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Spektrum DX-7

Old 06-05-2007, 06:00 PM
  #2151  
rmh
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Default RE: Spektrum DX-7

Even tho it was not bound --correctly--
the book says:
bind to do setup then bind when completed
(also check for flap switch positions etc..)
It is all very easy - first read then read again .then try it then read again.
some of th book is flat ol vague , so if you read and test and compare -you will see 99% of the recommended methods for radio setup.
Personally, I would have written it differently but then everyone has their own interpretation of how to write a manual.
Old 06-05-2007, 07:02 PM
  #2152  
rino
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Default RE: Spektrum DX-7

All,

Anyone have an idea of what the expected failure rate of radio components are? For instance, if you buy any x brand rx at your LHS would you expect 1 in a 1000 to be bad or 1 in 10,000? I'm not fishing for a Spek bash here. I'm just wondering. The only rx I have ever had fail in 6 years of flying was an X brand PCM.

Thanks,

r
Old 06-05-2007, 07:49 PM
  #2153  
rmh
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Default RE: Spektrum DX-7

most failures are owner caused -
the incidence of failure in electronic products is extremely low -being waaaaay under 1% in most consumer stuff
Once the electronicss have been thru initial period of run -they typically will run forever
however th older stuff with lots of coils and and discrete parts -really did age and needed perking up from time to time
the basic design of the Spektrum RX is simply-a chip - this type technology has extremely ow incidence of failure -once setup (programmed) .
many failures(?) I have read about on the TX of the Spektrum are again owner induced -
Of all the Spektrums here - no failures.
The stuf on 72 --well again most dumb thumb stuff
Old 06-05-2007, 08:31 PM
  #2154  
Flypaper 2
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Default RE: Spektrum DX-7

The speaker crapped out on my trans. last week but not a big concern. Not woth sending in for a fix. Still the best thing since bubble gum.
Old 06-05-2007, 11:14 PM
  #2155  
Ed
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Default RE: Spektrum DX-7


ORIGINAL: BillS


There may only be 5% of my club that Spectrum could be recommended. The other 95% would be dangerous.

Bill
Excellent point Bill. After reading the last few pages of this thread, it would be difficult for me to now recommend the system to anyone inexperienced in basic battery management.

> Jim
Old 06-06-2007, 02:24 AM
  #2156  
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Default RE: Spektrum DX-7

Txs for your answer guy.

In fact one of my comments to this pilot , was that I was surprised by the electronic salad he fixed for his plane, here is a copy of what he installed:

3 Servos 8611 elevator & rudder
2 Servos hitec 5645mg ailerons
2 Switches JR heavy Duty
JR Matchbox for elevators
Battery 2700 mah Expert
Battery 4200 mah Hobbico Hydramax
Receptor DX7

Think this salad and bad binding could cause the crash?

Nice landings 2 all U.

Rafa
Old 06-06-2007, 03:10 AM
  #2157  
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Default RE: Spektrum DX-7

G'day Mate,
So he didn't have a throttle servo, why did he have a matchbox? He could have just plugged all the servos into the RX, I'm using 6 servos on my Katana, no problems & no need for a matchbox.
What voltage was the batteries? I assume 6 volt.
How did he supply power to the RX. What was the switch setup?
Did he check both batteries, under load?
Did he have both batteries switched on?
Old 06-06-2007, 10:02 AM
  #2158  
best_panther
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Default RE: Spektrum DX-7

HI Everyone,

I'm Richard And I had the problem with the Spektrum RAdio, Thanks to Alcarafa to Help me find what happened

I'm going to complete the list of electronics

3 Servos 8611 elevator & rudder
2 Servos hitec 5645mg ailerons
1 JR standard for Choke
1 Hitec Standard for Throttle
2 Switches JR heavy Duty
JR Matchbox for elevators
Battery 2700 mah Expert (ignition)
Battery 4200 mah Hobbico Hydramax (receiver and servos)
All of the extensions were Hitec heavy duty
RAdio and receiver DX7

The problem was this, I was flying my plane during 8 minutes, then I decide to landing, Making a long turn at mid alttitude to prepare to landing the plane just start to move the Rudder (not flutter) and the sticks never respond, In fact my dad was behind me and I have the time to show him the radio without moving anything and the plane moving the rudder dramatically. I had programmed the failsafe to Idle, and the engine never reduce the speed.

After the crash I check the rudder and it was in perfect condition, (the first thing I thaught was the rudder coming loose), then everything was OK the receiver never shut down and the battery was in perfect condition.

What happened??? I don't know!!!

Thanks.
Old 06-06-2007, 11:24 AM
  #2159  
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Default RE: Spektrum DX-7

Txs everyone for your help guys:

Like Richard I fly with DX7 but have never had any problems ata all with my radio nor reciever.

What happen to Richard is a true mistery and I guess we all would like to avoid something like this happening to us.

Hope you have some comments to help solve this.

Nice landings 2 all U.

Rafa
Old 06-06-2007, 02:11 PM
  #2160  
N429EM
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Default RE: Spektrum DX-7

The way I understand it, FailSafe will only engage if the rx loses communication with the tx.
If you're certain you have a catastrophic failure, but the rx doesn't respond with FailSafe settings,
you could probably turn off the tx. Of course, now you're guaranteed to have no control of the aircraft.

Just a suggestion.
Old 06-06-2007, 02:49 PM
  #2161  
rino
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Default RE: Spektrum DX-7

In any case you should probably correspond with Horizon. They need feedback on cases like these whether it's the radio system's fault or not.

I've found that emailing support sometimes works better than calling in. Of course, they will probably want to test your equipment.
Old 06-06-2007, 07:04 PM
  #2162  
AWorrest
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Default RE: Spektrum DX-7

Richard,

You are running five heavy duty, digital servos as well as two others. This may be pulling down your battery voltage. You didn't state how many cells in your Hydramax pack. From Tower's web site it appears this pack has four cells. Is this a low impedance NiMH pack? Does the pack voltage stay up when you move all your control surfaces simultaneously after having used it for some time?

I would guess you put too much of a load on your battery pack after having flown eight minutes. The voltage dropped and the receiver re-booted. As Danny Snyder replied to a similar question, the DX7 failsafe works for signal lost, not battery failure.

Allan
Old 06-07-2007, 02:07 AM
  #2163  
rino
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Default RE: Spektrum DX-7

Richard, sorry to hear about what happened. One simple test for peace of mind is to charge your pack to the level you believe your battery was at, install an inline amp/volt meter and with some load on the servos check your voltage in real time. A vmeter is worth the 35 bucks and will tell you a LOT about whats happening with your system. I did this and found that even with a 6v JR pack (high impedance) I was getting some pretty low voltage readings while just stalling 2 of my 5 digitals.

So, I went with nobs high-output 6v packs with 22 guage leads and a heavy duty 4 pole EMS switches with 22 guage wire. The interesting part is that this stuff cost less than the JR stock components I was running. Funny how that workedout. Now, I can easily service 8 amps to my rx and that's more than my 5 DS 821's can pull when completely stalled.
Old 06-07-2007, 03:58 AM
  #2164  
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Default RE: Spektrum DX-7


ORIGINAL: dick Hanson

If you really want to know if your battery setup is up to snuff -or if your servos are setup correctly---
purchase a simple little voltmeter by EXPERT.
available in 4.8 or 6 v.
weight is a few grams -plug it ANYWHERE into system which sees battery power with switch ON.
use a Y if needed to get there .
The little LCD display zips up to full when battery is full.
now move each servo full travel -watch the meter-

Basically-the meter sees actual voltage in entire circuit that the battery feeds.
So for example --if the battery reads high when nothing is moving - yet drops quickly when a certian servo moves - -you are seeing a "problem" with that servo or linkage.
Now - put a battery in the plane which is old or vey small or weak. and look at the meter - as you move the sticks - the meter will rapidly drop .
OR- stall a servo -again the meter drops .
The SIZE of a battery is important as is the IMPEDANCE--which is a fancy way of saying how easily the battry will release current.
Example a 2700ma pack with high impedance (these are common as fleas on a dog ) is a terrible choice for a model with 3D or active flying .
You would be better off with a 1400 ma pack with extremely low impedance .
tho the number of flights seemingly would be far less --in actual practice-the 2700ma pack would quickly be choking power (voltage)to low and very possibly below rx operating threshold.
This tiny readout will tell you more than a whole roomful of test equipment and $$chargers .
Why?
Simply because it shows what is happening AS it happens.

I use one of these a 6 v model-and a 2300 ma, A123 dual cell pack - NO reg -for my planes - until the cells hit under 3 volts - the current available will melt wires.
when ready to take off -I look into canopy at the meter - and move the sticks - IF for some reason the meter takes a dump- something is wrong - low cells stalled servo -whatever .
THAT kind of info simply is not available from stuff sitting on your shelf.
OK, I'll bite....
Who makes low impedance packs? Names please? Nimh is my prefered chemistry.

Dave
Old 06-07-2007, 05:22 AM
  #2165  
Maudib
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Default RE: Spektrum DX-7

No BS Batteries from Hangtime Hobbies

http://www.hangtimes.com/giantrxpacks.html
Old 06-07-2007, 08:56 AM
  #2166  
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Default RE: Spektrum DX-7


ORIGINAL: AWorrest

Richard,

You are running five heavy duty, digital servos as well as two others. This may be pulling down your battery voltage. You didn't state how many cells in your Hydramax pack. From Tower's web site it appears this pack has four cells. Is this a low impedance NiMH pack? Does the pack voltage stay up when you move all your control surfaces simultaneously after having used it for some time?

I would guess you put too much of a load on your battery pack after having flown eight minutes. The voltage dropped and the receiver re-booted. As Danny Snyder replied to a similar question, the DX7 failsafe works for signal lost, not battery failure.

Allan
The batery pack are 5 sub c Cells 6v not four, I also thaught that a low voltage was the problem, but The distributor of Horizon here in Mexico Contact me and we make some test, he connect a amp/volt Meter and we check that a low voltage cause the problem (like when Quique Somenzini lost his bipe Biplane for the same problem), but everything was ok the battery works ok, and in fact I was only preparing to landing, so I wasnt moving all the servos, Another question I have is Why the rudder start to move? If the battery was the problem simply any surface move.

Thanks Allan
Old 06-07-2007, 08:59 AM
  #2167  
best_panther
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Default RE: Spektrum DX-7


ORIGINAL: rino

Richard, sorry to hear about what happened. One simple test for peace of mind is to charge your pack to the level you believe your battery was at, install an inline amp/volt meter and with some load on the servos check your voltage in real time. A vmeter is worth the 35 bucks and will tell you a LOT about whats happening with your system. I did this and found that even with a 6v JR pack (high impedance) I was getting some pretty low voltage readings while just stalling 2 of my 5 digitals.

So, I went with nobs high-output 6v packs with 22 guage leads and a heavy duty 4 pole EMS switches with 22 guage wire. The interesting part is that this stuff cost less than the JR stock components I was running. Funny how that workedout. Now, I can easily service 8 amps to my rx and that's more than my 5 DS 821's can pull when completely stalled.
Hi Rino, I already make that test, and the highest load was from 2-2.50 amps only 2 or 3 times reach 3 amps, and that's because we put a very much load to the servos, so I guess that was not the problem.

Thanks.
Old 06-07-2007, 01:31 PM
  #2168  
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Default RE: Spektrum DX-7

Richard,

You seem to have eliminated low battery voltage as the source of your problem. If the plane is in good enough condition to give it a range check that would be the next item on my list before sending the equipment back to Horizon. Ideally I would do the test with the aircraft facing me and the engine running. Make sure the plane is securely tied down. Since the ground range, even when the bind button is held, is likely to be more than 100 paces, point the transmitter antenna directly at the plane. Get far enough away so the receiver goes into failsafe. If the engine doesn't go to idle or the rudder starts flapping, you have something to work with. If everything works properly, you got a mystery on your hands. Good luck.

Allan
Old 06-07-2007, 04:33 PM
  #2169  
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Default RE: Spektrum DX-7

Richard,

Thanks for sharing your results with us. Has Horizon shown any interest in testing your equipment? At this point it would be good to get all of your servos tested to rule that out. Were you running a decent switch? How about a bad extension or something like that?
Old 06-07-2007, 06:22 PM
  #2170  
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Default RE: Spektrum DX-7

All the intense conversation about batteries should be unnecessary with robustly designed systems.

Bill
Old 06-07-2007, 06:43 PM
  #2171  
Bob Pastorello
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Default RE: Spektrum DX-7


Decided it wasn't worth it.
Have fun.

ORIGINAL: BillS

All the intense conversation about batteries should be unnecessary with robustly designed systems.

Bill
Old 06-07-2007, 07:33 PM
  #2172  
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Default RE: Spektrum DX-7

edit
Old 06-08-2007, 01:23 AM
  #2173  
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Default RE: Spektrum DX-7

My Brain Is melting....I just spent an hour looking through this forum looking for the recommended battery set up for the radio. Can someone put their recomendations in one single post? I have understand that the 6v batteries with backup to be the best. Which companies batts are the best (I Know this Is Preferance). And which charging system is recommended? The electrical part of this hobby has always given me an ulcer. I reckon thats why i will not go to electric airplanes...LOL
Old 06-08-2007, 03:05 PM
  #2174  
Ed
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Default RE: Spektrum DX-7

The key to reliable AR-7000 operation, is just not letting your on board system voltage drop much below 4.8 volts, that's the working voltage for a 4 cell pack. It is said that re-boot happens down around 3.1 volts, thats 35% lower then 4.8 volts. Just don't let it get that low ! Depending on your systems load, number and type of servos used, select batteries with adequate capacity. And two packs with seperate switch harnesses are better than one, not only increasing capacity, but creating redundancy. Check out Red's site on how parallel packs are used. http://www.rcbatteryclinic.com/ Built in redundancy buys you aircraft insurance. You don't need a lot of voltage to operate an AR-7000 reliably, you just needs to take steps to prevent it from dropping too low.

> Jim
Old 06-08-2007, 06:03 PM
  #2175  
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Default RE: Spektrum DX-7


ORIGINAL: aerobob


Decided it wasn't worth it.
Have fun.

ORIGINAL: BillS

All the intense conversation about batteries should be unnecessary with robustly designed systems.

Bill
Bob, I run a design shop and have no tolerance for less than adequate designs. After casually describing the ‘reboot on low voltage’ to the VP of finance her only comment was: “Back to the drawing board.”

Bill

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