Bent gimbal...

RichWest · Jun 11, 2019

From two afflicted boards. Using the letter "D" as being Right orientation...and the orientation is biased to the pot housing rather than the board's X axis.

Board 1

Right
l l l
1.9 6.1
Left
l l l
6.0 2.1
Down
l l l
4.2 4.1
Up
l l l
5.4M 2.8M

Board 2
Right
l l l
2.1 6.7
Left
l l l
6.4 2.3
Down
l l l
4.7 4.6
Up
l l l
5.1M 2.8M

I've got no clue what the above means, so feel free to fill in your observation...

sirminder · Jun 11, 2019

RichWest said:
From two afflicted boards. Using the letter "D" as being Right orientation...and the orientation is biased to the pot housing rather than the board's X axis.

Board 1

Right
l l l
1.9 6.1
Left
l l l
6.0 2.1
Down
l l l
4.2 4.1
Up
l l l
5.4M 2.8M

Board 2
Right
l l l
2.1 6.7
Left
l l l
6.4 2.3
Down
l l l
4.7 4.6
Up
l l l
5.1M 2.8M

I've got no clue what the above means, so feel free to fill in your observation...

Thanks for the numbers Rich. I will take a look at my two boards and compare my results.

One thing to already note, is that yours are very consistent with one another...give or take a few ohms.

Maybe this is the key?

Fingers crossed...

RichWest · Jun 12, 2019

I failed to detail, readings were in K ohms unless noted and were rough readings. My test points were the three pins off the pot, center pin(s) being common.

Again I'm no electronics person, but yes the numbers indicate consistent reference to a given orientation...give or take. I think it would be ideal to trace this circuit to their output point and then measure. I wonder if there is a corresponding TP?

sirminder · Jun 12, 2019

What started out a "Bent Gimbal" thread is now starting to go in slightly different direction. However, I think we might be on to something...

I took reading of both boards, but I was not getting the similar results as you. Like your two boards, the readings on mine also came in close to one another. I was just a little confused about your example of the letter "D" and exactly which direction was which...sorry Rich.

So I used the following: When the Roll Board is mounted to the Roll Arm and this Arm is perpendicular to the Yaw Arm, the Flat side of the Pot's key hole is facing to the Right (backwards "D" and I think this is what you called Left?). It also did not matter how many times the Pot gets turned as the positions will always have the same values.

Roll Board B

Flat side facing Right
l l l
4.04 4.13
Flat side facing Down
l l l
6.02 1.98
Flat side facing Left
l l l
0.0 0.0 <------?????
Flat side facing Up
l l l
1.95 5.98

The fact that I was not getting anything when facing Left was weird and I could not understand how you at least got some resistance on ALL positions.

After a much closer look, I discovered that the 4th terminal of this Pot (right next to C45) had lifted! Perhaps this is why I was getting Zero when facing Left? I took a look at other Roll Board, and found that one too had the 4th terminal lifted! Any chance you can take a look at your boards again and check if this 4th Terminal is actually soldered down?

Here are the readings from the other board:

Roll Board A

Flat side facing Right
l l l
4.23 4.12
Flat side facing Down
l l l
6.07 1.97
Flat side facing Left
l l l
0.0 0.0 <------ again?????
Flat side facing Up
l l l
1.93 6.08

Can you remember what symptoms/problems the two Gimbals which, you took the two boards from, had?

Here's a picture of the 4th terminal from one of the Pots.

RichWest · Jun 12, 2019

IIRC, both the center pin and the 4th were the common and showed zero when metered between the two. I was getting a readings when off the 4th pin as the common when setting up, used the center pin thereafter. I only tested the yaw boards as they were handy. I'll review my findings using the 4th pin and find a roll board to test, just to confirm.

Typically of the four bad gimbals I have they were uncontrolled right to left pan. I think one or two was a drummer as well, its been a while since messing with them. And as you know now assembly is a process.

Again not an electronics person, so my descriptions are basic. The typical capital letter "D" is facing right in my mind, so that is the reference I used. Sorry for the confusion, was just getting comparison data for you. If you have a better descriptor, I'll change my ways....

It would be cool if this was the issue...

RichWest · Jun 12, 2019

All my Yaw boards checked out the same using the 4th pin as the common. No terminals lifted on any board. Did see a black film on the roll pot's terminals, rubbed off easy, likely aged flux residue.

ETA - My 4th pin on the roll board did appear odd. Closer inspection showed solder over the terminal...excessive solder.

Roll Board

Right
l l l
3.1 6.0
Left
l l l
6.6 2.0
Down
l l l
4.8 4.2
Up
l l l
0.0 0.0

And to be clear....

sirminder · Jun 13, 2019

Thanks for the feedback Rich.

I forgot to check continuity between the 4th and center pin. There also appears to be quite a bit of solder on the 4th pin on one of the boards. Perhaps this was a known issue and they slapped a bit more solder to prevent it from lifting?

Considering both of these Gimbals experienced a crash, that could explain the reason it lifted. I just can't explain why one them started to act up only after I straightened the Yaw Arm. Odd.

Moving on... Knowing that all your boards have the 4th pin soldered down, I will have to see about re-attaching these back down. I'm thinking exposing a bit of the trace and jumper it to the 4th pin.

RichWest · Jun 13, 2019

All the boards are multi-layer, so it is near impossible to trace a circuit. Having said that, maybe the 4th pin is a mechanical terminal rather than electrical... And, "Excessive" solder doesn't imply rework, just that it had more solder than what is typical.

There are a couple of chips that are static and moisture sensitive as packaged replacements. Not sure if this continues once installed on a board. But seeing how the Yaw board is exposed, could be a factor when handling the board during rework...again who knows. Conformal coating would have made sense for the yaw board either way.

Double check your Data/Power FFC termination. Since the pitch is so fine on the ribbon, there is potential for misalignment into its connector. I've done it...

I haven't seen a gimbal yet that was crash tolerant, regardless of brand or size. At least with the Solo gimbal there is some ability to repair, why I created this and other threads on the subject. Overall it performs well and takes a good amount of abuse, ymmv.

sirminder · Jun 13, 2019

Maybe its time I throw in the towel on this one....

I double checked everything on the Gimbal like you suggested and it seemed OK. Powered it up and it started to dance. I tried to help it keep balance and then the breathing Green light turned started to blink Orange. Also, I don't recall or noticed the GoPro turning on automatically, but now it does. Rebooted Solo and the amber light was still there for a while and then it started breathing Green and Dancing again.. For some reason, I thought a IMU calibration would help, but the movements of the dancing Gimbal prevented a successful calibration. I then changed parameters in Solex to Manual (or Indoor, I cant remember) and then reset them back to default. Rebooted Solo again and now all four Motor Pods were showing Green and could not connect to it....grrrr. I'm just making things worse. Removed the Gimbal and after a few reboots, the Solo seems fine now....I hope.

I do however, have plan B...

Storm32 Gimbal