I have a quad copter with an APM 2.5 installed on it. Last week I updated from the stock 2.8.* code to the newest (available through mission planner) 2.9.1. Immediately after update, everything seemed fine, though I didn't try to fly it. I disconnected power, installed my gimbal (A11) and camera trigger (A9). When I reapplied power, I wasn't able to connect to it over the 3DR radios, so I tried the USB. Same thing. As a last resort, I tried connecting through USB in terminal mode.
Here is the overall list of symptoms:
Here's what I've tried:
None of that allows me to connect in configuration mode. Does anyone have any suggestions? Is the board just toast?
Was the quad flying/working on 2.8?
With APM2.5, are you using the 3DR Power Module to power the APM?
What was your power source for the gimbal and shutter servo?
And here I thought I'd given every piece of information possible :)
Just realized I left off one answer.
The camera was being triggered using the "relay" mode, even though there was no relay attached. This just sent +5V down a USB cable to a Canon PowerShot running CHDK. The S and - pins were used on A9.
I used the +/- power pins on A9 itself to power the servo (tilt mount only; it isn't near me right now so I'm not sure of the servo make/model). I just plugged the servo connection directly into that port.
Hmmm...that may have been a problem. THIS page on the adding the camera gimbal has this to say...
Warning:When using the APM Power Module or other dual supply setup with JP1 off, don't connect power from the A10 & A11 connector to the servos, just use the signal lines. Power the servos via PWM Outputs connector.
I would roll back to the previous configuration (I think that is what you were trying to do/did), no servo connected. In short take it all apart to the point where it was working so we can determine what is broken.
All the 'A' connectors are summed up for power distribution. This means that although you did not specifically connect power from A10 or 11, connecting to A9 was the same thing.
I will have to look over the schematic to see what may have given up electrically.
Do you have a very good inspection microscope or eye loops for tiny detail inspection?
I've been looking over the board layout (for APM2.5.2) and can not clearly see the +5 connection traces (even with all layers applied to the drawing. There was another warning about where not to connect the servos HERE.
WARNING:The diagram 'Typical QuadCopter Layout shows the gimbal servos connected and powered by the 5V coming from CH10/CH11. This will most likely cause a brownout. Please connect your servos for the gimbal to 5V/GND on the Outputs connectors and only connect the signal line to CH10/CH11 see AC2_Camera
The embedded link takes you to where I previously linked. The meaning seems be to use A0 - A7 (Pin 1 - 8) for power. A8 (pin 9) and A9 (pin 10) also are not clearly connected to +5VDC on the schematic; same for A10, A11.
This is a bit confusing, even to me, at this time.
I will go back to APM2.0 board for clues...
....nope, same connections though the JP name seems to have changed.
A search through the posts is probably in order but..in the mean time you need to get back to a working condition...if you haven't damaged your APM. Roll back the hardware/firmware to what worked and let us know.
I see the warning that you cited. Frustratingly, on the AC2_Camera page they show the gimbal's servo connected directly to A11.
As I mentioned previously, unplugging all of the external components (GPS, servos, motors, etc.) still doesn't change the behavior of the board. It comes up with a solid blue LED each time regardless. I suppose that drawing too much current from A11 could have burned something out, but that is substantially different than a brown out. Maybe a board replacement is in order.
If I shouldn't connect the servo directly to A11, where do I draw power? Is that what you are suggesting pins A0-A7 are for? Is there a harness somewhere that splits the power and signal wires allowing me to plug the servo's signal wire into A11 and power somewhere else?
Sorry if these are obvious questions. This is my first radio control craft that isn't a toy, so I'm really new to this.
After reading quite a bit, I think that I understand how you are supposed to connect the gimbal servo.
I've tested this on a backup APM 2.5 that I have and it seems to work. The quad shipped to me with power provided on both the output rails and the PM connection on the board and JP1 in place. It seems to me, the non-expert, that this should have provided ample current to the board since the two connections should be summed, but I'm willing to believe that isn't true. Removing JP1 should serve to isolate the servo from the APM and provide some additional protection.
I talked to uDrones customer service and they have generously offered to replace the board.
That is very kind of them.
I agree with your analysis above. Looking over the schematics and board layout all the way back to APM2.0 I still can not find trace connections for the +5 on the PWM Output lines - there are only 8, A0 - A7. A8 - A11 are the same situation, not clear as how it is connected on any layer of the board.
This may, or may not, be intentional on the designer's part. There is a name layer that indicated the center pins are +5 but without a clear trace, like seen on the Input connections, I can not be sure.
Here is a picture for show & tell (click on it for the full size):
Good luck and hopefully your experiences will be better and this one will help someone else.
What an interesting post. I have had 2 APMs die with the same exact symptoms you describe. It was during my first time setting up camera gimbals. I never connected the two events as what might have damaged the APMs. I started with a very small gimbal that had small servos on it. I ran it off the APM A10/11 both signal and power. No problems at all and gimbal worked fine.
I replaced that gimbal with a larger gimbal that had larger servos on it. Things didn't work right and that's when one of the APMs died. After searching around I read that it's better to power the servos externally. So I only have the signal wires on A10/11 now and I power the servos from a UBEC which gives a constant 5v out. It gets it power from the two wires that used to be connected to the APM before I removed J1 and added a power module to power the APM. Those two wires are connected directly to the power distribution board.
So, guess the lesson here is that it's not safe to power your gimbal servos off the A power rail even though that appears to be the logical place to plug them in.
Thanks for your post as it really bothered me that I had not figured out exactly what happened to my APMs. I spent a lot of time trying to recover them but like you I could flash them but I never could get them to boot again.
Glad they're going to replace it for you Nathan, I have a APM 2 board with the exact same symptoms, it's never had a servo plugged in anywhere and has only ever been connected through USB and yet the gyro is dead.
There quite a few reports of this and one solution is to replace a 3.3v regulator on the board, otherwise send it back (and they seem to accept ones with these symptoms them back very easily...)