WHITE LED-MOD 
This mod is taken from "
Hacking Video Game Consoles (c) " - Ben Heckendon.
Hacking a PSONE Screen.
In 2000 Sony released a redesigned Playstation 1 called the PSOne. And it had a clip-on screen available!
The PSOne sceen was meant to plug into the back of the PSOne and replicate the ports. By this, I mean you'd then plug the power jack into the screen, therby connecting it to the PSOne. Same with the audio/video jack. You can consider it a "pass-through" of sorts. You'd then have this little semiportable Playstation 1 unit.
I secretly think yhat both the PSOne ad the screen were built to cater to the whims of expermienters everywhere. At £35 for a 5" LCD screen, it's a steal! The screen can accept composite video input, making it useful for a variety of purposes.
First, be aware that the PSOne screen must be converted to use white LEDs to be of any use to us. You will need:
Three 3-mm T1 white LEDs (
www.digikey.com, part #CMD204UWC-ND)
One 10-ohm resistor (Radio Shack catalog #271-1101)
A small, rather blunt Phillips screwdriver (more on this in a bit—get it, "bit"?)
Some strands of standard-size ribbon cable.
Taking Apart the PSOne Screen
The first step in modifying this thing is, of course, to take it apart. The screws on this screen are sometimes hidden and a little sneaky... here's how to find them:
1. Use your knife to wedge up the edges of the white speaker covers—they're just glued in place. Once you've got a bit peeled up, pull it off the rest of the way with your tweezers. You'll find two screws under each speaker cover—remove them all.
2. Using your knife again, lift off the two little rubber screw covers near the top of the unit, just above the screen. This will reveal two more screws. Remove them, along with the three exposed screws at the bottom of the unit near the plugs.
NOTE: The screws holding the PSOne screen together have shallow groves in which to place your screwdriver. If your screwdriver is too pointy, it won't grip and will strip the screw head, making the screw even harder to remove. Use a fairly blunt-ended small screwdriver instead. Another key to removing screws like this is to push down harder when unscrewing them.
3. Use your fingernail or a flat-head screwdriver to peel the case open; there are tabs holding it on the sides and top. Set the rear plastic aside, and you'll see what looks like Figure 4-21. Remove the five indicated screws.
FIGURE 4-21:
4. Carefully flip the unit over, holding the loosened circuit board in your hand as shown in Figure 4-22. The screen is now loose and you'll want to avoid moving it around in order to protect the LCD's ribbon cable. Fold over the front plastic casing and then detach the four cable plugs, as shown in Figure 4-22.
FIGURE 4-22:
5. Set the speakers and the rear plug assembly aside for now. Unplug the two thick bulb wires coming off the inverter; they're pink and white. Flip the circuit board over, with the screen facing down (be sure it's set on something soft to avoid scratching it).
6. Look for the ribbon cable clamp on the back of the board, as seen in Figure 4-23. Place one edge of a thin flat-head screwdriver under the brown tab on one side. Slowly twist your screwdriver so that the edge of the screwdriver head lifts up the brown tab. The clamp will lift off.
FIGURE 4-23:
This kind of ribbon cable clamp is very easy to break. Take your time when opening it to avoid snapping off the white tabs on either side. If they do break, you can hot-glue the ribbon cable back in, but that's not a desirable scenario.
7. You can now remove the LCD and light assembly. Set the main circuit board aside for now. There's a metal shield around the screen that is held in place by eight tabs. Push a thin flat-head screwdriver under each tab, then pry it up to free the metal from the tab.
8. With all the tabs undone, carefully press against the screen with your thumbs and lift the side tabs with your other fingers to remove the metal shield, as shown in Figure 4-24.
FIGURE 4-24:
9. The LCD glass is now loose. Hold the front of the LCD screen facedown against your hand and slowly lift off the plastic light box. It is not glued in any way, so if it snags a bit, tilt or shift it sideways until it comes free—do not force it.
CAUTION: The LCD glass is very thin and fragile. If the corners of it break, which they can during this procedure or during the reattachment, the screen will be dead.
10. Once the lightbox is detached, set the LCD glass facedown on something very clean (if you haven't already) and place a clean sheet of paper over the back of it to protect it from dust.
11. Now let's go to the lightbox. It has five plastic tabs holding the front of it in place. Open these just like you did the tabs on the metal shield. Lift carefully to avoid snapping them off. (This won't ruin anything, but the screen might reassemble a little less tightly.)
12. You can now unfold the front plastic frame. Rotate the light box so that the front portion folds down, with the bulb plug to the upper left. You'll find a thin piece of light-diffusing plastic held in place by two tabs on the left. It's actually two pieces of plastic, so try to keep them together. Using your tweezers, remove this plastic and set it aside, covering it to keep it clean. You can hold it by the edges, but do not touch the main surface with your skin. Treat this thin plastic with as much care as you do the LCD itself.
NOTE: You are now inside the light box. Keep everything in it clean. Whenever possible, use your tweezers or knife instead of your fingers, which can rub off oils and other mammal-based debris. (Don't worry—I won't go so far as to suggest wearing a hair net.)
With the insides of the PSOne screen's lightbox breached, we can now install the white LEDs. Then we'll reassemble the light box and make the actual electrical connections for the mod as well.
1. Bend the three thin plastic strips up to reveal the bulb. Then use your tweezers to lift the bulb up from the right-hand side, tilting it toward the left. You can now pull out the bulb and the wires on the left.
2. Now it's time to insert some white LEDs! Make vertical slits in the sides of the light box plastic, as shown in Figure 4-25. These slits should be just wide enough for the LED leads and the space between them to fit through. (Remember to make a corresponding slit in the fold-down plastic frame for the upper right-hand slit.)
Figure 4-25:
3. Next, place three 3-mm white LEDs, as indicated in Figure 4-25, with the bulbs pointing in the direction of the arrows. Have the leads go through the slits and keep all of the long positive leads facing out, toward the screen side, in order to make wiring easier. Each LED should aim down the channel where the bulb once was. Once placed correctly, put some hot glue behind each LED (on its leads) to hold it. Watch out for strings of hot glue that might get on the screen.
4. With the LEDs in place, fold the three thin plastic strips back down over them, and then set the thin light-diffusing plastic back over the glass. Make sure the edges of the diffusing plastic are over the thin plastic strips. This is actually kind of tricky to do, especially without touching much of the diffuser plastic, but think of it as an exercise for developing manual dexterity!
5. With everything back the way it was, fold the plastic lid back up. If you placed the LEDs well inside the channels and didn't go too wild with the hot glue, the plastic lid will snap in place nicely. If it doesn't, you may have to go back and shave off some excess hot glue with a sharp X-Acto knife.
6. Hold the LCD glass by its edges and place it back onto the light box. Finally, snap the metal frame back over both the LCD and the light box.
7. Do not force the metal frame back over the LCD. Forcing the metal frame can break the glass. If it doesn't fit quite right, there may be an unlevel LED or too much hot glue. In addition, you may want to make some cuts in the metal frame to keep it farther away from the LED leads, as shown in Figure 4-26.
Figure 4-26
8. On the top of the main motherboard for the screen, you'll find a long transformer with six leads—two on one end, four on the other. Desolder all these leads to remove the transformer and kill the inverter circuit. This will avoid accidental shocks and also help to save power.
9. Place the screen assembly back onto the main board, sliding the ribbon cable through the slot. Push it into the ribbon cable clamp. Ensure that it's straight, level, and looks the way it did when you found it, and then press the clamp down with your finger.
10. Use a couple of small screws and nuts (size 4 at the hardware store) to temporarily secure the metal screen plate to the board until you're ready to use it in your portable. This keeps the screen from shifting around during handling. (You could also just set this thing on a shelf until you're ready to use it, I suppose.)
11. Flip to the back of the board, and look for the power regulator seen in Figure 4-27. Attach a wire to the left side lead. This will be your +5 volts for the white LEDs.
Figure 4-27:
12. Flip to the front of the board and place a piece of electric tape down as seen in Figure 4-28. Hot-glue a 10-ohm resistor on the tape and connect your +5 volt wire to one end of it.
Figure 4-28:
NOTE: Use more glue than shown in this picture, as the resistor can generate heat.
13. Connect the other end of the resistor to the long positive lead of each LED. Connect all the short negative LED leads to each other and then connect them to the ground spot indicated on Figure 4-29.
Figure 4-29:
Okay, the PSOne screen is ready to go! Reattach the cables and the speakers if you like, and you can then try it out using the 7.5-volt wall adapter that came with it. Otherwise, we'll talk more about hooking stuff up to this screen during the projects that use it.
If you somehow overload or fry the PSOne screen, you can jump a fuse to fix it, just like with most pocket TVs. The fuse is shown in Figure 4-30. Desolder it and put a bit of solder in its place if your screen stops working.
Figure 4-30:
The white-LED mod will make the screen darker than with its original bulb. You can trick the screen to get brighter by bypassing a small component on the back of the board with a thin bit of wire as shown in Figure 4-31.
It's just above the center of the board, where you'll see 10 little surface-mounted components in a row. You want to bypass the third one from the left, labeled CV30. Since it makes the screen a lot brighter, perhaps too bright for some people's taste, I'd suggest bypassing the part instead of removing it, as you may wish to change it back. (It's your call.)
Figure 4-31
