[Hayabusa1]

we can buy a Z cpu and solder on it! what do you think? we need a special programmer for this or only upload the bootloader?

[TheOtherCliff]

Hey,

i have the same gps and a revo clone!

i have some Problems, my compass always rotates in the ins13 setting, and the board level is not correct in the gcs!

and when i try too fly the copter flys same lika a crap..

when i setting too basic i dont have this problem everything works correct!

i make all calaibrations same as descripted, with the accelerometer calibration i am not sure, the revo board in the picture looks different then my clone, and i am not sure how i must hold in what position

This sounds like a mag calibration issue.  You must calibrate the mag carefully, using OpLink, not USB.  It is recording the whole time!  Not just when you press the button!  So you must not set it down or put it close to metal the whole time you are calibrating.

[Mateusz]

we can buy a Z cpu and solder on it! what do you think? we need a special programmer for this or only upload the bootloader?

Maybe "ARM 2" is still fine! it's only "A" that is mentioned to have bugs that are not fixed. But if something is not right, it might be wrong caps, bad soldering or bad configuration/calibration, best is to test it, and I guess I would return to seller if I was not happy.

I have both original Revo and clone both fly just fine and had no issues with the clone yet. I am flying both with INS.

[TheOtherCliff]

Well, the GPS is very good, but the revo is crap. It uses the ARM2 version of the cpu instead of the Z-Version. It works well in complementary mode but acts totally random in EKF mode. the Amazon kit is from good luck buy

Next try

A friend bought one from thanksbuyer very early in these latest clones and I helped him get it flying.  It flies fine.  MainPort didn't work, and there was a small solder bridge on MainPort that I had to find and remove to make it perfect.

Working OK in CF, but not in EKF pretty much says it is mag chip (or mag calibration), and we have new code already written to use aux mag on GPS that should allow you to fly with EKF.

Try recalibrate mag using instructions in my most recent post. 

[TheOtherCliff]

I have 3 real OP Revo and they are all Z chip.  I have flown Z chip and it works.  I will look at friend's good clone Revo and post what it is if other than Z.

Anyone with clone Revo that works with EKF (INS13), please post here so we can know that it is not the CPU chip that causes the problem.

Edit: Friends Revo clone from thanksbuyer is also a Z and flies INS13 fine.

[a_morale]

The only problematic CPU is the one tagged with "A" as they are engineering samples.
They had a major flaw with "ART Accelerator" that is some kind of instruction cache, causing all sort of weirdness.
Probably there are not such devices around anymore, so it should not be an issues.

[cato]

As it seems that a 2-version of the CPU may work, I suspect that something could be wrong with the soldering. Another observation with that clone is that the BEC powering it gets very hot, so there could be a shortage somewhere on the board. I decided to put that revo clone on the bench, and when I have some time I will do a close check of the connections. I will report here if I find something.

[ggrif]

Just ordered one from here http://m.banggood.com/OpenPilot-CC3D-Revolution-Revo-10DOF-STM32F4-Flight-Controller-Staight-Pin-p-1000068.html?AID=12202217&PID=3836173&SID=iggw9ommjk0004o402ecu&source=affiliate&utm_source=Banggood_CJ&utm_medium=commission_junction&utm_campaign=OpenPilot&utm_content=sandy after reading at RCG that a couple of folks I have a lot of respect are flying it with something called Betaflight

Will report when I receive and test.

[cato]

I am not sure now if the failure I had was not caused by moisture on the board. I will test it again as soon as I have my new frame. I am talking to the people who built this board, contrary to many Chinese companies they seem to be open to talk, and it seems only one guy building this Amazon boards. I took a better look at the board, it looks actually nicely build, not the usual crappy soldering of some Chinese boards, everything neat and clean.

Will report as soon as the frame is built and tested, currenty still on it's way.

[TheOtherCliff]

In this kind of board, I wouldn't expect moisture to cause high current and thus overheated BEC.

[cato]

The hot BEC seems a problem of the BECs in Emax ESC. I found that they goet hot on 3S, but stay cool on 2S. Flying 3S only for a short while and never checked it before. But seems not fault of the controller, as it gets hot with 3S on original Revo too. What I was referring to was the totally uncontrollable behavior after a few minutes test flight. Actually it was moist outside, and although I checked for moisture I cannot exclude. Well, I will test it later on.

[TheOtherCliff]

I am hearing that you don't think there is a short in the FC any more.  A short would probably be easier to fix. 

For a given number of lipo cells, a linear BEC in an ESC should produce the same heat, regardless of the brand.  On the other hand, a given amount of heat coming from a small ESC will be hotter than from a big ESC.    30 watts heating your house.  30 watts heating a soldering iron.  30 watts delivered by the fine point of a laser.

The heat generated increases if you add lipo cells or draw a heavier load (current).

Assuming all your ESC's have all the servo wires intact, then usually, due to manufacturing tolerance, one or two BEC's (ESC's) on a quad sometimes shoulder most of the load and thus generate most of the heat.  I run 4s on 30A ESC's on my favorite quad (Revo, Rc Rx, GPS, Telemetry).  That is about as high as you want to go with linear BEC's.  The ESC's get good and warm, but not uncomfortable to hold.  They are out in the open, close to airflow.  I wouldn't want to put them inside arms.

[cato]

Thanks Cliff, for the explanations. I am not sure why it becomes so hot, but I will see how I can get that better. I am afraid that over long the ESC will not like it. My guess is that the temperature is between 40-50°C.

About the short, yes, I took a close look at the board, doesn't look like a short anywhere. Actually I think the soldering is pretty much o.k. So the behavior I had may have a different cause. As also the ARM2 seems to be no problem, moisture is one possible explanation. When I tested it the gras was wet, so the Revo or the ESCs could have catched some moisture. That happened to my Revo once. The sensors went crazy and I had to wait till it was dry again, and then do a full recalibration. On that Clone Revo I did not see  a problem with the sensors, so I will have to wait and check again. I won't put it in my 250 again, cause I simply want to fly from time to time, not always have it on the bench

Do I understand right, that you connect all your ESC's BECs to the revo?

[lichtl]

Hi,

I've also recently bought one of those. Initially flying on my Tri with LibrePilot went well (not sure if EKF was enabled). However while testing Taublabs and going back to LibrePilot I think I've bricked it somehow.

I've reflashed the Revo Bootloader with shorted Circuit via DFU-Util (tried as well to flash the entire flash). However my board just is somehow stuck in a reboot loop (I am able to get it into rescue mode) but I am unable to flash any firmware on it/erase it or at least it won't go back into normal mode.

If this is not related to this topic let me know and I will open a new one but I'm not sure if this might be related to the "clone" since I now tried OP/LP self compiled firmware/bootloader/entire flash.

[TheOtherCliff]

This is a known issue and I've already written up a way to unbrick Revo.
What version of TauLabs did you run?  Would you say that it was just a typical installation or was there anything unusual about it?
See this thread for unbricking instructions and let me know (in the unbricking thread) if something doesn't work or is unclear:
https://forum.librepilot.org/index.php?topic=208.0