ORIGINAL: pgitta
I sure hope someone can give me some advice on this one. I'm stumped. It's a long and confusing story and i'll try to be as clear as possible:
A couple years ago I bought a Futaba 6EXA package with Tx and Rx on channel 47. Worked great.
then...I wanted to try helis so I bought a Futaba 7CAP package which came with channel 50. Worked great, but since I had a couple other receivers using ch 47 already, I decided to swap the 6EXA's 47 and the 7CAP's 50 so now the 7CAP was on 47 and all was well.
Sold the 6EXA with ch 50.
(originally the 7CAP's freq.)
Hopefully you informed the person to whom you sold the 6EXA that you had ILLEGALLY changed the frequency so he could factor in the cost of sending it to an authorized technician for tuning.
Then last month the 7CAP s**t the bed and went dead and I had to send it in for warranty repair. Well, I didn't want to get into any hassles with the wrong crystal or battery or whatever coming back after the repair, so i removed them.
Got the radio back and went to find my ch 47 crystal that I was so worried about them losing or changing and now I can't remember where I put it!
Well, (told you, long story) while the 7CAP was being repaired and not knowing how long it would be, I wanted to still buzz around at lunch time with the SS so I bought a cheapo Futaba 4-ch package which came with ch 52.
I thought, no problem, just put the ch 52 Tx crystal from that radio in my 7CAP like I did before and swap the ch 47 Rx crystal with the new ch 52 one also and bingo, I'd be in action. Wrong. didn't have more than 2 feet range with the antenna down and maybe 20 feet up.
So I swear and curse Futaba for a bum repair but then decide to try something. I leave the ch 52 Tx crystal in the &CAP and put the ch 52 Rx crystal BACK in the receiver it came with (cheapo radio) and flew nearly out of sight after a range check, no problem.
So now I suspect my old receiver although it was working fine the last time I used it.
So I get another little park flyer Rx I had laying around and put the ch 52 it it and it seems to work, So I go out to the field, can't get the damn 4-stroke to fire, fuss with it all day, give up, come home, get it started and taxi around the neighborhood until I notice the engine surge intermittently when I'm about 40 yards away. I say wait a sec and check the range, and it's maybe 30 yards total.
GOOD thing the engine wouldn't start at the field!
So now I'm back to suspecting the 7CAP again and the repair but then why does it work fine with the new RX!?
these are all high freqs so what's the deal? Any ideas would be appreciated if you're still awake.
Here's mine, although I suspect you may not like it. You should not be swapping transmitter crystals. FCC regulation is that this should only be done by an authorized technician. It's not a Futaba issue, it's the FCC. When the transmitter crystal is changed the radio should be checked to confirm its output is correct. You never said what was wrong with it, but sending your 7CAP in for repairs WITHOUT the crystal and battery prevented the service center from testing two components that could possibly have caused the failure.