Thread: How To: Spektrum DX7 LCD Back Light Mod.

At long last I have done my back light modification to my DX7 and have written a “How To” for anyone wishing to do their own. A list of components and their suppliers will be at the bottom of this page. Some of the Photo’s are not in focus, but it was too late once I loaded them to my computer as the Tx was back together. I also took this opportunity to do the ball race mod as well.
Now the boring bit:-
This is how I did mine, and it is entirely your responsibility and at your own risk if you copy this process. It will make your warrantee void on your transmitter.

I carried this out following lots of research and contact with people in the USA and Canada for advice and components that they had used successfully.

1. Remove battery and back of Tx.

2. Remove internal screws on the bottom PCB marked on the photo below.



3. Slide grey tab down with finger nails to release the ribbon cable (do not pull cable before releasing clamp).

4. Lift PCB, swivelling the board from the bottom upwards. This will expose the LCD display that will just lift out.



5. Make a note of position of the plastic LCD retainers and then remove from LCD by sliding off sideways. There are 2 tabs that need to be trimmed flat, as shown in the picture shown below.




6. Using a thin blade (exacto/scalpel) carefully lift the corner of the silver foil backing on the LCD. NB, you must leave the “green” polarising layer in place. GENTLY peel off the foil and do not apply too much pressure on the glass screen or it WILL crack. Once foil is removed, there is a layer of adhesive on the glass that can be “rolled” off using your thumbs/fingers.




7. Cut your EL panel to size using sharp scissors only. Do not use a knife, the pressure can separate the layers of the panel.



8. Now solder on a length of twisted wire ( reduced RF noise) and use heat shrink to cover any bare wire. Use some black PVC tape to hold the panel to the screen, but not up to the ends where the plastic retainers fit. You need to keep the extra thickness of the panel to a minimum.



9. Re-fit the retainers to the screen. Do not use any pressure (you will crack the glass), then use the small location pins on the retainers to line up with the holes in the PCB. Now install the 2 inner screws but not tight. The screen is not going anywhere. Put the PBC back into the Tx and install the outer 2 screws. Gently insert ribbon cable back into its socket and press grey clip back into place to secure the cable.



10. Now for wiring it all up! I wanted to turn mine on and off, as and when I needed it, so I installed a toggle switch for this. Follow the diagrams for the wiring and make sure you use heat shrink on all the joints and use twisted cables.



11. I also opted to install the DE-SW033 at the same time, as this uses a lot less battery power. I use the V.in and ground from this to power my back light. See the photo below.



12. Make sure no wires are fouling the locating pins for the back panel. The inverter will need to be loose in the bottom left corner and it will just fit with the wires adjacent to the charge socket. The 5v voltage regulator will fit in the bottom right hand corner adjacent to the trainer socket. Please see photo below.







Now you should have this!



List of Parts I used

Red & Black Wire: Equipment Wire (7/0.2) : Equipment Wire : Maplin

Ultra Miniature Toggle Switch: Ultra Miniature Toggle Switches : Toggle Switches : Maplin

EL Panel/Inverter: Conrad Electronic International - Europe's leading mail-order business for electronics and technology.

Voltage Regulator DE SW033: 3.3V switching voltage regulator - 7803 replacements

Voltage Regulator DE SW050: Switching voltage regulators - 7805 replacements

Servo ext lead. (I used both ends to make a plug and socket to disconnect the switch for easy removal of the Tx backpanel.

Heatshrink tubing. I used 3mm diameter.

Tools I used

Small Phillips Screwdriver
Exacto Knife and sharp scissors
Soldering Iron and Solder
Wire cutters and Plyers
Electrical PVC tape
Drill and 5mm bit (if fitting switch)

Common Sense!

Good Luck

PS, If you have any questions I can try and help, post them on here or PM me.

HI that looks the nuts,,,I'm gonna have to do this................ How much did this all cost...??

gonna need some darker shades for that!! Do they make one an el panel that cant be seen from space?

Originally Posted by jamiem

gonna need some darker shades for that!! Do they make one an el panel that cant be seen from space?

PMSL Its not that bright in real life!! It really stood out in the house on camera.

Cheers Rob,

That looks really good, just used the link for the EL sheet and it's not directing me to the actual product! Can you please place a direct link for all those interested in this mod?

Originally Posted by mark351974

How much did this all cost...??

I will add it up tomorrow and let you know.

Not as much as you might think!

Well done Rob, nice mod and an excellent write up.
Being a total noob to electronic messing-around-ery (that's a word!!) I would need clarification on point 8 above as to what should be soldered to what.
Maybe that's just me though
Cheers,
Rob

Originally Posted by Paul Kimber

Cheers Rob,

That looks really good, just used the link for the EL sheet and it's not directing me to the actual product! Can you please place a direct link for all those interested in this mod?

if you look in the other thread links to EL panel are there

Originally Posted by Paul Kimber

Cheers Rob,

That looks really good, just used the link for the EL sheet and it's not directing me to the actual product! Can you please place a direct link for all those interested in this mod?

I did try, hope this might work. It's not coming up in the address bar other than the main home page.

If this does not go there, type into Conrads Quick search; EL Inverter and then goto page 4 of 11. There you will find the Inverter and different colour panels.

Suitable EL inverter
Product ID: 184005-I5

Suitable EL inverter
Product ID: 184005-I5

Originally Posted by robgt

Well done Rob, nice mod and an excellent write up.
Being a total noob to electronic messing-around-ery (that's a word!!) I would need clarification on point 8 above as to what should be soldered to what.
Maybe that's just me though
Cheers,
Rob

Have a look at the drawing i did near the end of the thread.

The 2 wires (that dont have a polarity as AC voltage) go from the EL panel to the Inverter. use a common negative through all the joints.

You are basically taking a live feed after the Tx switch, through your own switch, through a 5V reg, and onto the inverter.

Does that help?

Originally Posted by Rctintin

I did try, hope this might work. It's not coming up in the address bar other than the main home page.

If this does not go there, type into Conrads Quick search; EL Inverter and then goto page 4 of 11. There you will find the Inverter and different colour panels.

Suitable EL inverter
Product ID: 184005-I5

Suitable EL inverter
Product ID: 184005-I5

Spektrum DX7 backlight mod

Thats smart tintin

Does it cause any worry for future fixes with HH if you have any probs elswhere in the Tx and need to send it off,i know HH are very very good with after sales but you know what some companies are like with modified products

Tis very good though,nice one!

That's a great mod, with clear instructions and pics.

Makes me feel even more inadequate as there is completely no way I could do something like that without botching it up. Have not a clue with electronics etc.

something for competition pilots to be aware of........

Electrically modifying a tx in any way invalidates it's CE approval, so in theory this mod could cause your tx to be refused at a competition or indeed a fly-in. Just thought I'd mention it as whilst it's a superb mod I'd hate to see someone loose their competition place over it.

Good point Ash.