Modifiying a brand new Turnigy 9X

[Tranworld]

Having just received a cheap but very able RC system, the Turnigy 9x (and 4 extra EX), I set about modifying it even before I have used it in a model:

Done so far
1 - 1st mod was the addition of a tiny 8.2K resistor to allow the use of Lithium battery as explained by Bruce. However in my case I used AA size 14500 lithium, just two of those in the original holder plus some dummy battery to make the circuit, I plan to eventually use 2 AA battery holder instead.
2 - Solder an additional 2 pin power socket (RED) as used in RX battery circuit etc. this will make it easier to add the 2 AA holder as above, this type of connector is sold in RC shop for making up small battery pack, easir to find than the original 3 pins.
3 - Remove the original charging socket as these can't be used for the Lithium, instead I created a 6 pin round port for the connection with an external AVR programmer, this is a passive connection only. The round PC keyboard/mouse style socket fits really well into the charging hole.
4 - Make the antenna retractable ! Yes even with the short 2.4GHz antenna I don't like the way it stick out on top which make it more fragile when transporting. So I added a length of tube inside the case and push the original antenna back, when in use just tip the TX down and it will drop out a bit, then pull it to make it come out all the way, the springing plastic fits just right inside the antenna receptable in the TX to keep it there by friction. You have to remove the original mounting hardware of the antenna, this is easy as they only clip and screw in, no cutting.
5 - Shorten the stick, to fit my thumb better (cut with a Dremmel)
6 - Make the 4th stick channel also center springed (by shaping a piece of plastic similar to those used in the other 3 fucntions)
7 - Fitted the backlighting panl bought at the same time from HobbyKing (this is LED and does not need any noisy driver, simply run off 5V)

To do
8 - Solder on the connecting wires for the programming port
9 - Reflash it with custom firmware as and when I bought the programmer, will then remove the resistor in 1 as the alarm voltage can be adjusted in the custom firmware.
10 - Replace all the internal voltage regulator with low drop out type, however I will do this only after making sure that the TX has worked well for a while, just so that I know any problems are not due to this.

I think the above conclude my requirement for a custom TX and thankfully the Turnigy lend itself into it very very well, they way its made make it easy for conversion (heck even the main board has pads to solder on the programming interface) and the fact that it is cheap so I mod it it without too much fear.

[Tranworld]

Oh and another improvement to be done, sleeving most of the screw holes with a brass tube, I found that these can crack open after repeated opening and closing and putting a good sleeve over them now will prevent it from happening in the future (in fact in the case of an laready cracked one, you could repair it with similar way and perhaps a drop of Cyano

[caseih]

wrong thread!

[Tranworld]

I don't see why you need an antenna mount? This is the version with a short antenna and it just slide back inside the tube when in "retracted" mode, I added a bit of foam at the end of the tube to provide a stop and make it so that the tip just stick out enough for your finger to pick it and pull it out, bute being foam you can also push it further and it will spring back, I will try to find a plastic cap that will fit over the top and "close" it off when not in use. A side effect of this may be is that you may be able to range test easier as the antenna will be attenuated by the surrounding boards.

I don't want to convert it to 72MHz, I am keeping the 2.4GHz module and all, this is only so that I can retract the 2.4GHz antenna

[caseih]

I think I replied to the wrong post! Sorry.

[Tranworld]

I think another idea is to build a set of battery inside the TX, leaving the battery compartment free for other spare, or for plugging in another battery should the internal one be depleted mid-session.
I will use 18650 cells that Bruce uses in his $8 modification, but these are harvested from unused laptop battery pack (most of these contains 18650 type cells), the one I have are joined in parallel giving 4800mA per cell (2 cells welded in parallel inside the pack). using two packs will give me a whopping 7.2v 4800mAh internal battery.
The connectors will be located within the battery compartment so that I can still unplug the internal one and plug in any emergency pack !

[aesmith]

Where do you find enough space to fit 4 x 18650 cells inside the transmitter? I'm still not set exactly where to mount everything. Currently the Frsky DHT is mounted internally with the switch/LED panel mounted up front where the Turnigy badge used to be. I have a pair of 18650s in the battery compartment, together with a loose XT60 connector so they can be charged without removing the pack, and the USB port is in there as well. I don't have RS232 brought out yet for programming the DHT. As of now the module case is just an empty box, so potentially I could mount everything in there.

[Tranworld]

I am not sure where to mount the twin 18650 but may be on the two side where the bulge for the handle is? Have not tried it yet though, alternatively just single 18650 x2 on the PCB beside the antenna?

[Shotglass]

i can recommend these
http://www.hobbyking.com/hobbyking/stor ... duct=14076
theyre cheap theyre life (no worries about the battery ever going up in flames) they fit perfectly and they require 0 modifications other than soldering a different connector to them