E011/E011c/BWhoop flight controller won’t bind

If you have an eachine E011 and E011c, or a Bwhoop flight controller that will no longer bind with your transmitters, it’s very likely that you have a bad crystal oscillator. The same would be true on a Betafpv Lite flight controller or any other flight controller that uses the Bayangtoys protocol.

Typically this will manifest itself after a hard crash but it could come from a fairly superficial crash as well.

Diagnosis:

Quad turns on when battery connected, blinks slowly for a moment and then rapidly flashes. TX won’t bind, nor will toy TX if you have one to test with. Quad doesn’t even appear to notice the bind attempts.

Solution:

“The Crystal” needs to be replaced. “The Crystal” is a 16Mhz crystal oscillator which is easily identified as on all the flight controllers I’m aware of, it’s the gray cylinder that always seems to be in the way on the top of the board.

You can order a new one, but the CHEAPEST way to do it is to take one from an unused toy transmitter if you have one laying around.

However, if you wish to salvage one from an unused bayang-portocol toy tx, you simply need to open it and locate the crystal in the transmitter. On the Bwhoop/E011 style TX, it’s typically located on the top portion of the transmitter’s circuit board. In any case, it looks exactly the same as the one on the flight controller.

The soldering and desoldering involved is a bit tricky. You’ll need a very fine tip and a steady hand. Some Kapton style tape could be very helpful if you have it around already, use it to protect the other small components near the crystal.

Keep in mind the crystal on both the TX and the RX are glued down lightly. When you desolder the TX, you’ll want to be extremely careful.

Soldering the crystal back on is an exercise in a steady hand. I highly recommend that when you do this, that you solder the crystal to the BOTTOM side of the PCB rather than back on top.

This will help you in mounting your camera in the future, but it’ll also protect the crystal from shock impacts that could break it in the future.

I use a pair of tweezers to hold the crystal and simply pre-tin the pads to re-attach the new crystal.

There is no “right way” or polarity to the crystal oscillator, so it doesn’t matter which way you solder it, just that the soldering is clean and you don’t bridge anything.