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Old Jan 21, 2012, 11:48 PM
Ribble is offline
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Crash and learn
United States, PA
Joined Dec 2011
2,852 Posts
michaeldepeza - Well there were several. Do a range check first.

First remove the transmitter antenna and walk away from the helicopter until the red LED under the canopy goes out. About 30 feet (I flew my DH9104 for the first two weeks with no transmitting antenna).

Put the transmitting antenna back in and keep on walking. I'm guessing range was about double. If you can't see the helicopter anymore, then your transmitter should be OK. If not I can help.

Next, wrap the helecopter receiving antenna back on the skid as it came out of the box. If you didn't unwrap it, then skip another range check. I found that the receiver was tuned for the antenna on the skid.

OK, now you have to decide if you really want to do this. The DH9104 receiver antenna is soldered to the Electronic Speed Control (ESC) board. Next to that is an upright coil with melted wax filling the hole. Underneath the wax is a movable ferrite slug that is threaded so turning it with a very small screwdriver moves the slug up and down inside the coil. Ideally it should be a non-metallic tuning wand, but I didn't know what was in there, so I put a jewelers screwdriver in from the bottom and pushed and turned.

If you never tuned a coil before, then I advise not doing it because you will likely damage the slug, the coil, or the ESC board itself. And the best way is to do it with the ESC connected to the battery and turned on.

However, since you will nuts it up anyway (I did), best to keep the battery disconnected (the switch only turns ON/OFF the +5 volts and the ESC board itself is hot at battery voltage).

So, you have to get the wax out of the coil somehow and after that you have to be able to adjust the slug. That done, you can tune the receiver.

Remove the antenna from the transmitter and set it flat. Walk away with the helicopter until the red LED goes out. Adjust the slug until the red LED comes back on. Walk farther and repeat. Etc.

Getting that far, try unwrapping the receiving antenna from the skid and tie it to the tail plastic part. Repeat the walk and adjust.

Again, if all this is Greek to you, then better not done. Good luck.
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