Spektrum DX7 and DX3S EL Backlight Mod

[uopercival]

Been hovering around the forums lately and decided to make my first post. I picked up a Losi MRC last weekend and have really enjoyed it. I wasn't sure i'd be into the crawlers but now I understand the attraction.
I spent the last 2 nights doing a mod on my transmitters, it was hairy at times but I got her done.

The dx7 was very tight inside, I had to gut the inverter up into 2 pieces to make it fit. The dx3s was easier, there's lots of room inside. I also added a switch to the top of the DX3S to allow me to turn it off when outside. Oh and added a couple of blue LEDs to match.

Let me know if anyone wants to attempt this and I will try to give better instructions.

[4x4Crawler4LIFE]

I am going to buy a DX7 SE in the next month and I crawl at night a lot (due to all my LED lights lol)
and this would be really cool MOD.
please post some pics and share.

did you take any pics as you where doing it?

also was it just adding Blue LED's?

please show us!!! hahahah

it is tooooo Awesome not to show !

great 1st post!!!!!!!!!!

[RobCam]

great job! show us your mod its what ive been needing for some midnight crawling!

[666]

More info!!

[cartronicshn]

Nice, any pics on how to get it done?

[Flyin Hawaiian]

More Info please

[uopercival]

Ok, here's some more info, it's not intended as a step by step guide, but those with some electronics/technical background will have no problems. Let's get the disclaimer done, i'm not responsible for you damaging your transmitter, you do this project at your own risk etc etc.
The mod is fairly challenging but hey that's why we're all in this forum, we like to tinker and mod our stuff.
Please forgive me if it gets too technical, I wanna provide as much info and hints as needed.

First thing you'll need is an EL sheet kit (electroluminescent). You can find these on ebay and they are pretty cheap. The kit will consist of a sheet of EL, some pins to stab into it and an inverter that will convert your DC voltage to the voltage the panel needs (something like 100V AC).
The inverter that came with my kit was designed for 12V operation and as with all EL lighting, the inverter did have a slight high pitched whine while operating. I lowered the amount of whine and brightness by putting in a 5V regulator in the DX7 and ran it at full voltage (6V) on the DX3s. The panel operates perfectly at 5V and is about the right brightness. In hindsight, I would have tried to find a smaller inverter, the one in the picture is fairly big and made the mod a little harder.



Inside either transmitter, you'll find that the LCD panel is attached to the mainboard via ribbon cable. Bottom and centre of this pic. One of the many noob mistakes is just yanking the cable out, don't do it. The brown part of the connector slides away from the white part then the ribbon comes out with no effort. Same deal going back in, have the brown part out, put ribbon in squarely and push the brown part back in towards the white part.


With the LCD panel removed, the first thing to do is remove the reflective foil that is on the back side. It's like peeling off a label and you'll be left with all the adhesive on the LCD. At this point I tried sticking the EL panel on to the LCD but image was way too dark and there were 2 tiny air bubbles that were unacceptable. The adhesive is very stubborn. Here's the hint. Run the entire LCD panel under some warm water, dry it and start rubbing the adhesive towards the middle of the LCD. Re-warm the adhesive as necessary. This was the easiest way to do it. I tried goof off, goo-gone etc but the adhesive seems to be temp. activated. A heat gun would work too just don't overheat glass.


Next, cut a piece of the EL to size. Hint, don't use an exacto like i did, as you press down with the knife, the layers (4) of the EL separate due to the pressure. Scissors did a way better job. Remember that you'll need some of the contacts available near the bottom of the panel. At this point follow the instructions from the kit and install the metal pins onto the EL panel. As soon as you do that, you can hook it up to the inverter and give it a test. If it lights up evenly, then you've done a good job. If it lights up all blotchy, then cut a new one cuz the sheets in the EL may have separated.


Once the EL panel is cut to size, place it behind the LCD panel and reinstall that portion of it. Major Hint: For both of my receivers, I had to leave out the original installation hardward for the LCD panel. The EL along with the contacts simply made them slightly too thick to reinstall with the original plastic mounts. I even tried grinding away some plastic but the best solution ended up being some thin foam behind the EL to keep it in place and reinstallation of the mainboard up against the foam. IF you see any discoloration on the LCD panel after you reinstall it, re-do it. The discoloration shows that there is abnormal pressure on the glass and IT WILL CRACK.

The last step is to shoe horn the inverter into the transmitter. In the DX3s there was a ton of room. As you can see, I removed the casing from the inverter to make it even smaller. DO put some lexan or plastic around the inverter once it's installed. This thing puts out 100V, nothing to sneeze at, and if you're not scared, keep in mind that the Spektrum electronics runs at 3.3V - imagine if you put 100V in, yeah, you might get wicked range but only for half a second.
As mentioned at the beginning, try to find a small inverter, while this particular one fit fine in the DX3s, i had to remove and relocate the transformer and flatten all the components to make it fit into the DX7.


And there you have it. The rest is easy, just tie in the supply, connect the output to the EL panel. Install a switch if you want and away you go.

Good luck and happy hacking.

[cartronicshn]

Still interested in the how to.

[Nova's Ark]

Very interested in this mod, please post a how to or link to where you saw it done;). That blue on the DX7 looks great.

[cartronicshn]

Check this out
http://www.youtube.com/watch?v=G-7U85D6LMA

[Nova's Ark]

Originally Posted by cartronicshn

Check this out
http://www.youtube.com/watch?v=G-7U85D6LMA

That's a great find, but how do they do it? I hope it's fairly easy, I sure don't want to screw up a $200 radio.

[uopercival]

I posted a mini-guide but for some reason it didn't go up yet. I wonder if the moderator has to approve it since i'm newbie status.
I'd hate to have to repost it. It was quite long.

[Racer4Life]

Yes...more info. I did this to a Duratrax Charger once. Pain in the butt.

Where did you get the screen at? I need one for a DX3R.

[Racer4Life]

Did the text change when you changed the screen? I have never seen the text on a DX3S, but it is different from my DX3R.

[uopercival]

bah, i just redid a guide again and tried to post it. says moderator has to approve it before it shows up.

anyway, when the moderator gets around to it, there should be 2 guides that will show up here.

[Racer4Life]

Originally Posted by uopercival

bah, i just redid a guide again and tried to post it. says moderator has to approve it before it shows up.

anyway, when the moderator gets around to it, there should be 2 guides that will show up here.

Just post a thread here!

[uopercival]

That's what I did, I hit the post reply button, type in all the stuff and include a bunch of pictures and hit submit reply.
Maybe there's too many photos? (5) or maybe my reply is too long?

BTW- that's the standard screen.
Here's what the 3 default screens look like. (sorry about the focus, was too lazy to set up the tripod)

[uopercival]

I'm gonna try posting in 3 parts to see if it get's posted.

First off, the disclaimer: I am not responsible for you damaging your radio by attempting to perform this mod. Yada Yada. This mod isn't for the faint of heart and uses electrolumiscent lighting which operates at around 100V AC. The mod is challenging (yet rewarding) and can be done in about 2 hours.

This is not meant to be a step by step guide, I don't really want to list each and every screw that needs to be removed etc. However, I will highlight areas that I had the most difficulty with and how to overcome them. I've seen the work that goes on here in these forums, this mod will be fairly basic for most of you.

Here we go....


First off, you will need an EL Sheet Kit, I found mine on ebay for about $13. The kit consists of a sheet of EL which you can cut to size, some metal pins to make contacts and an inverter that will convert your DC voltage to 100V AC. A note here: The inverter that came with my kit was fairly large, it was epoxied inside a roughly 2x1.5.1.5 plastic case. If possible, find something smaller. I ended up cutting the case up to get the guts out so that I could fit it into the radios. The EL sheets can come in different colors , i chose blue but i'm sure white would look cool or maybe Spektrum orange!

Open up your radio. On the DX7, it's pretty simple, a few screws on the back and you're in. The DX3s is trickier, you will need to remove 3 stickers: the one around the LCD screen, the DX3s sticker that's just above it and the side sticker near the charging jack. Just remove them at a carefully to prevent creasing and they will go back on fine later. There's also a screw under the front rubber grip so remove that as well.


The next step is to remove the LCD panel, there are 4 screws to remove on both the DX7 and DX3s. I wanted to show here how the LCD panel is attached to the main board. You can see that at the bottom of the photo there is a ribbon cable, most noobs will try to just yank it out but it is actually a zero insertion force connector, so the brown part of the connector will push down and away from the white part after that the ribbon cable then simply slides out. Same in reassembling, make sure the brown piece is slid out all the way, push cable in all the way and push the brown clip towards the white part to lock it in. The above pic shows the DX7, the DX3s has a similar connector.

[uopercival]

Part 2


Once you have the LCD panel out you will need to remove the reflective film that is on the back. Peel it away being careful not to put too much stress on the LCD, you will notice the panel discolor a little as you're pulling, but don't worry, once it's powered up, it will reset. The adhesive from the sticker will stay on the panel, don't worry about getting dust or fingers on the adhesive. I tried using the adhesive with the EL sheet but the results were poor. I ended up removing the adhesive using goof off and goo-gone but nothing worked as well as running the LCD panel under hot water to heat up the adhesive and then rubbing it off from the edges towards the center. Re-warm the adhesive as needed. Once the really gooey stuff is gone, use goo-gone to remove any residue. You should end up with a perfectly clean piece of LCD glass. (A heat gun might work as well, just don't overheat the LCD panel.)


Now cut a piece of the EL down to size, DON'T use a knife like I did, the pressure from the knife pressing down on the EL panel causes the layers to separate. Use a sharp pair of scissors and trim the EL as needed until it fits perfectly behind the LCD panel. Read the instructions that come with your EL panel regarding how the contacts work. You basically push pins near the bottom of the EL panel to make contact with the 2 different layers. Once you have the pins in, you can test it out with the inverter and make sure it lights up evenly. Insulate any bare parts of the pins with a little tape.

Now, putting the LCD and EL together.. place the EL panel behind the LCD and tape them together along the edges, you can have some tape near the very edge of the LCD panel as it won't show up once it's back in the radio since there is a bezel around the LCD. On the DX7, I didn't use the plastic pieces that hold the LCD against the face of the radio. I simply aligned the screen up, placed a piece of foam behind the LCD and then rescrewed the main board against it. On the DX3s, I used only the front piece of plastic and not the back. Again, I used some foam and put the mainboard back behind the LCD. You won't be able to screw the mainboard back on, but it has no where to go. I initially tried to use all the original mounting hardware but the EL along with the contacts makes the whole thing just a tad too thick. DON'T force them together, if you see any discoloration on the LCD screen you will know that there is abnormal pressure on the screen. Re-mount it. If you leave it, the LCD screen will eventually crack. Once all LCD is all mounted, you can test it again with the inverter and get a good idea of what it's gonna look like. You'll be remounting if you see fingerprints or dust.

[uopercival]

Part 3


The last step is to mount the inverter. As I mentioned earlier, my inverter was kinda large, I ended up removing the plastic casing and mounting it without the case. In the DX7 I actually had to remove and relocate the transformer from the inverter and then flatten the other components to make it fit. The DX3s had lots of room, I added a small switch so that I could turn off the backlighting when I'm outside. A note about the inverters... first off they have a very faint high pitched whine to them, you can limit the whine by lowering the input voltage. My 12V inverter works perfect inside the DX3S operating at 6V, the EL panel is at a perfect brightness too. On the DX7 the 10V made the inverter a bit too loud for my tastes so I threw in a 5V regulator. Also since we're only using a small portion of the EL sheet, it's really not necesary to run the inverter at the full 12V. Keep in mind that you also have contrast controls on both the DX3s and DX7.

Final thing before putting it back together, isolate the inverters by putting some lexan or even the clear plastic from a blister pack between the inverter and the radio electronics. The inverters put out 100V, your radio actually runs at 3.3V - yeah you might get wicked range but only for a moment .