Hi,

Gaining experience from the Futaba T7C Dark Display Issue - I embarked on a journey to get one of my old Futaba T6 EXAP transmitter Dark Display issue to be sorted. Pictures speaks more than words, so will try and add as many, work in progress pictures as possible.

This was the condition of the display panel.

Started Dismantling the Tx.

Slowly pulled out the rear side Polarizer film.

And then the front side Polarizer film.

My initial plan of action was to do a minimal operation and replace the polarizer film, having the display panel attached to the PCB. But upon closer observation, there was still one more layer of the polarizer film that was stuck to the rear display panel. So decided to go all out and pull out the display panel from the PCB. This was a cumbersome process and had to be handled very carefully and slowly. Finally after about 45 minutes of struggle was able to detach the display panel from the PCB without causing damage to the PCB circuits. 

Then cleaned both the surfaces with IPA to remove the old glue residues and got it to the level of my liking.

And by the way, removing the multilegged display panel was not easy at all. Had to use a hack to de-solder the legs all at once. Took a small copper wire and soldered it connecting all the legs together thereby having a one continuous soldering beam which I was able to heat it with the soldering iron and was able to pull out the legs from the PCB.

@Flyboys

Excellent tutorial, sir!

It was very busy day for me, hence not much got done. However managed to cut the Polarizer film to size for both the front and rear of the display panel. Then got the white reflective sheet also cut to size.

Please note the cutting angle of the Polarizer film. One rectangle piece is cut on the horizontal axis of the sheet and the other on the vertical axis. If we cut both the sheets in the same angle, we will end up again with a dark display. We need to spend some time and play around with the polarizer film to understand which 2 sides gives us the maximum clarity in display and cut accordingly.

After couple of attempts and discarding few polarizer sheets  was able to install the polarizer film without any air bubbles on the screen.

And finally attached the white reflective sheet at the rear end using a cellophane tape. Now the display panel looks bright and good. 

@Flyboys

Polariser film is self adhesive?

A4 size is quite expensive (on Amazon)

Are smaller pieces available anywhere?

Great work TA B👍

Hi Sir,

Yes, Polarizer film is self adhesive.

The stuff available on Amazon is mostly expensive. That why I suggested to check out in electronics / mobile phones market.

Just now visited this site mobilepartswala.com and you should be able to pick it up from them. Ask for polarizer for LCD (there is a different polarizer for LED screen)

Here you go with the update:

Finally the Display panel is back on the Transmitter and here is how it looks.

Sharing the Before and After pictures for your reference.

Hi All,

For some of you the process shown in the above thread might be overwhelming.

Let me explain a simpler way to go about.

Last year, one of our aeromodelling friend brought his T6 EXA with dark display to be sorted. That was when I was venturing into finding out the dark display issue and its solutions. When I opened the transmitter and was examining the display unit, I saw that the sliver colored sticker at the back of the display had lost its original color and was not reflective any more - that's why we were getting a dark display.(attached picture) I was scared to remove the display unit from the PCB hence told my colleague that I will try a shortcut (without replacing the polarizer film) and the outcome might not be as good as new, but he might be able to view the display panel with much more comfort.

So I gently pulled out the silver back sticker and replaced it with a reflective aluminum sticker. At the first go I tried pasting the reflective sticker to the back of the panel. But the adhesive from the sticker gave a nasty finish to the display and hence removed it. Then I cut a reflective sticker to the exact size of the display and gently inserted it to the back side of the display panel and then pasted the sheet with cellophane tape to the display panel.

Eureka. We got the display back in action and was very much legible to view.

Yesterday in the airfield I saw that transmitter and I was reminded of the shortcut that I have used in the past. That friend has also gone through this particular thread and I asked him if he wants his display to be made as good as new, but he said that he was very happy with the shortcut done earlier as his display is very legible to view.

Disclaimer: This trick will work as long as the polarizer film at the back of the display panel has not deformed. You just need to peel off the silver sticker alone and replace with a reflective material.

P.S: Today I got another T7C Tx and did this simple swap display restoration. Will post the picture of the same in the other thread.