T9X ER9X Drift/endpoint issues

[jjreds]

Intermittent issue. THR and ELE are drifting around around the centers on the horizontal bar graph screen as well as the model servos. Problem appears/is worse when cold and bumping the TX amplifies the effect. I hsve torn it apart twice looking for bad solder joints and reseated all connectors several times. New Turnigy 9X recieved 2 weeks ago from HobbyPartz:
SmartieParts 2.2
HK Blue backlight
LiFe 3 cell @ ~9.6V
Flashed ER9X latest version (at the time)
Calibrated sticks and pots
FlySky w POS antenna wire
Located in NY, USA

This is my third 9X, I purchased this one for a friend who has it at the moment. He's lost all faith in me and today against my recommendation sprayed WD-40 in it. To be honest I'm not knowledgable enough nor do I have have adequate eyesight to deal with miniature electronics and PCB's. I have no problem to pay for a repair is anyone willing to look at it for me?

[Kilrah]

Try to (gently) twist the little circuit boards that are on the affected gimbal potentiometers, while watching the screen to see if it has an effect (jump even more or get more stable). Your pots are likely flaky, it's been the case with quite a number of radios shipped lately.

[jjreds]

ok Kilrah I'll give it a go when I get my hands on it and will let you know, thanks

[jjreds]

Moving the circuit boards attached to the pots has no effect. Moving all of the wiring connectors has no effect. Any idea what else could cause multiple channels to drift and lose calibration?

[ShowMaster]

Maybe swap a non drifting board into his tx if you have one, to isolate it to a board, case issue, or pots and wiring.

Also remove any mods you've added to restore it to stock, maybe re flash it to original 9x FW.

The real question is, did this happen when it was new and stock, or after work and flash wires were added?
In other words, was this added or did it come drifting?
Maybe pictures of the board and the added modifications. There could be cross talk from the added wiring?

Breaking it into a "was ok, and not ok",list will help narrow down what's going on.
SM



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[jjreds]

Well I thought the pots were ok but when the throttle stopped working I found if I put the pot in a slight bind it started working. I touched all of the connections with the iron, no luck. The THR and ELE pots are both bad and the other two are questionable (drifting @ center after calibration +/- 0.4-0.6). I'm a few days past the 30 and Hobbypartz says I'm stuck with it. I don't see how the gimbals/pots come apart........any advice appreciated.

This is a brand new radio, I added the SP board and backlight prior to first use, the problem arose while setting up the first model.

EDIT: Just found the post re gimbal/pot disassembly and repair. Going to give it a shot.

[jjreds]

Repaired [for now] used the instruction found here: http://www.rcgroups.com/forums/showpost ... count=3401

The ELE and THR pots were pretty easy to fix, $12 at the local auto parts, used the paint in the below repair kit:


I cleaned up the stringer after taking the below pic:


I want to replace these pots if anyone knows a source? I did open up a cheapo "Trustfire" TX (Flysky) w/ mechanical trims, the pots and shafts are larger and won't fit the 9X. Many thanks to the community for the great advise and assistance.

[edsimmons]

Hi,
I had a similar issue with the throttle stick on my 9xr pro. The problem I experienced was the yaw centre point would deviate from 1500us by as much as 50-75us when moving through the throttle travel. This was causing issues with disarming my flight controller with stick commands... also flying in huge arcs!

I looked at the small pcbs on the stick gimbals with the back off the tx, moving the sticks slowly I could see the pcbs moving slighty against the plastic of the stick. I decided to see if reducing the movement here would help, so I used a small amount of hot glue to stick the pcbs to the surrounding plastic.

I now have steady yaw midpoint all the way through the travel of the throttle and I'm once again very happy with my 9xr pro.

If you see any signs of this sort of stick crosstalk, fix it before it wears the potentiometer out!

I hope this helps someone...
Ed

[jhsa]

Repaired [for now] used the instruction found here: http://www.rcgroups.com/forums/showpost ... count=3401

The ELE and THR pots were pretty easy to fix, $12 at the local auto parts, used the paint in the below repair kit:


I cleaned up the stringer after taking the below pic:


I want to replace these pots if anyone knows a source? I did open up a cheapo "Trustfire" TX (Flysky) w/ mechanical trims, the pots and shafts are larger and won't fit the 9X. Many thanks to the community for the great advise and assistance.

You could get the Taranis radio's gimbals. They fit the 9x and are very good and cheap. I have them installed on all my 9x radios except for one, that I've replaced the pots with Hall sensors and magnets. It gave excellent results but not an easy mod to do.
My advice, Taranis gimbals. At about $15 a piece you can't go wrong..

João

[bob195558]

Your problem is a very old one and as João suggest the replacing the two gimbals with Taranis replacement Gimbals is maybe the best way to go.
I believe this problem may return at any time trying to use these very bad untrustworthy pots.
See here for more info: (viewtopic.php?f=95&t=2974).

Bob B.

[jhsa]

I gotta say, I have replaced mine but I never had a 9x pot going bad.. I have 4 radios and I flew my models a lot with two of them before I've upgraded the gimbals.. A lot means nearly everyday in the summer and once or twice a week average in winter. If the weather allowed, I was at the field..

João

[ShowMaster]

Several years ago I discovered that the 9X pots no longer had the silver conductive paint on the element to lead connection. Probably to save $?
Usually the bond what ever the connection was, was disturbed or broken when DIY work was done on the tx. The pot or boards were usually not well placed and "we" would move them a little during the mods to a better position. This movement of the pot boards put too much lead pressure on the pots and the element bond would open up.
The conductive paint was a fix, but in all the later pots, I would simply disassemble them, and with a fine needle nose pliers, re crimp the tiny rivet eyelet type contacts to the elements. A slight squeeze and I was good to go. No more moving the boards, and no more intermittent connection creep.
I actually was able to buy new sticks with pots and trim boards, 2x $5.00/set, from HobbyPartz. I emailed many 9x dealers and FLySky, asking if they sold 9X parts. HobbyPartx at the time contacted me and said yes, they could. I ordered "new" 2 sets (4) and 2 battery covers at the time.
Because my pot repairs worked, I still have the new spares. I did 10ea 9x conversions (er9x, ersky9x, 9xTreme) for me or local club members over the years. I've kept the parts as replacements for any one of us.
Now that the Taranis sticks are available for an option, that may be the better fix if your 9X is your most used tx.

Please detail your pot fix however, since many will like our options depending on the $ they want to spend on their 9x repair.
At the time the only drop in fix were Hitec sticks at $40-50 or fix the 9x pots, or go the Hall effect route.

I bought my 9x's for $39 each at the time due to a price war, so spending $40+ to fix one was hard to accept.
I had/have mostly FLySky brand with 3 HK brand. No antenna to cut off on the FLySky.

I'm now seeing more used Iris 9X tx for sale. The quad flies away, they want to sell the iris tx at a good price. I just bought a used one time Iris 9X tx for $40. Very clean when used one time ha ha!

[edsimmons]

I took the back off my 9xr pro and took a photo that hopefully shows the glue well enough for others to copy the modification. It's a really simple thing to do but it requires care to not stress the pots, make sure everything feels smooth in movement and correct any binding caused by the pot being incorrectly seated before gluing the pots to the surrounding plastic.

[bob195558]

I had tried stuff like this years ago with the 9x radio pots and it did not help as
the problem was with the poor construction of the 9x radio pots in the first place.
I hope it will work better for you.

There has been some people who have fitted replacement Taranis Gimbals in the 9XR-Pro radios.

There is also, some very good 9XR-Pro upgrade Gimbals which cost a lot (very high priced Gimbals):
(http://www.hobbyking.com/hobbyking/stor ... _39_s.html).
You can almost purchase a new 9XR-Pro for the cost of one of these Gimbals.

Bob B.

[edsimmons]

Hi Bob, I thought this may be the case with the T9X/ER9X but adding info here seemed the logical thing to do... I would hazard a guess and say that this may help in these radios if done before any issues with the pots appear. Play in moving parts should be fixed in a way that doesn't stress the pots, and should at least slow the deterioration of the pots... I particularly noicted that the wires on the throttle stick for the yaw pot were causing the board to slightly pivot on the back of the pot which would definitely cause the pot and connections to wear. Any potentiometer would suffer eventually in this arrangement!
Ed