3MM SINGLE LED Backlighting Tutorial

CLICK HERE FOR THE DUAL LED 1.5MM TUTORIAL

This backlighting tutorial is designed to work for the Pro kits found here. The finished product can be found here.

Click the images to zoom in for a larger image. For ultra large images, go here.

This tutorial assumes you already know how to open your Game Boy, remove the screws holding in the front printed circuit board, and remove the circuit board from the case.

Please read through the whole tutorial before doing this. Everything is done sequentially and in a step-by-step order, but certain steps are reliant on others. If you don't read through beforehand you may end up with an unusable backlight!

Although this tutorial is designed for LED type backlight modules, many of these techniques can be applied to different backlighting technologies, such as EL panels. If you are using a different light source, feel free to interpret this tutorial a bit more loosely, especially regarding removal of the plastic housing around the LCD.

Parts List:
Wire cutters. A small pair will work better than a large pair, as you'll be snipping off component legs underneath your LCD.
Soldering iron
Solder
Shrink tubing, 3/16" works fine
Heat source for shrink tubing
Razor blade
Tri Wing screwdriver
Small phillips head and flat-headed screwdrivers. A jeweler's set is a great investment for modding.
Resistor. A 1/4 Watt 100 ohm is perfect for these backlight modules. if you are doing you own thing you will need to calculate your own resistances.
Backlight module (or other means of lighting if you are doing your own thing)
Optional - hot glue gun

Once you have your front PCB (printed circuit board) ready, remove the two screws holding the lower ribbon cable in place:

Carefully pry up the screen by inserting a small flat-headed screwdriver into the notch between the LCD (liquid crystal display) and plastic housing.

Remove the foam inserts. Now, depending on how you want to go about this next step, you will either be removing the reflective film on the back on the LCD or both the film and the rear polarized film. I highly recommend removing both and replacing the rear polarized film with a new one, as it's both easier to remove and generally results in a better looking LCD at the end due to all adhesive layers being removed. If you only remove the reflective film, there will still be an exposed layer of adhesive on the rear polarized film which will get progressively dirtier as you proceed. Additionally, if you end up having to scrape anything, it will show up as streaks in the adhesive. You will not have this problem if you remove both the polarized film AND reflective film.

Removing the rear layers of the LCD

Note: it might not hurt to try this out on a damaged LCD first if you have one!

Insert a razorblade onto a corner of the LCD. If you are only removing the rear reflective film, be sure not to go too deep! If you are removing the reflective film AND polarized film, you can be a bit less cautious and insert your razorblade between the glass panel and film. Now, using your razorblade as a lever, peel back a corner of your film(s). If your corner is a greenish tint, you still have the rear polzarized film attached. If it is a light gray, you have removed the rear polarizer as well. If you accidentally removed the polarizer and didn't intend to, remove the razorblade and try again on another corner of the LCD. You have three chances at this, as there are three exposed corners of the LCD, two of which are easier to start at, the third being on the top right of the screen and a bit difficult, and the fourth, at the lower right, completely inaccessible.

Once you have a corner peeled to a size large enough to provide a good grip, take your thumb and forefinger and slowly begin to peel the film off while stabilizing the LCD with your other hand. I find what works best is a twisting motion of sorts, which will result in the edges coming off instead of the film peeling towards the center. Dry fingers will help at this. DO NOT MOVE TOO FAST, you have no need to do this quickly, and you may end up damaging your LCD. Be cautious not to let the lower right corner snap off by lifting the LCD, then pressing it down against the plastic housing. If you are slow and deliberate, you will be fine.

OK, you now have a modified LCD consisting of a front polarized film and two sandwiched pieces of glass with liquid crystal between them. Now to replace your reflective film (and perhaps your rear polarized film too) with a light source! Take a pair of wire cutters and trim down the legs underneath your LCD. If you don't do this you may get pressure points on your screen once everything is finished. Try to have them lower than or equal to the remaining plastic housing.

COMPONENT REMOVAL AND MODULE PLACEMENT

Remove the resistor and zener diode indicated below. Remove the indicator LED as well, then form a connection between the two points where the LED was previously with a liberal amount of solder. It won't take too much, but it may take a few tries to get it to bridge correctly. Be careful not to burn a hole into the contrast knob with your soldering iron!

Flip over your PCB and press in the plastic tab holding in the left side of the plastic housing. Flip your PCB back over again.

Take a pair of wire cutters and snip off the left portion of the plastic housing. Throw this away. Place your backlight module underneath the LCD with the cathode (the shorter leg on the module,) closer to the top of the PCB, and the anode, (the long leg,) nearer the bottom of the PCB.

Place a portion of your shrink tubing (it may help to pre-shrink this section of the tubing) around the cathode leg and bend the leg up to the point pictured below. Solder it into place. On the second photo you can see I've already trimmed down the long leg on the backlight module. Your module leg should have a similar length after you are finished with your mod, but you don't need to do that quite yet.

Heat up the point shown below on your pcb and poke your resistor through the hole. You will probably want to add a bit of solder to this point now. Be sure to leave enough length on the resistors legs to reach over to the ANODE (or long leg) of the backlight module! (read ahead for more info on this step)

Place another length of shrink tubing around the resistor and shrink it down. Bend the resistor's leg around to reach the base of the ANODE leg and solder it into place as close to the module itself as possible. Too far out and it will not fit in the case. Now snip off the excess on the resistor and backlight module legs.

Optional: Add a new rear polarized film. Choose if you want your screen to be normal or inverted. A normal LCD will be tinted green, while an inverted LCD will be a dark blue. An inverted screen has some advantages and disadvantages.

Normal LCD:
Visible without light source turned on
Better visibility with some colors, mainly blue

Inverted LCD:
Very sleek looking. Inverting the rear polarized also gives a different final shade to some modules. Red will appear more rich on an inverted screen, and have an orange hue on a normal screen.
I personally find an inverted screen easier to use with LSDJ.

To invert your LCD, simply rotate the polarized film 90 degrees before inserting it underneath the glass! It's that simple. Normal, rotate it 90 degrees again. Some color LEDs look better or worse with a normal or inverted LCD. Test it out each way and decide which you like best.

Be sure any protective films are removed from your polarized film. If there is translucent plastic on your film, you can remove it easily by sticking a piece of tape to the corner of your film and pulling it back, repeating this step on both sides. If you film does not have protective layers of plastic, you don't need to do this. Now slide your polarized film between the glass and backlight module. Make sure it's centered and free of dirt, hair, smudges, etc. They will be very noticeable!

You should be all set. Plug your front PBCs ribbon cable into the rear PCB and power it on. Congratulations, you've backlit your LCD!

Extra tips and tricks

I highly recommend you trim down the plastic near the LED indicator position on the front part of the case. I find what works best is to squeeze this section with a pair of wire cutters and twist instead of cutting into it, if you do it right the whole thing will come off nicely, as seen below.

Once your module is installed, reinsert at least one of the screws for the lower ribbon cable. The one on the left is essential. Look at your LCD and make sure it lines up with the upper portion of the plastic housing. If it doesn't, you can twist the LCD a bit and secure it in place with a small amount of hot glue along the top. If you close up your case without aligning your LCD, it may be off center and will look unprofessional.