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Old Mar 10, 2007, 11:47 PM
Heli Headcase
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Cliffside Park, NJ
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Switching DX7 to Mode 3

I've read it is possible to switch a DX7 to a Mode 3 by starting off with the Mode 1 version. You have to swap the 4 sets of 3 wires that go to the Aileron and rudder gimbal pots and trims. This is the best way to do it according to Paul Beard. I opened the back of my Mode 1 DX7 and I only see what I think are the 2 set of wires for the trim controls. I think there is suppose to be another set for the gimbal pots but im not quite sure where they would be. I attached a picture of the wires im talking about. Im guessing these are only for the trims. Where would the gimbal pot wires be? Do I have to take apart anything else to get to them? Im hoping someone who has knowledge in this particular area could help me out. Thanks for any help on this.
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Old Mar 11, 2007, 06:25 PM
Heli Headcase
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no one knows how to get to the rudder / aileron gimbal pot cables? Ok forget about the DX7 where would they be normally? Do you have to remove the gimbal assy to get to them?
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Old Mar 11, 2007, 07:36 PM
Guz
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They should go to the main-board, or a sub-board.

It looks like you will have to do some dissecting to find them. Just take your time, and mark each little plug you take off with where it goes on the boards.

If you notice, each plug receptacle on the boards are silk labeled. Take some masking tape, and write down what each receptacle is labeled as, then remove the plug and put the tape on the plug.

It's time consuming, but it's the best way to go.

Oh, since you have a camera, take pictures as you go. Helps for those moments of "Oh man, which way did this plug go!?!?!?"

Oh, I would pull up the Rf board first, it looks like those leads go under it.

I really wish the *%$#^#! programmers of these Asian Radios would just do software selection of all the stick modes (1, 2, 3, 4). That would save us all these headaches.
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Old Mar 11, 2007, 08:04 PM
Heli Headcase
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One of the guys on Runryder who did the switch told me he only switched the bottom two wire sets I have circled. Sounds weird to me cuz it only looks like you would swap the trim assignments. He said his is working fine after 100 flights. The only drawback is that the trim adjustments are reversed. Oh well I'll start with thosse and see what happens.
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Old Mar 11, 2007, 08:24 PM
Guz
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If you want your trim buttons to go with the gimbal, you have to dig further and swap those connections also. Or you won't have the trim buttons in the right positions.

I wouldn't go un-soldering anything. I would dig to the connectors on the boards.
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Old Mar 12, 2007, 05:14 PM
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Guz,

The software programmers do allow software programming for Mode change. It is the US Distributors that ask for certain sets to non user mode changeable.

The DX7 software has been modified on behalf of Horizon to remove this function.
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Old Mar 12, 2007, 05:48 PM
Mexia Izonfia
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I think the wires you have circled are opposite ends of the same wires. It looks like there is a small PCB on the back of the trim switch, and that the Red/Blue/Black and Yellow/Blue/Black wires go from the trim switchs to the gimble pots. It looks like there are four or five wires from the trim switch PCB that run to the main PCB (see red oval). I'll bet these are the wires that need to be swapped.

- Joel -
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Old Mar 12, 2007, 06:39 PM
Guz
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Quote:
Originally Posted by mac_man
Guz,

The software programmers do allow software programming for Mode change. It is the US Distributors that ask for certain sets to non user mode changeable.

The DX7 software has been modified on behalf of Horizon to remove this function.
That is just asinine.

What's the deal? Don't they trust us to be able to change stick modes? So they make us do surgery on our transmitters. Stupid, just plain stupid.
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Old Mar 12, 2007, 07:13 PM
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Ermmm yep !
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Old Mar 12, 2007, 08:26 PM
Guz
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So, I guess this discussion begs the next question...

How do we get these distributors / manufacturers to put in the option to have at least stick modes 1 through 4?!?!?!?
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Old Mar 12, 2007, 10:53 PM
Heli Headcase
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Ok guys I unsoldered then swapped the two sets of wires at the bottom. To me it seemed easier to do it this way then do a cable swap. The cables would of needed to be cut then extended b/c they were to short to extend to the other side. Anyway thats all I did tonight. Pretty nerve racking experience for me considering Im not the most graceful soldering tech... I didnt try to bind anything yet but I did go into the servo travel/centering screen and sure enough the right stick when moved left & right is moving the rudder channel and left stick aileron. My trim settings are going to be on the opposite side but I think I can live with this. I got this far I dont want to push my luck.

My centers are a little off so I will go into the service menu and recenter everything. Thanks for the comments. So much for my warranty
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Old Sep 07, 2007, 02:38 PM
smoking a buddy box
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Hi,

Some info for mode change of the DX7 here :
http://www.mugi.co.uk/tutorials_dx7_modechange.php

Olivier
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Old Sep 07, 2007, 02:55 PM
Crash=change of flying medium
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I've got a similar problem--bought DX7 from a guy here at the forums, but he hasn't mentioned (intentionally?) that the transmitter is Mode 1...

I've figured out how to swap the wires, but, at the end, found that the throttle potentiometer has lower resistance range than the other pots. The ADC accounts for that, interpreting smaller changes of the throttle pot as bigger changes of the throttle channel level. As a result, swapping the wires without moving the pots around makes the elevator travel about +-120%, while the throttle travel is reduced to roughly +-80%!

Now, I'll have to swap the potentiometers too...


Boris
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Old Sep 07, 2007, 06:30 PM
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bluesky,

the pots should all have the same value... 5K. Does the throttle stick (original) have a reduced travel range ? If its not equal to the other stick, you may be fitted with limiters on the throttle stick. These are 2 small plastic wedges fitted in the stick base.
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Old Sep 07, 2007, 06:56 PM
Crash=change of flying medium
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Quote:
Originally Posted by mac_man
the pots should all have the same value 5K.
The logic tells that they should, but nobody prevents JR/Spektrum from defying the logic!

Quote:
Originally Posted by mac_man
Does the throttle stick (original) have a reduced travel range ? If its not equal to the other stick, you may be fitted with limiters on the throttle stick. These are 2 small plastic wedges fitted in the stick base.
I will carefully look at this.

What makes me believe that the two pots are different is that, after I swapped wires between the throttle and the elevator pots, I see the following channel travels, measured using MileHighWings 10-bit precision interface (all channel's end points are set to 100%):
Throttle: +-80%
Aileron: +-100%
Elevator: +-120%
Rudder: +-100%
If only the throttle stick were mechanically limited, then this would only affect one channels.

I will try to measure the resistance of both pots, if I can get access to them (I will, as I/m going to mechanically swap them).

Boris
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