Categories
Multicopter

Repairing an old broken DJI Phantom

I recently bought a cheap broken DJI Phantom 1 and would like to show you the process of analyzing and repairing the drone.

There were multiple problems, I will explain them one by one.

1. Phantom drops down when tilting

Problem

Here you can see that the phantom is hovering quite nice, but in the forward flight it suddenly falls down, all LEDs went off.

Cause

The Phantom has an internal USB cable which is connected to the microUSB port of the LED-module. This cable usually is hold in place by a cable tie and is accessible by the battery door.
In this phantom, someone removed that cable tie and the cable was flying around loosely, causing a short on the solder points of the battery connector or the power line for the speed controllers.

Solution

Fixed the cable with a cable tie. – Easy one…

2. Copter falls again midair

Problem

The Copter falls down while hovering, all LEDs stays on and starts beeping.

Cause

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The X3 connector from the PMU-board to the Naza is the power source for the flight controller. The red wire is the +5V line which has a loose connection on the board, although covered in the white protective glue.

Solution

I simply replaced the cable with a new one…

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  • OLYMPUS DIGITAL CAMERA

Easy to fix, hard to find.

3. Copter wobbels in ATTI mode – (really easy one)

Problem

When flying in ATTI-mode (Stabilized, without GPS), the copter starts to shake and wobble.

Cause

The previous owner changed the default board with the PMU-One for a zenmuse gimbal. The Naza (which contains the gyro sensors) is usually glued to the board with foam pads.
In this case, it was glued with superglue, wich won’t adhere to the coated PCB. So the Naza became loose and was just hold by the cables. I was impressed how stable it stays with this in GPS mode!

Solution

Fixed the Naza with foam tape.

4. Phantom randomly switches from GPS to ATTI mode

Problem

During a GPS flight, the LED randomly turns yellow for a few seconds and the copter starts drifting which means that it switched to ATTI mode.

Cause

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In the upper shell of the phantom is the GPS module which contains the antenna. To reduce interferences from the regulators, it is shielded with a rubber coated copper foil.
This foil was lacerated and the the copper foil wasn’t insulated on some parts. These touched the GPS module and randomly caused it to fail.

Solution

Just added some duct tape as insulation between the module and the copper foil.

Now, it seems to fly very stable and reliable. There are already further modifications queued…

Categories
Repair

Notebook repaired in Oven

I have a broken notebook (ASUS X5DAB) lying around and wanted to use some spare parts of it (Display, RAM, …).

The notebook turns the fans on but shows no image, neither on display nor on VGA.
That seams to be a common problem with this notebook due to bad solder connections on the graphics chip.

When I recently saw this article about resoldering a Macbook Pro in the oven, I taught that might be worth a try on the notebook.

So I started to disassemble the notebook:

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No I stripped the mainboard from all stickers and foils.
After that I formed some aluminium foil to a bed for the mainboard and put it in the (not preheated!) oven:

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The oven was set to 200°C, heating up takes about 6 minutes. After reaching the temperature, I left it on for further 7 minutes.

When the time was over, I turned the oven off and opened the for 2-3 cm to let it slowly cool down for about 30 minutes.

Then just quickly assembled (Display, CPU, RAM, Power) and … surprise: it works!!!

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The CPU still gets quite hot even when idle (what is not unusual for AMD Turion) so I think I should add some new thermal paste to the heat sink.

Although I have no clue on how long it keeps up, but for the moment it seems OK.