Strange behaviour after rough landing

Last night I “flew” into a cardboard box just a few inches off the ground, and now the heli is misbehaving in the strangest of ways. It wasn’t going very fast when it hit the box, and I’ve certainly had worse crashes. Now, when I connect the battery, one of three things happen:

1) The servos center themselves correctly, the board initializes, servos work fine, as I slowly apply throttle the motors have these short (less than 1 second) bursts of speed but still respond to the tx.

2) The servos center themselves correctly, the board initializes, servos work fine, but as soon as I touch the throttle both motors go full speed and the servos begin twitching and moving all over the place and the heli no longer responds to any tx signal.

3) The servos either spin to the extent of their range of travel and stay there, or they twitch continuously, the board initializes, both motors go full speed and the servos twich and move all over the place and does not respond to any tx signal.

The tx batteries are fully charged, the heli battery is fully charged and all of the wiring appears to be connected properly. I’m rather sad because I had just started being able to hover (tail-in) full battery packs (5-8 minutes). Does anyone have any idea what could be wrong?

Could be a damaged servo drawing the BEC current below that needed for the RX. You can check this by removing 1 servo at a time and re-trying.

Only thing I can think of just now. - Oh and possibly a damaged RX xtal?

Loz

I agree - I doubt it's a crystal problem as it wouldn't initialise otherwise. Try removing both servos and seeing if the problem goes away. If it does, put back one servo at a time and see if the problem re-appears.

Thanks! I'll try that tonight.

[dongle]

Damaged crystal does not necessarily mean it wont initialise. Dont rule this out just yet.

[Robdog007]

I agree with Dongle. I'd check the crystal first, since it's so easy to check.

Could be that the crystal is making contact while the heli is motionless, but when movement is introduced the vibrations cause problems.

I pulled out the crystal, looked it over, and nothing was scratched, dented or bent. Other than a visual inpection, is there a way to test a crystal?

[rdn1153]

I'd check into the crystal making good contact and/or damage to the Rx antenna as a couple of possibilities.

[pgoelz]

The fragile portion of the crystal is inside the can and not visible. Only way to check is to try it in another receiver or try another crystal in your receiver. And the IF filter in your receiver is also similarly fragile and could have been damaged.

When things go nuts, does the LED dim or go out?

My money is on a receiver problem.

Unfortunately I do not have another crystal.

When things go crazy, the LED does not dim or go out.

Something I just thought of, which may mean nothing, is that the heli impacted on the side opposite of the servos and crystal. I'll disconnect the servos as per direction above and report back tonight....