Hi there all,

As I mentioned in different threads here regarding my H9's P51 Mustang PTS which came with JR's Rx R700 slimline receiver. Last year my mustang crashed, I put away the Rx cos it never responded after the crash. I consulted after a year with a senior who also works on receivers and fixed the old receivers, He told me that "IF" of that receiver got over-heated and burned. I dont know what is IF its internal frequency or what, but I wanna ask is it possible that Rx can get over-heated and burned? which causes a receiver to stop responding and naturally end result is a crash. Did anyone ever experience that. Thanks in advance for your advices and experiences.

Mody

I have been in this hobby for about 4 years and read the forums everyday. This is the first time I have heard about a Rx failing due to overheating. Based on my limited experience the only thing that I can think of that would cause that is a battery with excessive voltage being hooked to the receiver. Most receivers, today, will run either on 4.8 or 6.0 volt packs.

Maybe the cells in a battery pack somehow shorting together and causing a momentary overload of current.

armody, I would be very careful about using that Rx. I wouldn't put it in anything I valued. I use JR 700's in all of my planes. I like them and never had any trouble with any of them.

One other thing to check for is to make sure none of your wiring is cracked or nicked so that two wires could get together.

Thanks Safebet,

The battery pack I was using was original JR's 600 Mah Nicd with 4.8 volts. Wiring was factory fitted, naturally I would not take risk on that receiver again, as we are still waiting for that little device to change it and check it, if it starts responding, though flying it would be a risk, but if that incident never happened, I would still be flying my Mustang P51 PTS now. I missed that baby, and I still miss it very much.

Thanks again safebet, experience is short or long experience is experience and it has no short cuts.

Safe flying

Mody

The short answer? Apparently. During my buddy box training both my instructor and I experienced some weird and unpredictable elevator responses from my Goldberg Eagle 2. It would go from barely enough authority to land to huge overreactions causing straight up verticals. We changed transmitters, physical linkage and transmitter trims, and even switched servos out with no results. The behavior was intermittent and unpredictable. Since we had eliminated transmitters and servos as the issue, we were down to something in the crystals or the receiver or (less possibly) the receiver battery. The receiver was a Futaba 127DF and was new with the plane in July 2006. In November another member of the club loaned me a spare 127DF. We put it in with my old channel 22 crystal...and the problem disappeared. The plane became gentle and predictable. The receiver was under warranty so I sent it back to Futaba with an analysis of what we had done. While they did not tell me what their test of the receiver found, a couple of weeks later UPS delivered a New In Box 168DF from them with no charge (I think the 127 is no longer made). So while I can't 100% say a single channel on the receiver failed (perhaps through the connector or board), circumstantially both my instructor and I are fairly certain it did.

Dump the receiver. It isn't worth the lack of confidence you will have trying to use it again and not knowing for sure what is going on.

Vibration can kill your electronics, which is why we wrap up our receivers in latex foam rubber. The other likely possibility would be that your battery wasn't sufficiently charged.

My advice would be to send the receiver into Horizon Hobby, and have the JR service techs give it a look.

Theoretically, a receiver could overheat. It is a piece of electronics and heat is the enemy of all electronics. More realistically is that this "senior" follows the general rule of "If you can dazzle them with brillance, then baffle them with bullstuff". There are many things that can kill a reciever, but if it gave out in flight then it was more than likely caused by vibrations. Vibrations will kill a receiver quicker than just about anything else. As was said above, any receiver that is involved in a crash should be send in for service. No questions asked.

Ken

OK, in a RX "IF" stands for "Intermediate Frequency". Some RX use single IF's and others use dual IF's. Hence the terms single and dual conversion you hear about receivers. The "IF" section basically (but not exactly) changes the frequency inside the RX by mixing signals together. Don't worry about the technicalities, they're not important to most. Can an "IF" burn up? I've worked in electronics and/or a/c avionics for 40+ years now and have never heard of such a thing. I have seen "IF" circuitry fail to operate though.
As for a battery pack shorting out and causing a temp surge causing this to happen? The gentleman has a big bag of "Hooey" there. Can't happen. Even if there was somehow a current surge it wouldn't reach the IF sections.
Don't take your Receivers/Transmitters to the "good 'ol boy" down the street for repair if you like your stuff to work.
Sorry, I'm in my "be blunt" mood tonight.

Well,

Thank you all very much for your precious advices regarding this, Im gonna send this to the Horizon hobby people, Im sure they're gonna find out what could have been the real problem, but your feed backs did help me out a lot. I also have a practice to keep my receiver away from the vibrations in so I keep it in the rubber padding which comes with Electron 6 of Hitec and cover it with styrofoam so, it keeps it quite safe in it. I have one question more to you Bruce, I heard about Rx that negative shift and positive shift, what is the difference between both and how do they really work?

Thanks

Mody

The TX sends out a carrier frequency and the signal basically shifts 5 KHz either above or below that carrier during operation for North American systems. Some manufacturers chose to shift above and others chose to shift below. The RX will only recognize the correct shift it was designed for. PCM adds another ball of wax to the puzzle, more coding of the signal.
Basically any MFG FM TX that SHIFTS in the same direction as another MFG FM RX should work together. This can not be said for PCM.

There are a few RX out there that can be used with either shift, either automatically or through programming. There are also a couple of TX that can be set to transmit either shift.

Thanx bruce.

It really helped.


Mody

Basically any MFG FM TX that SHIFTS in the same direction as another MFG FM RX should work together.

Forgot to add the obvious part: IF on the same frequency.

I had a GB Tiger 400 parkflyer that I put a Norvel .074 in and I used double sided tape to stick the Rx to the fuse wall..it flew great for about 4 or 5 flights, then suddenly during its last flight, it did a figure 9 full throttle into the ground,,I'm pretty sure it was a vibration problem and dont do that anymore....as to sending in an Rx..last time I checked I think it was only about $10 more to buy a new Rx than to have one checked....I just buy new....Rog

Hobbico (Futaba) charges $15 to test a RX plus $9 for ship/handle and figure $6 to ship it to them for a total of $30 plus any repair charges.

A new R168DF from Tower is $60 plus shipping.

Almost forgot, since you're not getting it checked out get a new crystal too at @ $13