I will respond back after I get a chance to use it for a while to see if the issue is resolved. Thanks again.

[don9f]

Hi, I have also witnessed the display going completely blank a few times.....the scenario was that I was part way through developing a mixer for crow braking on an electric powered glider, but was using the P1 pot to control the braking at the time, not the throttle stick, which was to come next. A few times whilst moving P1, the display went blank (remained illuminated as this was already switched on), the flaps no longer responded correctly and moved erratically whilst further manipulating P1, but the primary controls still responded normally.
I discontinued using P1 and changed crow braking to be controlled by the throttle stick and after thoroughly testing the controls ok, have now flown the glider successfully several times with no further problem.....P1 still not currently used.
This is the only aircraft that I have actually flown using the 9xtreme, all other model setups, mixes etc. have been bench testing only, so sorry I don't have much more info but from what I've just read, it does seem as this might be a similar problem?

Cheers Don

[jhsa]

Little update. My 12 way connectors finally arrived after one and a half month. I had already given up on them
So, I will try to bring my 9xtreme radio to a working state again. Of course, lots of testing needed before I even dream about flying a model with it.

João

[jhsa]

Replaced the 12 way connector on my 9xtreme radio.. It seems to be working. Moving the connector's wires now doesn't produce any reboot or loss of servo control. Hopefully it is fixed. Need more testing in order to be able to trust this radio again..

João

[jhsa]

Ok, been flying a little quad in the house with my 9xtreme radio.. It seems that replacing the 12 way connector and wires solved the problem.
will continue to test, but it looks promising for the summer

João