AQ board suddenly dead. Help needed.

[LordPikaChu]

Hello everyone,

did my AQ just die? If so, why?

Last time I used the board was two weeks ago, it was working as expected. Today I powered it up and it seems to be dead (no LEDs, doesn't respond to radio commands, is not recognized by QGC), but it still gives power to my Rx and telemetry radio! The MCU is warm when power is connected.

The copter, on which the board is mounted, was sitting literally untouched for the past two weeks. What could be the cause of the board dying like that?

I would appreciate any insights.

[kinderkram]

That doesn´t sound good.
Possibly a damaged MCU, possible causes could be humidity, electrical discharge, voltage spikes or a weak part on the board.

Maybe some of our hardware experts can help to find the part in question...

[LordPikaChu]

Thanks for your reply. I don't think that the board has been subjected to any of these conditions.

Is it possible to buy an MCU and solder it to the board?

[LordPikaChu]

Okay, it looks like it's possible. Which one of these should I get?



And, more importantly, how can I check if this really is the MCU that is dead? I have a standard multimeter on my disposal.

[aBUGSworstnightmare]

[LordPikaChu]

[JussiH]

Mateusz,

You can send the board back and I will replace the MCU under warranty.

Thanks

Jussi

[LordPikaChu]

[joebar.rc]

There is a good change the 3.3V line is dead. Either the 3.3v LDO or the MCU. If you insist you could check the stm32f407 datasheet for the VDD line(s) and if that gets 3.3v. If not... well..
The dual output 3.3V LDO is sitting just above the capacitors and j3/j4
For the rest I dont have schematics so no further help possible.

[aBUGSworstnightmare]

Hi,
there are (many) ways to measure the 3.3V (+Vcc) rail:

1. Spektrum Sat connector (J7)
Pin1: +Vcc
Pin2: GND

2. Debug connector J6
Pin1: +Vcc
Pin3: GND

3. BOOT0 jumper
Pin1: +Vcc

4.. look at the 'AQ6 headers&connector docu' and search for 3.3V supply signals --> no schematic need in first place!

By the way: U3/U4 and U20 are 3.3V (+Vcc) LDOs:
U3/U20: LD2985BM33R
U4: MIC5210

Joerg
aBUGSworstnightmare