Im looking at a S900 with A2 to maybe buy it, its a bit hard to test it since the seller has no radio, so no radio is connected to the flight controller. When the A2 / S900 is powered on with the battery it makes a sound and the lights flashes a few times in different colors, which seem normal. But after that the LED flashes red fast for about 3 or 4 flashes and then it continues like that with 3 or 4 fast flashes at a time.


Is this normal when powered up without a radio if that makes any difference? Or does that indicate some problem, if yes what?
Is there a way to get a general idea that the A2 is working without having a radio connected to it? What to look for?
Also is the green and red lights under the motors on the arms of the S900 suppose to light up when a bettery is connected, or do they light up only after the motors are on?


Thanks for some answers.

The flashing red sounds normal to me during the time when the A2 is trying to establish a GPS position. If you're inside a building, you might ask him if you can't take it outside to a clear sky to make sure it can get a GPS lock.

On my system, the arm lights blink 3 times when you first connect the battery, then go out. I know that they are on when the platform is flying, so I assume they come on when the motors start, but I've never been underneath at start-up to witness it.

As for making sure the A2 is working, you might consider downloading the A2 Assistant from the DJI/PRODUCTS/CONTROLLERS/A2/DOWNLOADS page and hooking up a USB cable. That would enable you to make sure the IMU has or will calibrate, as well as look at things like the firmware versions

HMArnold.msn Posted at 2015-5-15 23:14
The flashing red sounds normal to me during the time when the A2 is trying to establish a GPS positi ...

Hi, thanks for the answer. I read later that three red blinks is normal when it tries to establish a fix like you said, but four blinks indicates a problem with the A2, if i have read it right?

Unfortunately i didn´t end up buying the S900 which is a shame since the price was very cheap, that was also the reason i was a bit suspicious, don't know if I'm right since when i wanted to return to the buyer and check the S900 /A2 more carefully according to your suggestions he started to come with a lot of different excuses that hindered me from doing the purchase and hindered me from coming and checking the drone more carefully.

Actually the first time i was there and checked only the gimbal, the gimbal made and constant incredibly loud "hacking" noise from one of its motors, he had told me that all works fine. Thats why i left, but then we decided on a lower price on email, but when i told him because of what happened to the gimbal i need to check the rest of the things very carefully he started to come with these excuses.
So i don't know what the deal was, but it was very cheap, 2450 USD for a S900 with A2 and with Light bridge and with a Zenmuse Z15 Gh4 gimbal and a Lumix Gh3 camera. After the gimbal problem we decided on the sum of 1800 USD, i thought that maybe i can fix the gimbal motor or change it.
I ended up buying another DJI drone, not that fancy as the S900 though.
Thanks for your answers anyway.