I will resume my problem and the solution:
My board is 2.5.2 (not original) and with firmware 2.9 works fine (or it appears to be but it is in danger).
After trying to update firmware from 2.9 to 3.0 or 3.0.1 the problem is the bad gyro health caused because of 5V on 3.3 regulator.
I am engineer so I unsold the 3.3 regulator and checked it. It was ok, but the 3.3v rail is at 5v, even without regulator soldered
Then I tried to replace the regulator for another one, same problem...
I tried to downgrade to firmware 2.9, the board works OK, so I tried to fly and it flies ok (or it apears to be OK, but all the sensors are overvoltage).
After 30-40 mins fly time the quad started to do some suddenly movements (I dont knew whats happening then, now I know it was the sensors at 5V instead of 3.3...)
But now I understand everything:
There is a problem in the board layout, there are a level shifter from 5V of the ATMEGA to 3.3v of the flash memory. The 3.3 and 5v references are inverted. Thats all the problem, nothing from regulators.
SOLUTION: Very hard and complex soldering skills. You must cut wires from the dataflash level shifter and interchange 3.3 and 5v. Cut the blue lines and replace with cable the red lines.
OR maybe you are not interested in use the dataflash but you want to repair your board: It is only necessary to cut the 2 wires in blue and the board will work perfect but the dataflash will appear as disconected.
It is incredible that all the sensors worked at 5v for so long time ago and didn't crashed :o. Also, the dataflash is working at 5V without problems... Incredible!!!
I didnt try to fly yet but the board loads the 3.0.2 firmware properly and passes all the tests.
EDITED LATER:
Mine is working with this change but the problem was the data lines and not the power lines of the level translator. You can check it in the datasheet of the chip.
So if you want to solve this the first thing you have to checkout it is if your pcb has the bad level routing on the dataflash. Definitive solution is very complex to routing but like me you can repair it.
Thanks everyone.
Replies
Nice to put a full report. But before making a report, sending mail to customers to warn them about the risks would have been better.
In such a case 3DR should ask customers to send back there boards and not fly with it.
This issue seems to be known since November and we are in March!
I hope that no one has been injured!
Vincent
I am getting more confused regarding the possible APM problem. Is this a concern for all of us, or a select few? The conversations are going all over the map. Randy had a video about the problem. Now, I can't tell if something is a potential issue, or what. but one thing seems to be certain, there may be a problem. ?? To what extent? Is this something that is going to create a crash?
I built, and have been flying my hexacopter using the APM 2.5, firmware 3.0.1 with the 3DR Power Module and haven't had any problem/s (7 months). - No smoke yet. :) I finished building a quadcopter using the APM 2.6, firmware 3.1 and 3DR Power Module, but I am waiting for better weather to do the compassmot. Should I be more concerned with the APM 2.6?
My main worry is if the problem will cause a crash? If so, should all APM's be grounded? Sounds crazy, but I'm getting more confused reading these discussions.
Re-direct me if I am off topic, but this page has got me spinning.
Thanks,
Dan
The issue is a technicality, if anyone finds a board with 5v on the 3.3v rail, with the reg removed, please PM me, and I will follow it up.
The issue on Guaifi's CLONE board may have been caused in many ways, but it is the ONLY report of this issue, so please, do not worry, there are tens of thousands of APM 2.5's/2.6's out there, both real and clones, it is not a problem for further flight.
Are there any schematics and layout files for an official 3DR APM 2.6? Sorry if this is an old and obvious question, I'm pretty new to this forum. Seems like a lot of EE's here, having those would help debug issues a lot better than reverse engineering a board to get schematics. The board layout issue indicated above would have been reflected in the netlist (I doubt CAD screwed that part up, unless they didn't check for rats before gerbering out, more likely an error in the schematics if findings above are true). Have I not looked hard enough or, more likely, is it proprietary? What about a clone board schematic? :)
thanks,
Andrew
The board layout and schematic diagram can be found on 3dr's website.
http://3drobotics.com/wp-content/uploads/2014/02/APM_v252_RELEASE.zip
Chose étrange : j'ai une carte apm2.5 de Hobbyking. Le temps de la transformer en 2.6, je m'aperçois qu'elle ne fonctionne pas. Gyro dead et des que je la bouge un peu je perds l'horizon.
J'étais pret á la beiner quand j'ai eu l'idée de mettre le firmware 3.0.1 - miracle tout fonctionne... faut que j'installe de compas externe mais elle semble bien vivante. Donc je ne vois pas la relation entre firmware, 3.3V et gyro cassé.
I get a apm 2.5 from hobbyking - dead with bad gyro. And the gyro seems to be dead. I put a old firmware - 2.9 and 3.0 - and the board seems to work well. I didnt install external compass but I do not get any warming. Then I do not understand relation between firmware, gyro, 3.3V.....
Vincent,there is very few "cases" with genuine 3DR boards as I understand
It does not matter however that it is wired wrong, as the chip can handle the 5v
That's not confusing, it costs a lot to make a new version, so it makes sense to wait till other changes are needed before fixing this.
This issue is not important, has no effect on flight, or safety.
With Vcca at 3.3v, is it problematic to send a 5v signal to the A pins of the level translator?
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