GeneG

My Feedback: (11)

A few months back I bought 2 JR R770 PCM recievers from my local hobby store. I use them all the time so I didn't think anything about it at time.

The time came to put one in a Goldberg Ultimate. Setting the throws went fine and soon it was time to go to the field. I thought I was ready to go except that during my range check whenever I got more than 6ft from the plane with the antenna down I would lose all servo control. I tried everything I could think of but nothing helped. Full antenna up gave more more range of course but something was clearly wrong. So I packed up and went home to fix it.

I tried to change crystals but that did not help so I figured it was a bad receiver. Took the other new one out of the bag hooked it up and had the SAME PROBLEM! Took everything out of the plane, put it on the bench with a spare battery and servo hooked to it and still no go.

I tried everything I could think off. This drove me crazy for hours. As I sat there and stared at the receiver (could not think of anything else to try) and I noticed it was marked for 53Mhz!! I grabbed the bag from the new one I just opened and the bag was labeled for 72Mhz. I don't think by hobby store would have switched a 53Mhz receiver into a 72Mhz bag and since I got two of them a fluke is not likely.

Has this ever happened to anyone else? Was there somekind of screw up at Horizon or JR?

The scariest part is if I did not range check, I would have had enough range to taxi, take off and watch the Ultimate fly away![X(]

Square Nozzle

My Feedback: (1)

Gene, I'm surprised that you would get any response at all out of the receiver if it is actually on 53 mhz and you are transmitting on 72. Have you tried a range check with the system out of the plane? Could be something related to the receiver antenna routing. May even be the transmitter is acting up.

GeneG

My Feedback: (11)

Sure did. Took both receivers out and put them on a bench. Attached one servo to each (its a known good servo, just to be sure). Plugged a spare battery to one and then the other (one at a time) and got the same results.

I would not have thought I'g get anything either. I started to think that I was going crazy and checked my other R770s just to be sure they also did say 53Mhz, but they didn't. They had 72Mhz printed on the label.

As I started to play around I realized that I could get the server arm to move about 10 degrees just by moving the antenna right next to teh receiver. As I moved it back an inch or two the servo arm would slowly move back to neutral.

I think this is nuts too. If it didn't happen to me I would just assume I'm some rookie making a rookie mistake and blaming it on the manufacturer. I don't blame you for being skepitcal.

It does clearly say 72Mhz on the bag and 53Mhz in the reciever though....

Is there a market for 53Mhz receivers? I don't think I can take them back because I bought them a few months ago.

GeneG

My Feedback: (11)

Oh, one more thing, I did flip on a model that already has an R770 in it and checked it out. I thought maybe my JR 9303 was dying. Howver that one worked fine.

delman

Contact Horizon by phone - my son ordered an fm receiver one time and the one he received was a 72 instead of 75 mhz in the package. They were quick to send the correct one before the other was even sent back. Just explain the situation and save the bags. Their response and service has been excellent to me and others I know who have used them. You might have to send them back first.

Square Nozzle

My Feedback: (1)

Gene, before you send it back to Horizon, what does the crystal indicate for frequency? Coupled with the marking on the receiver case, that should be proof positive that you are dealing with 53 vs 72.

GeneG

My Feedback: (11)

I bought the crystals separately from the receivers. My hobby store only sells the receivers without crystals. So I did buy some 72.810 (CH 51) crystals at the same time. Those were the crystals I put into the receivers. I don't have any crystals on the 53Mhz band. I did try a known good crystal with the same results.

So if we assume the receiver is on the 53Mhz, and just let me point out that the receivers are clearly labled 53Mhz on their labels, I had 72Mhz crystals in them.

Square Nozzle

My Feedback: (1)

As a freind on R/C Scale Builder said, "The thlot pickens". Your crystals are probably talking to the receiver but the receiver speaks a different language. First I'd go back to the hobby shop that sold the receivers. They should deal with Horizon. If that fails, then I'd call Horizon customer service and let them know there is trouble in paradise and the receivers are coming back.

GeneG

My Feedback: (11)

I'm going to go back to the hobby store and try to explain the situation. I just need to come up with a good answer to the Question: "Why did it take you two months to find this out!" [X(]

Thanks!

Square Nozzle

My Feedback: (1)

Just tell them you were drunk .