AnthonyW

So,
I recently decided to convert to 2.4. I have a JR PCM10SXII, a couple of jets and a 1/5 scal P-47. Now I have been flying R/C for 30 years and some old habits never die.
I have always (from the old days) used amplified Y-Harnesses when using dual elevator, ailerons, flaps, nose wheel/rudder etc in most if not all of my planes. It is just something I have always done.
Well, I installed the 2.4 in my Maverick Pro and suddenly my elevators would not work. I traced it to the y-harness. I figured hey, the plane is 8 years old on occasion, things go bad. So I replaced it.

So I am Fentress, VA this weekend for a jet fly and I am speaking with a JR rep and mention in passing the y-harness was bad when I installed the 2.4.
He asked me
JR: "WAS THAT AN AMPLIFIED Y-HARNESS?
A: YES IT WAS.
JR: DO YOU HAVE ANY MORE IN THE PLANE?
A: YES, I HAVE 3 MORE IN THAT PLANE AND 5 IN THE TURBINE
JR: WE (JR REPS) WERE RECENTLY INFORMED THAT JR IS STARTING TO TRACE CRASHES BACK TO AMPLIFIED Y-HARNESSES AND RECOMMEND YOU DO NOT USE THEM.
A: OH REALLY, HOW COME THERE IS NO WARNING IN THE MANUALS, ALERT OR ANYTHING?

I checked with a second JR rep and Bob Violetts Peeps and confirmed that for some reason the 2.4ghz will eventually burn out an amplified Y-Harness. Dave & Pete Malchione confirmed and said they have not converted a couple of jets yet as they do not know what is burried in the plane.

Bottom line is:
DO NOT USE AMPLIFIED Y-HARNESSES WITH 2.4!

I WAS LUCKY ENOUGH TO HAVE HAD MY 72MHZ MODULE AND RECEIVERS WITH ME AND WAS ABLE TO FLY ALL WEEKEND WITHOUT AN ISSUE.

I now have to go an purchase about 15-20 non-amplified y-harnesses and/or matchboxes. It just ticked me off there has been no alerts posted about this issue with 2.4. This could be a serious problem without the knowledge of an issue.

Just FYI for those of you that did not know about this.
Anthony

AndyAndrews

I never them in the first place. Just another failure point in my book. I would rather use a power expander for long servo leads. but that is really interesting news. Thanks for sharing it. Just confirms my feeling that those are dangerous to begin with.

I have had several just die for no apparent reason. Since then I never use them.

causeitflies

I stopped using them about 15 years ago...

Jet Lag

My Feedback: (26)

Anthony,If I remember right,amplified y-harnesses were only used with a certain type of JR PCM radio.Can't remember if it was Z modulation or S modulation.

bob1393

My Feedback: (10)

Anthony - this is not new information. If you have been following the threads here in RCU about 2.4, they have said amplifyers are not needed. You should not use chokes either on long leads. I have very long leads in my Elan, and after 32 flights have not had any problems.

Bob

DavidR

My Feedback: (1)

It was the Z-PCM that the amplified Y-harnesses were for. Anthony you really want to change them out anyway, the amplified dd not have the heavier guage wire.

DR

Gordon Mc

My Feedback: (11)

There's quite a BIG difference though, between "not needed" and "not recommended".

AnthonyW

Bob1393,
First, I should not have to read a 2.4 post that goes on for months and months to determine if it is "not recommended" or "not Needed". JR / Spectrum should have an insert placed into every 2.4 Reciever, Radio or Module warning not to use amplified y-harnesses with 2.4.

Attached is a photo from Horizon of the y-harnesses I have installed in 99% of my aircraft. Call it old school and unnecessary, but none the less, apparenlty there have been issues that actually cost people airplanes. There also no warning on the Y-harness packaging or website warning not to be used with...... http://www.horizonhobby.com/Products...ProdID=JRPA133
Do not get me wrong, I LOVE JR Radio's and "Feel the difference" everytime I fly.

I just want this to brought to the public's attention and hope JR will issue a bullitin ASAP.

I know there are enough JR Reps viewing these threads that can call Champaign, IL and talk to the peeps there to get something done.

Thanks
Anthony

cmjets

Hello:


But, the problem is for use amplified "Y" ?

If you use only "Y" withow amplified, you no have problems ?

I am thinking in change to 2.4, and in my jets a have a pair of amplified "Y". I need change the amplified "Y" for normal "Y" ???

Regards from Spain.

Carlos.
______________________________________

http://cmjets.blogspot.com/

yeahbaby

My Feedback: (21)

Anthony

luckily, like you, I discovered the same problems when switching over an older airplane and posted previously about my similar scenario. I originally thought it was a power issue since I was using a work bench pack but turned out to be the amp's extension as you discovered.

Thanks for reposting because it doesn't hurt to re-learn lessons from time to time and this one (like you mention) isn't really posted in the packaging anywhere.

rip 'em out, replace 'em and enjoy. nothing like the piece O' mind 2.4 provides.

cheers
buck

JohnVH

My Feedback: (38)

Interesting info, I just converted some planes to 2.4 and am working up the trust on smaller planes.. Im having radio issues in one, but to my knowledge no amplified anything in it... I get 'hits' with it, after a few days flying with nothing changed.. not sure what is up.

Synthetic

My Feedback: (18)

John,
What do you mean by "hits" on it?

Do you mean it is showing up as "fades" on the data log recorder? Or, do you mean you see "hits" taking place in the air?

Don

Helijet

How can 2.4 G be blamed for this??? My understanding of the technology is that the 2.4 is the link between the transmitter and the receiver. Once the processor in the receiver acquires and decodes the data it is sent to the servos. How can a lead amplified or not be influenced by a 2.4 wavelength??

There is one piece of the puzzle that has not been discussed and that is the the processor in the receiver. We know of the brown out effects, I can't help but wonder if this is another ( Gee....we did'nt think of that !!! ) one of those oops's. Too many changes all at once - we need to think through this carefully before making absolute assumptions guys.

D.W.

Gordon Mc

My Feedback: (11)

You seem to be ignoring all of the other differences between Spektrum and the 'regular' JR systems. The freq is not the only difference.

e.g. the problems previously reported with certain electronic sequencers etc had nothing to do with the freq either, but were instead caused by the different operating voltage at the RX.

gooseF22

the biggest problem I see is when people convert, they dont check their power system. If the voltage goes below 3.5 volts for any reason even for a few milli seconds, the receiver reboots. the newer ones recover quickly, but so far every problem I have personally traced down was an installation issue, except for one receiver that just went bad. It was an early 6100.

As you build your confidence, make sure your power systems are good and rated for the servos. Make sure the switch is good and the couplers are good. I saw a plane go in last weekend and it was dead when we got there. It looked like when a bird gets shot, it just froze and hit. I turned it over and the battery and radio tray was fully intact, but the power wire was hanging out slightly. thats all it took for the conversion to 2.4 to die. he blamed the radio until i pointed that out. I dont mean the systems are foolproof, but darn near everything I have personally seen is installation error. but thats just me.

thanks for bringing it to light about the amplifiers.

On your Y cords, keep them close to the receiver and run two wires back, and it will actually use less current overall.

JohnVH

My Feedback: (38)

well, odd as it is, hits like good ol 72mhz hits, plane twiches in the air and doesnt respond to my controls for a second, it also doesnt go into failsafe, so I dont know.. I noticed in the latest AMA mag that David Shulman switched to Futaba 2.4.. hmmm

Synthetic

My Feedback: (18)

That's interesting John. I wonder if anyone else has noticed this. I've gone into a hold before with my 2.4 but I for sure noticed it and it may have been for just a couple seconds but seemed like an hour when my jet was going "nose down" towards the ground before I regained control again and flew it back even though the turbine had shut down due to it going into a hold.

Don

noahb

My Feedback: (67)

John, by chance are you using any hitec servos? It's a long shot here, but a buddy of mine is running JR 2.4. On the bench without the engine running (gas airplane) it would sit still. When the engine was running, it would twitch. I asked him when the airplane was in the air, if the throttle glitched (diffrent servo) he said no, only the flight control surfaces which he had all hitec 985's I believe. He had some high end futaba digitals and put them in there and problem solved. I don't blame either JR or Hitec in this one as i would only be taking a guess.

Just a long shot.

Let us know if you find anything.

JohnVH

My Feedback: (38)

yeah, its very odd, as my failsafe is up elevators and idle throttle, and the plane rolled down and to the left... scary!

Yes, it has hitecs in it, I dont like hitecs, but I got it that way so Ive been flying it with them.. I guess time to get rid of them and see what happens.. I want to trust it! Been die hard JR fan for many years, so just need to figure this one out.

noahb

My Feedback: (67)

Well, at first he was running the two cell a123 cells. He then went with 5 cell pack and same thing. It was not the radio glitching but the servos acting up. Not sure why it would not do it when the engine was off, but once the engine started it would start to do it. He also had a hitec hs65 for throttle and it would not do it. Just all the control surfaces would do it. I don't think the radio was glitching, just something with the servos. He put futaba 9451's in and all was good.

are you running a 4 cell or 5 cell pack? I think he said when he went to 4 cell that it quit doing it. However, everything I fly has a 5 cell pack in it and I have never seen this.

Synthetic

My Feedback: (18)

John,
The problem I had with the lockout was not the fault of the 2.4 system. I have been using the 2.4 system in all my stuff from foamies to helis to turbines and other than the one time of the hold it has been flawless. All very low readings on the data log recorder and very few frame losses and no holds at all.

My problem when it went into hold I believe was caused from turning the receiver on too quickly after powering up the transmitter. Later I noticed when I did the same thing the led's inside the receiver did not "hook" up and I think I was not receiving the correct signal because I didn't wait a few seconds before turning the receiver on. The "hold" occurred when I flew further away than normal and it went into the hold for a few seconds and then control came back.

I have not done that since and have had no problems at all.

I for one...trust this system. Knowing someone can't "turn on" on me is worth it's weight in gold!
Don

JohnVH

My Feedback: (38)

So I need to turn this on in specific timing?

I dont trust mine enough to put into anything yet, I have it in a Gas Helicopter, and a couple other smaller (83" size) planes so far. No way Im putting this in my turbine yet.

Oh, the plane with the problem does have a 5 cell battery in it, but the odd part, is this was on the second day of flying it, like the 6th total flight for the setup since new..

noahb

My Feedback: (67)

Strange. Well, hope you get it figured out. I want to go to 2.4, but I am going to wait a bit. I know it's better then what I have now, but I would like for them to get all bugs worked out if in fact there is any left. I know someone can turn on at anytime and shoot me down, but I try and take extra measures to help prevent that. Time is not on my side on this issue.

I have two turbine jets and would hate to loose either one of them due to being shot down.

DavidR

My Feedback: (1)

I have not seen the need to do anything different when turning on. Turn on the transmitter then the reciever and go fly. EVERYTHING I own has been converted to 2.4 over the last year with the exception of my Phantom just because I can not do it all on 9 channels, this weekend it goes on 2.4 as well as my 12X will be here in the morning. I helped Tim Redelmen convert several large gas, and turbine jets to 2.4 last year before the WInimac meet, one of which was a large twin CItation that he flew WAY out and the link was solid. I installed it in a Bobcat two weeks ago and had the best range check and the most locked in feeling I have ever had with a Bobcat, flew it to the edges of my eye sight with out a problem. Proceed slowly if that is what makes you comfortable with the system but there are many people that have gone before you that have not had a lick of problems with it.

BTW I had problems with the old amplified Y harnesses several years ago before 2.4 ever came out. Have not used them in years. No matter what radio you choose to use it is still all about good setups. Mechanical, and electrical setups, get that right and you won't have problems with either 72 or 2.4 2.4 just eliminates one human issue the guy that turns on in the pits for just a second to retract his gear.....while you are on short final.

DR

Gary Jefferson

My Feedback: (167)

After I had my AR9000 receivers upgraded for the brownout protection I noticed the same thing with the lights flashing on the receivers when turning the receiver off and then back on...I have no idea what affect this has on range (or anything else) because everything still worked, but the solution is to turn the receiver off then turn off the transmitetr as well. Then turn them back on one more time. If you don't turn off the transmitter as well they stay flashing for some reason...Gary