Just started having this problem with my GL300B controller that came with my Phantom Pro 3. FWIW, this was *not* after a firmware update, but was after leaving the controller sitting idle, uncharged, for 9+ months. I see the four blinking LEDs when I plug it in, but after unplugging I can't get it to turn on or show any sign of life. The battery is from 20151019, and did not swell. Intelligent Flight batteries that sat unused along with the controller had no problems charging.

Icer Posted at 2018-5-28 03:00
This is not software issue. In your RC is damaged 8pin voltage measurement IC chip CW2015CSAD. You can get it from ebay or alli. Cost few euro. If you have skills and equipment, you can reflow it by your selves. If not, then order part, bring RC with new part to any computer workshop and ask them to reflow component. It will be very cheap. On picture you can see RC board with already replaced component. I already fix "not charging" problem for many remotes.[view_image]

New fix. It is enough to remove this capacitor and RC charging fine.

fans9a437f7a Posted at 2018-5-13 12:54
I have the same issue

Here is my fix.
After 6 months on its box, not able to charge, one day before a important shooting!
I paid crazy price for a full cine Inspire 2 package to get let down !
I one dozen of camera and never had such possible issue and fix. I was very scared to try, but so many person said it can be fixed this way that I have tried anyways
Only option would have been to buy a new unit even if mine have only 20 charge cycle. This is ridiculous. Dead for dead I have tried.
https://www.visionrouge.net/web/ ... -wont-charge-fixed/
Spent an entire day fixing this, thanks DJI for making my life a nightmare; any compensation?

DJI-Paladin Posted at 2016-4-18 19:03
Hello, please make sure that the connectors are plugged in tightly[view_image][Image]

I too havevthis problem. My problem is new however. No problems last year, this spring, charged batteries, all good, then controller, no charge. On charger last night,  only two lights, charged for longest time then went dead like every other time. Usually only charges a few seconds then shuts down. If i unplug it and replug it in, onlybone light flashes. Discharges while on charger?  Bought second controller but it won't link with my drone. Yes, it's the proper model. Like to toss the whole thing in the dumpster about now.

DJI-Paladin Posted at 2016-4-18 19:03
Hello, please make sure that the connectors are plugged in tightly[view_image][Image]

I too havevthis problem. My problem is new however. No problems last year, this spring, charged batteries, all good, then controller, no charge. On charger last night,  only two lights, charged for longest time then went dead like every other time. Usually only charges a few seconds then shuts down. If i unplug it and replug it in, onlybone light flashes. Discharges while on charger?  Bought second controller but it won't link with my drone. Yes, it's the proper model. Like to toss the whole thing in the dumpster about now.

That's what you get for buying a Chinese product , that is CHINESE  vs an American or European product made there...