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DX7 loss of control

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Old 05-15-2007, 09:03 AM
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ecoliburger
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Default DX7 loss of control

Lost an Aggressor recently starting to think it was the DX7. Anyone else flying a jet with 2.4 had a similar problem?
Following this thread

http://www.rcuniverse.com/forum/m_57..._1/key_/tm.htm
Old 05-15-2007, 09:26 AM
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Gordon Mc
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Default RE: DX7 loss of control

Thanks for the link - that's an interesting thread. I had to do a double-take on this one : http://www.horizonhobby.com/Products...ProdID=SPM1600 ...
Old 05-15-2007, 09:26 AM
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Default RE: DX7 loss of control

NM -
Old 05-15-2007, 09:36 AM
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Default RE: DX7 loss of control


ORIGINAL: Gordon Mc

Thanks for the link - that's an interesting thread. I had to do a double-take on this one : http://www.horizonhobby.com/Products...ProdID=SPM1600 ...

Me too!

From my days with big stereo equipment in the auto, we would install a huge capacitor that would hold enough juice to punch the subs through the windows if we wanted to, and it was always sitting there at the ready.

A 50 cent capacitor doing the same thing but of that size, you better not be holding the deflection long, cause that's not going to do much for long!
Old 05-15-2007, 09:38 AM
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Default RE: DX7 loss of control

Hi, i am useing the DX7 on a boomerang, and a 30% Extra with a zdz80. I have put many flights on both, and can only say that the radio has performed perfectly i use 6volts on both. I only use hitec 645mg servo's not the servos that came with the deal however after the bad reports about them. I have had trouble in the past with glittiching on my Futaba gear thats why i swapped over to the DX7.

Regards

Paul
Old 05-15-2007, 09:55 AM
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Default RE: DX7 loss of control

That Cap needs to be on the other end of the receiver voltage regulator....
Seems their PCB QC folks need to be fired.....

Go to the R/C car shop. They have ones for the electric cars using Supercaps of Farad proportions.
Old 05-15-2007, 10:40 AM
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Default RE: DX7 loss of control

When this cap is installed on the R7000, it will cause a huge inrush current at power turn on. This may not be an issue, but not sure yet. I am about to do some bench testing to duplicate the crash of my Gee Bee with a DX7..Will let you know my findings.

It was also relayed to me by horizon that the DX was never tested with a powerbox expander type product!!

One positive note is that, if this is "The problem", then at least we know how to fix it and we can enjoy the SS system!!!
Old 05-15-2007, 11:37 AM
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Default RE: DX7 loss of control

For what it's worth, we have a DX-7 on one of the JetMach demo planes with about 35 flights on it with no issues.

Using two 4.8 packs
Old 05-21-2007, 09:11 PM
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Default RE: DX7 loss of control

I posted the following to another DX7 thread today, regarding my loss of control. Any thoughts are appreciated.

I have been flying with a DX7 for several months. Today, with a fully charged battery, I took my first flight of the day and after several circuits around the field, with the Pulse XT trimmed out perfectly, the plane stopped responding and flew off in level flight toward a nearby highway. Fortunately it ran into an exit ramp embankment before it could hit a vehicle. After recovering the destroyed plane, I checked the 4.8 volt reciever battery and it read 5.18 Volts. I don't believe this is a battery issue.

Another issue I have noticed is that my Stic sometimes does not recognize the DX7 signal when I first turn the receiver on; requiring me to turn the receiver off and then turning it on a second time. This did not occur on the Pulse.

Another, probably unrelated issue occured with a new receiver I recently purchased which has one channel (aileron) which would not work.
Old 05-21-2007, 10:28 PM
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Default RE: DX7 loss of control

I have commented on the dx7 not registering the airplane when you turn on, and then turn the airplane off and on and it does several times in these forums. Never got an answer, but had 20 to 25 flights on a Eurofighter with it.

Last weekend I switched it out to 9 channel spektrum. Won't have results till I fly next, although I flew another Euro on the 9 channel system, and it was flawless.
Old 05-21-2007, 11:14 PM
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Default RE: DX7 loss of control


ORIGINAL: fx777

I posted the following to another DX7 thread today, regarding my loss of control. Any thoughts are appreciated.

I have been flying with a DX7 for several months. Today, with a fully charged battery, I took my first flight of the day and after several circuits around the field, with the Pulse XT trimmed out perfectly, the plane stopped responding and flew off in level flight toward a nearby highway. Fortunately it ran into an exit ramp embankment before it could hit a vehicle. After recovering the destroyed plane, I checked the 4.8 volt reciever battery and it read 5.18 Volts. I don't believe this is a battery issue.

Another issue I have noticed is that my Stic sometimes does not recognize the DX7 signal when I first turn the receiver on; requiring me to turn the receiver off and then turning it on a second time. This did not occur on the Pulse.

Another, probably unrelated issue occured with a new receiver I recently purchased which has one channel (aileron) which would not work.
Maybe it didn't find 2 clear channels and wasn't transmitting is why the RX didn't recognize the TX? Just because you turn on a Spektrum TX does not mean it actually transmits.

Dave

Dave

Dave
Old 05-22-2007, 08:11 PM
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Default RE: DX7 loss of control


ORIGINAL: rcguy!


ORIGINAL: fx777

I posted the following to another DX7 thread today, regarding my loss of control. Any thoughts are appreciated.

I have been flying with a DX7 for several months. Today, with a fully charged battery, I took my first flight of the day and after several circuits around the field, with the Pulse XT trimmed out perfectly, the plane stopped responding and flew off in level flight toward a nearby highway. Fortunately it ran into an exit ramp embankment before it could hit a vehicle. After recovering the destroyed plane, I checked the 4.8 volt reciever battery and it read 5.18 Volts. I don't believe this is a battery issue.

Another issue I have noticed is that my Stic sometimes does not recognize the DX7 signal when I first turn the receiver on; requiring me to turn the receiver off and then turning it on a second time. This did not occur on the Pulse.

Another, probably unrelated issue occured with a new receiver I recently purchased which has one channel (aileron) which would not work.
Maybe it didn't find 2 clear channels and wasn't transmitting is why the RX didn't recognize the TX? Just because you turn on a Spektrum TX does not mean it actually transmits.

Dave

Dave

Dave
Dave,

You are absolutely correct! Thank you.

Regards, Bill
Old 05-22-2007, 08:54 PM
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Default RE: DX7 loss of control

Sean, I have had a similar issue as you but realized I had my transmitter antenna setting right on the receiver and every time I turned on the transmitter I was not establishing a link. Sean this happen when I was setting up the receiver and servos in the plane, so I figured I was overloading the receiver. Could this have been your problem? Just food for thought.
Old 05-23-2007, 07:51 AM
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Default RE: DX7 loss of control

I can't see how a 4700uf 10v cap can fix a voltage dropping problem! I think they need look into these regulators that should have a simular cap on the output. So on the other hand the DSM system is not compatable with these regulators. And if its straight battery this cap is useless.
Old 05-23-2007, 12:34 PM
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Default RE: DX7 loss of control

What the cap will do is smooth out any rapid dips in voltage due to sudden and changing servo loads.
If the load were sustained then the cap would be no good at all.
Old 05-23-2007, 04:20 PM
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djindivik
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Default RE: DX7 loss of control

Would not 2 sets of RX cells in parallel & plugged into 2 separate channels via 2 switches, ('Y' leaded if necessary), do the same job ? I fly this system in my jets, although not on 2.4ghz, as a 'backup'. Ray.
Old 05-23-2007, 04:32 PM
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Default RE: DX7 loss of control

I believe the AR9000 RX has 2 battery inputs for this very same purpose.

Dave

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