DX-7.... explain this!

[stommerd27]

Rede2fly has a good point. I had an older JR computer radio I can't remember for sure the # XP831? Any way I stored a couple of planes into it flew them all day. Came back the next day and poof the memories were gone. It ended up being the little lithium watch battery inside the TX.

[50%plane]

	Quote: Originally Posted by RappyMan
	Horizon Hobby call leaves me depressed. Rusty listened to the description & requested the radio be sent in. The radio has a 3 year warranty so they will stand behind the radio but most likely nothing else. Turn around time is about 5 days.. a few days to ship there... a few days back... so the warbird event is before the radio would be back. The above is standard policy.... but there was nothing that cheered me up. No offer to swap the model memory to a different radio & get us going for the warbird night. Did not want to see video to see the issue and hurry up the turn around. I was hoping for a bit more "DA" style service here. Not even a "hey, that's terrible... sorry man!" about what happened.

	Quote: Originally Posted by RappyMan
	So it's pretty much unanimous on the pre-flight check then? Ha ha! You could be president - ignore the obvious and focus on something else. There's no where I haven't agreed with: a second pre-flight before the second flight would have saved the plane. What's the reason the plane is wrecked? The DX-7 took a dump! A pre-flight would have caught this.... but the reason the plane crashed is the DX-7 forgot that we just reversed the ailerons 15 minutes ago. (A pre-flight would have caught this!!! (I'm repeating it over and over so you don't have to!)) It's also interesting that 3 others have had the same problem - out of the 500 or so that have looked at the thread. One seemed to be fixed by charging the battery, one just had to re-enter the info & not sure on the other. Spektrum (JR) is a pretty well known name - it's not a start up with unknown quality. Does anyone know what would be required to fix the condition? What's the probablity it might happen again? Is shelving / stomping on it and getting something else the way to go? I'm hoping for some confidence in the radio again & don't want to chance something else. Thankfully the 260 just hit into a field & not something or someone. If anyone has helpful info (other than preflight (got it!)) please let know. Thanks Terry

Ok Terry, so now that we've estabolished that you did not preflight, and the plane crashed, and Horizon is doing everything that you agreed to when you bought the radio. What's the issue, and why so you feel depressed after talking to Horizon? Sounds like a novel. the end. Right?

Yes, your DX7 had an issue. Nothing's perfect, however I agree, it should have been expected to perform without a hitch. However, there's always a chance that something will fail. Horizon offered to fix it, where's the problem?

[JimC-MD]

OK, this will be as constructive as I can make it.

Have you looked for any anomalies with the other 13 models that are stored on the radio? Have you tried going in and reversing the aileron channel on another model selection to see if it retains that one?

Here is what I am thinking. There could be a sequence of "keystroke" or commands that when executed in a specific order cause an unexpected error. The other issue could be something like a corrupted spot in the memory. Who knows. If every other model holds changes on the radio then there is a quirk. I think the video would be helpful to see if the sequence of commands are the issue.

Stuff happens in this hobby. I am currently dealing with about a half dozen little issues with various birds in my fleet. All but two of them are directly caused by me, either from missing a detail or not catching an issue fast enough. Oh, and I walked the tail feathers of a Sukhoi into a wall by accident. The others are due to how a product was packaged causing some shipping damage (will not keep me out of the air unless I chose not to spend an extra $30 I had not planned on) and the purchase of some stock that was not of the newest variety (flashing quick connect firmware). It sucks, but it happens.

I am really sorry you lost that plane. I really am curious about my question on the other memory slots.

BTW, and I could be wrong on this. I thought the use of volatile memory requiring a battery for backup was a thing of the past. I thought we were writing to another type of memory now, more like a thumb drive. If this was a "memory battery" type issue, then at power on there would be no models stored, it would all be back to factory default.

One last thing.

PREFLIGHT!!!!

Sorry, could not resist. Hope you are in the air soon.

[Zeeb]

	Quote: Originally Posted by JimC-MD
	BTW, and I could be wrong on this. I thought the use of volatile memory requiring a battery for backup was a thing of the past. I thought we were writing to another type of memory now, more like a thumb drive. If this was a "memory battery" type issue, then at power on there would be no models stored, it would all be back to factory default.

That is correct. I'm not positive if it's still known as an EEPROM (Electronically Eraseable, Programmable, Read only, Memory) but it works the same way. Data is written to the chip when the power is turned off. This requires not cutting the power to the tx completely until that volitile memory is written to the chip.

This was part of the problem with the FASST tx's being shut off and turned on again too quickly. It corrupted the firmware giving them the 0 GUID issue. If you note on your JR/Spektrum stuff, it takes a few seconds for the tx to completely shut down after the switch is turned off. I don't remember exactly what my DX7 did, but the X9303 gives you a horizontal line across the display right after it is shut off while it writes data.

[RappyMan]

Hi Jim
Thanks for the constructive info there. I've tried changing other things like expo & it dissappears after the TX is turned off. This also happens on other models. I've went to models 12 and 14 and changed things & that change dissappeared as soon as the radio was turned off and back on. The TX does remember what model it was on... just not any changes.

Preflight was painfully obvious as we were testing things out at the crash site. It hasn't got much more obvious than then. If we were really doing it right, the pre-flight would include a range check, pulling on control surfaces to check hinges, pushing on the control surfaces to check for slop & servo torque, prop bolt and motor mount bolt tightness... ect (before every flight.) I went to a fun fly that was a blast last weekend & never saw a single person do a range check. I'm just an ordinary guy & we missed the ailerons being backwards on the 2nd flight. The radio did something unexpected and it wasn't caught. Hopefully the video of this wierd behavior and the picture will help someone else from having the same story.

Thanks
Terry

[bodywerks]

	Quote: Originally Posted by Rickster
	OK.. For everyone that is waving the "Pre-Flight " Flag at him... Say for the sake of argument you have just bult a cherry perfect A-4 Skyhawk or maybe a scaled out P-40 (Some may see where this is heading).. You fuel it up, all your buddies and even the camera crew for Model Aviation and RC modeler are there to see you maiden this beuty and capture it on still and video for all the modeling world to see... You turn on your trusty DX with total confidence and with all the congregation's hoorays you turn on the airborn and then..... WHAMMMMMM The gears retract out from under it and it slams donw on the concrete battle scarring up the gear doors and underside of the aircraft.... NOW WHAT????? All the preflighting in the world would not have revealed this.... Rick

No, but reading the radio's instructions could have. It has been made VERY obvious,as far as I am concerned, that once you program your radio, you need to rebind it, and you need to do so with the gear switch in the 'extend' position. When first powering up the receiver, it reverts all servos to their Failsafe positions until it links up with the transmitter. Otherwise, you get what you got in your little scenario. I have seen it happen in person, and I can't help but bust out laughing:

The AR7000 features the SmartSafe™ fail-safe system.
SmartSafe:
• Prevents unintentional electric motor response on start-up.
• Eliminates the possibility of overdriving servos on start-up.
• Establishes low-throttle failsafe if the RF signal is lost.
• Maintains last-commanded control surface position in the event of RF link interruption.
Note: Fail-safe positions are stored via the stick and switch positions on the transmitter during binding.

copied and pasted that from the DX-7 manual as well...

[rking]

you mention proper preflights having to include checking the control surfaces, linkages, tightness of bolts, etc. i totally agree with that and am also guilty of having missed on checking some of these things in the past. i have NEVER missed though on checking correct control surface movement. i personally do a complete inspection of the airframe and its components at home usually the night before going to the field but again, better to check everything before every flight.

we do not live in a perfect world and no matter how much our equipment has been reliable or worked perfectly in the past, we would always have to assume that something could go wrong. it is always a risk once we start our planes and go up in the air. as aero-modellers, it is always our responsibility to minimize the risks involved when we operate our aircraft and that is why pre-flights are a must.

[Rickster]

	Quote:
	When first powering up the receiver, it reverts all servos to their Failsafe positions until it links up with the transmitter.

IF the retract channel is the channel in question that is not staying set, in my given scenario, would the gear not stay extended during the failsafe term and then once it links up the transmitter would then send the reversed gear channel command to the reciever?

Rick

[bodywerks]

When you first bind a receiver, it remembers however you had your transmitter set up at the time. Let's say that when it was first bound, you had the retract switch in the position you would want it for "gear down". But in the process of setting up the retracts, you had to reverse the gear channel in the 'servo reverse' function in order for the gear to go down when the gear swtich was in the 'down' position. That means that, the actual failsafe position that the transmitter assumed when it was first bound was the "gear up" position, not gear down, even though that is where you had the switch positioned. That is one scenario where the gear would retract on power-up if you did not re-bind the system after programming the radio.
Another scenario would be if you had air retracts and you had to adjust the ATV's to actuate the valve a proper amount. Let's say you needed 125% atv to make it work. If you do not re-bind after that, then the receiver assumes the 100% ATV value, which may reduce the throw enough to cause the valve to retract the gear.
To answer your question, if you did not re-bind the system after programming the gear channel, then it will assume whatever position signal (the actual switch/stick position is not what the binding process remembers for the failsafe - it's the signal that that particular configuration sends)it was receiving from the transmitter at the time of the first binding process. If it happened to be that the gear channel was reversed (not going the direction you wanted it - so the "gear down" switch position was actually sending a "gear up" signal) during the first binding process, then the receiver remembers the signal it received during the first bind, until it links up with the transmitter. So it would momentarily retract the gear, then try to extend them once it linked up with the transmitter.
Bottom line, the only way your scenario happens is if the system was not re-bound after programming, with all servos/channels going in the correct direction in relation to stick/switch movement, and with all switches in the proper configuration (such as the gear switch in the "gear down" position).

[bodywerks]

In re-watching the original poster's video, I noticed that he didn't first exit the setup menu after reversing the servo??? I don't have my DX-7 anymore, but I remember having a similar deal with a 7202 (which is what the DX-7 is), where certain settings changed would not be remembered if you didn't first exit the setup menu prior to turning off the transmitter. Can anyone with a DX-7 verify/discount this scenario?

[RappyMan]

Check the vid again - I go into the menu, change aileron reversing, get out of menu, go back in to show the aileron setting is still changed & back out of the menu again. Then the radio is shut off for a few seconds and back on again. The reversing menu is shown - and the position of the aileron has went back to the original spot (not where I changed it to.)

If you can spot anything that should be done differently, please let me know.

Thanks,
Terry

[Jurgen Heilig]

	Quote: Originally Posted by RappyMan
	... I've tried changing other things like expo & it dissappears after the TX is turned off. This also happens on other models. I've went to models 12 and 14 and changed things & that change dissappeared as soon as the radio was turned off and back on. The TX does remember what model it was on... just not any changes. ...

Hi Terry,

On your video, obviously your tx at least remembered the reversed channel for throttle. Again: Is there any difference when you leave the programming mode first and then shutting the tx off and shutting the tx off while in programming mode?

Jürgen