AQ died suddenly after succesful dynamic calibration

[kinderkram]

[leopold1]

What about sparking when connecting battery?

Mine went out like a candle when I armed the quad.

Version 2, yes.

[camflyer]

Hi kinderkram

Version 2, yes

Mine went out ca. 1 minute after connecting batt.

Ulrich

[JussiH]

I have a few questions to help me narrow it down...Please be honest, I will replace your MCU´s under warranty anyway!

I need absolute confirmation that you did not touch the boards when it happened. This is important in order to rule out human body discharge.

Was it a cold and dry day?

Did any of you have the boards mounted on metal standoffs or anything else that could cause connection from frame to board?

The only common denominator in all cases seems to be PPM Sum Receivers and reflashed OEM ESC´s. Is that correct?

If using a PPM sum converter or RX, you need to make sure its signal level is max 5V. STM32 is 5V tolerant on the I/O´s but I dont know how much overvoltage it will take, and its likely that a current spike on the PPM sum signal pin could be the cause - In another case of failing MCU, the user had his RX powered directly from the battery (some Hitec RX) and disconnected/reconnected the RX (while the RX was powered and the board was unpowered) and then the board did work on the next powerup and it has the exact same symptoms as described in your cases.

It may be a good idea to introduce a small resistor in the signal path to the board. But I am totally unfamiliar with PPM sum converters and RX´s, so I cant really say anything definate about it.

Did any of you have only the signal wires connected on the ESC, RX or any other peripheral, so that ground connection was relying only on battery ground?

[bn999]

[leopold1]

I need absolute confirmation that you did not touch the boards when it happened. This is important in order to rule out human body discharge.
My quad was sitting on the ground, batt plugged in and all leds flashing accordingly. I was arming the quad and and all went out. Thought is was the batt at firts so I reconnected it but same result. All the ESC's were also beeping very odd.

Was it a cold and dry day?
It was cold but humid but no rain.

Did any of you have the boards mounted on metal standoffs or anything else that could cause connection from frame to board?
I always mount my board with double sided tape or in this case nylon standoffs high enough from other electronic connections.

The only common denominator in all cases seems to be PPM Sum Receivers and reflashed OEM ESC´s. Is that correct? I used a 3DR ppm convertor as mentioned in AQ wiki and use flashed turnigy plush ESC's 30A with latest Simonk firmware.

If using a PPM sum converter or RX, you need to make sure its signal level is max 5V. STM32 is 5V tolerant on the I/O´s but I dont know how much overvoltage it will take, and its likely that a current spike on the PPM sum signal pin could be the cause - In another case of failing MCU, the user had his RX powered directly from the battery (some Hitec RX) and disconnected/reconnected the RX (while the RX was powered and the board was unpowered) and then the board did work on the next powerup and it has the exact same symptoms as described in your cases.
As mentioned above I used a 3DR convertor that was powered by the 5V coming from port 14 of the AQ board. I can not confirm nor deny if the PPM signal was 5V. Normally yes.

It may be a good idea to introduce a small resistor in the signal path to the board. But I am totally unfamiliar with PPM sum converters and RX´s, so I cant really say anything definate about it.

Did any of you have only the signal wires connected on the ESC, RX or any other peripheral, so that ground connection was relying only on battery ground?
ESC's were all connected as normal (gorund and signal). The 5V line coming from the ESC was pulled from the connector, just in case.

[camflyer]

Hi JussiH and bn999

It's very professional from you to ask these questions, so I will do my best to answer them correctly

I need absolute confirmation that you did not touch the boards when it happened. This is important in order to rule out human body discharge.
I was holding the Hexa on it's Carbon arms when it happend. Batt had been plugged more than a minute ago and SD-Card after the GPS-Fix less than a minute ago and all leds where flashing accordingly.

Was it a cold and dry day?
It was cold and dry, so no drops on the board.

Did any of you have the boards mounted on metal standoffs or anything else that could cause connection from frame to board?
I mounted the board on nylon standoffs high enough (some cm) from other electronic connections cause I wanted the compass have as far away from Motorlines than possible.

The only common denominator in all cases seems to be PPM Sum Receivers and reflashed OEM ESC´s. Is that correct?
Receiver was sumsignal JetiDuplex RMK2 with 2.4 GHz from Mikrokopter which gets his Power out of M14-Port. So I guess, the logical Signallevel is the same (probably 5V)

If using a PPM sum converter or RX, you need to make sure its signal level is max 5V. STM32 is 5V tolerant on the I/O´s but I dont know how much overvoltage it will take, and its likely that a current spike on the PPM sum signal pin could be the cause - In another case of failing MCU, the user had his RX powered directly from the battery (some Hitec RX) and disconnected/reconnected the RX (while the RX was powered and the board was unpowered) and then the board did work on the next powerup and it has the exact same symptoms as described in your cases.
As you explain here this is a bad idea - I would never do that.

Did any of you have only the signal wires connected on the ESC, RX or any other peripheral, so that ground connection was relying only on battery ground?
No ESC was connected as I wanted to check dynamic calibration. The only devices connected during the incident where the Jeti-Receiver powered by M14-Port and the 3DR Radio telemetry system 433Mhz powered via J3-Jumper.

Here is the log that recorded until the incident. Perhaps you guys see any strange issue.
https://dl.dropbox.com/u/46544184/Autoquad/009-AQL.LOG

Hope this helps
Ulrich

[leopold1]

So, I can conclude that my setup wasn't the cause of the defect?
Or did I miss something.
I forgot to mention that I also had an xbee hooked up also powered by the AQ board.

[JussiH]

No, its actualy very likely that a spike on your PPM RX was the cause, see explanation above from Bill. We will recommend that you place a small resistor (10-100R) in the signal path between RX and FC, and that you keep wires short and twist them around each other to keep the inductance low. You need to look at the signal level of the RX - it must not be over 5V.

But as I cant say 100 percent that it was caused by your RX, the boards will be repaired and returned to you under warranty. I will test all the boards here very carefully before they are returned. I am doing a session tonight, so I shoudl be able to return them to you soon.

Dry and Cold days are most prone to static electricity buildup - but I am very sure that this was not caused by static discharge - the most likely explanation is spikes on the PPM sum RX´s that was associated with all 4 reported cases of failing MCU´s.

[leopold1]

Ok, thx Jussi.
I hope this is the problem. Perhaps worth mentioning in the wiki for the PPM users.
Maybe I should step over to Spektrum or Sbus.
The new orange TX and RX from hobby king look promising.