Hi all,
I was testing my APM 2 board and noticed it wasn't recognizing my receiver. To check if my receiver was working, I plugged an ESC directly into the receiver while the receiver was connected to the APM (looking back this might have been a bad idea) and the motor spun up as normal, but then the ESC started smoking. The ESC still works just fine, but it fried the voltage regulator on the 3DR radio. And now the APM board will not connect to a computer using USB or through the 3DR radio (luckily I have another 3DR radio that isn't fried). Does anyone know what could be wrong with the APM board and if it is fixable? I was looking at this thread http://diydrones.com/forum/topics/can-t-connect-to-apm2-or-upload-firmware?commentId=705844%3AComment%3A952949&xg_source=activity and figured I either have to flash the bootloader (and I have no idea how to do that) or I have fried the PPM encoder/usb to serial converter chip. Before I do anything drastic and really mess up the board, I'd like some input from smart people.
If it helps to know, my APM 2 is powered from the battery (w/ a regulator) through the input pins (where the receiver is connected). The ESCs I am using are Turnigy Trust 45A w/ a BEC (the ESCs are not powering the board).
Thanks
-Dave
Replies
Dave, it (the radio system) will eventually have to work while connected to the APM so do not fear that exclusively. What I mean is before integrating an entire project, the sub-systems should be tested to satisfaction. First simplify, then test.
The good news is your APM sounds OK. It have been a simple case of a wiring error that caused the ESC smoke OR it could have been an ESC failure unrelated to anything.
Test to perform: If you have not already done so, load Mission Planner (MP) onto your PC and see if you can get the CLI (Command Line Interface) to respond. If it responds, your APM is probably fine (from a basic perspective).
I do not think the APM could source enough current into the ESC to cause it to smoke. This does not mean you cannot make a error and see it pass through the connectors. It can get very tricky around the connections to the APM depending on the wiring you are using. My approach was to use the 3DR cables and even with that, I still made a mistake of putting a connector referenced to the wrong end. No damage but it caused some head scratching for a day or so.
-=Doug
Wow, smoking ESC, that is a new one to me.
Please confirm you have APM2.0 and not APM2.5.
The best way to approach this problem is to break the system down and test the pieces one at a time.
Do you read electrical/electronic schematics? I ask because I use them extensively when applicable.
Is your APM2 OK? If connected to USB (only), do you have any leds (red, blue, yellow, etc?)
If Yes (leds OK), then the APM2 USB fuse is intact and the Vcc lines are probably OK. APM 2.x does NOT have an on-board regulator. The only protections are fuses and a 6V Zener diode (it crowbars/regulates any input over 6V).
If No (leds not OK), you have probably opened the USB fuse at the least or possibly have a shorted component on the Vcc line.
Check above first before proceeding with more APM checks.
What kind of aircraft is this in?
You can check your radio gear totally separate from the aircraft and APM. Do so on the bench, completely isolated from your aircraft and APM wiring.
-=Doug