GG LED Mod (56k warning)

[Tibia]

Thanks! I'm still a little confused though (this is probably related to the number of years I've been away from physics, for which I apologize) - how did you come to the 33ohm value? Based on the the forward mA value of your LEDs or on something else? When I mess with the calculator at 3V to get a 33 ohm recommendation it needs a diode forward current of around 70-74 mA (or perhaps in the 50s for 2 diodes if I'm figuring that out right). The LEDs I have been looking at have much lower values (i.e. ~25 mA) and would therefore need a bigger resistor than 33 ohms (I think). Do I need to keep looking for higher current rated bulbs?

Well, I am pretty much self-taught, so my methods may need refining. I was told by a friend big into modding PCs to use a 33-ohm resistor when using LEDs on the 5V USB line, so I just picked those for this 5V application. Because they haven't blown immediately, the only ill effect is that they might not last as long as LEDs with a 50-75 ohm resistor. I think though, based on what you came up with, that I'll start using something with a higher rating, as it'd be nice to not worry about it ever again. lol

[xantufrog]

Well you certainly know more than I!

I did find this LED resistor calculator which gives fairly straightforward output for parallel circuits:
http://www.hebeiltd.com.cn/?p=zz.led.re ... calculator" onclick="window.open(this.href);return false;
It doesn't attempt to explain the more complicated 100ohm system the other site suggests though

It looks like for a 3V target in a common 20mA LED we'd want a 56 ohm resistor...

The radioshack LED discussed above by Gumby (I assume the 3.3V average/3.6V max, 25mA one) would want a 39 or 33 ohm resister depending on if you are shooting for 3.3 or 3.4 Volts.

[xantufrog]

So I completed this mod last night on one of my systems. I went with two 5mm 3.3V white LEDs from radioshack and a 39ohm resistor. Otherwise I followed Tibia's guidelines step by step.

It worked great for me, though I have made an observation: in my case, and this might just be the bulbs I used, the screen is either dim, or washed out. The brightness knob works fine, I just mean at a brightness level which would have rich colors with the CFL tube the LED-modded screen has very bland colors and a washed out look.

Has anyone else noticed this? I wonder if it is due to the light not being diffuse enough at dimmer levels. Perhaps I need to add a third bulb in the back of the system? Any thoughts?

I posted my own "guide" here so you can see some screen shots. The screens look alright with the room lights turned off as in these images, but side-by-side with an original system my modded one is amazingly dimmer or more washed out depending on the dial.

For those interested in doing this mod, Tibia's guide has far superior pictures and more of them, so I'd start (and probably end) there. I did post a few blurry shots not included in her guide, and suggested some alternatives such as heat shrink and epoxy and the like, so you could check out my post for some ideas.

Let me know what you guys think about the screen color/brightness issue!

[Tibia]

Using three LEDs will brighten it, but it will also look more washed out. When I used three, I also used the diffuser sheets from a dead pocket TV trimmed to fit the GG reflector.

I just now realized I don't have a pic of it, but my LEDs sit in the holders a bit differently. I pulled them all the way in, so that they're sitting in the very back of the holder. The holder's also filled with hot glue. Try just pulling them back so that the bulbs aren't actually in the reflector and see if that helps.

[xantufrog]

Thanks Tibia! Recessing the bulbs into the rubber caps did improve things. I have a little more light on the front of the screen and the bright spots are a little smaller as well!

I'm currently working with a separate reflector plate and a pair of back-mounted 130 degree LEDs to see if I can get more brightness on the screen while maintaining the color, but at the moment the bright spots are a killer. I'll post some screens for comparison when I have them.

[gumbyx84]

Not to play necromancer here, but has this project died or just been forgotten? I was trying to do the LCD mod on my own GG and was very interested in how this was going.

[Tibia]

It's a completed project, and works great. I did post a full tutorial to my livejournal. I just linked it here because I'm lazy like that. Here's the link again in case you missed it.

http://pipe-organ-wolf.livejournal.com/5865.html" onclick="window.open(this.href);return false;


I'm still experimenting with the stereo mod, though. I want to still retain the full functionality of the headphone jack, so I'm not going to tap straight into that. I've just not had much time for anything lately, so it's kinda just sitting in the back corner of the work bench.

[desertman123]

This is awesome! When i get a gamegear I'm so doing this!

[gumbyx84]

It's a completed project, and works great. I did post a full tutorial to my livejournal. I just linked it here because I'm lazy like that. Here's the link again in case you missed it.

http://pipe-organ-wolf.livejournal.com/5865.html" onclick="window.open(this.href);return false;


I'm still experimenting with the stereo mod, though. I want to still retain the full functionality of the headphone jack, so I'm not going to tap straight into that. I've just not had much time for anything lately, so it's kinda just sitting in the back corner of the work bench.

Ah ok. I didn't know that that was the end of it. I thought you were going to do more work on it. I still need to get off my butt and finish my own GG LED mod. A friend of mine was helping me do it, but then we got into a slight argument over the type of LEDs to use. He wanted wide-angle LEDs, which at radio-shack are ~$12 a piece, which I didn't want to spend on a "test" project. Then stuff at work got in the way and we never got to finish it.

That is one thing I wanted to ask you: Would using those wide-angle LEDs really make a difference, or would normal LEDs work if the right diffuser was used?

Edit: I need to read things better. See you are waiting to do the stereo mod. For me, getting the LEDs in will be enough for my first modding project.

[Tibia]

I now mount the LEDs in the fluorescent tube holders, so wide-angle would be useless to me. I've only ever used normal, as that's what I have, and I agree that $12 is a bit much to spend on an experiment. With the right diffuser, one wide-angle mounted in that reflector should do the job nicely. I've thought about trying something like that, but I really am satisfied with how I'm doing it now. I can do the mod in about fifteen minutes, with minimal parts, so doing it on commission for cheap is still worth my time using this arrangement.

[gumbyx84]

I now mount the LEDs in the fluorescent tube holders, so wide-angle would be useless to me. I've only ever used normal, as that's what I have, and I agree that $12 is a bit much to spend on an experiment. With the right diffuser, one wide-angle mounted in that reflector should do the job nicely. I've thought about trying something like that, but I really am satisfied with how I'm doing it now. I can do the mod in about fifteen minutes, with minimal parts, so doing it on commission for cheap is still worth my time using this arrangement.

Thanks for the info. I had a feeling that the wide-angle LEDs wouldn't be worth doing the way you ended up mounting them. Now I have proof I can show my friend/co-worker. I'm going to see if we can finish this up tomorrow (if our work loads are light) with the newest bulbs I bought (Viewing Angle 30 deg, 7000mcd Intensity). I might try doing it myself, but since I can't solder to save my life, I'll probably wait till he can help me.

Again, thanks for the info.

[eurddrue]

I did this mod and it looked terrible What LEDs do you recommend Tibia, because all of mine are too dull or colorful.

[Tibia]

They were a pack of 100 I got on e-Bay a while back. They came in a vaccuum sealed plastic bag without the specs printed on it, so I have no idea what the mcd or anything is.

[eurddrue]

They were a pack of 100 I got on e-Bay a while back. They came in a vaccuum sealed plastic bag without the specs printed on it, so I have no idea what the mcd or anything is.

There are some 10mm ones on rat shack I was looking at, do you know how big the holes are? I'd assume 10mm.

[gumbyx84]

They were a pack of 100 I got on e-Bay a while back. They came in a vaccuum sealed plastic bag without the specs printed on it, so I have no idea what the mcd or anything is.

There are some 10mm ones on rat shack I was looking at, do you know how big the holes are? I'd assume 10mm.

I believe they will be. I picked up some 10mm LEDs a while ago and they seemed to fit fine. I would recommend not getting the ultra-bright bulbs. They are a bit larger, so they won't fit in the holders. Also, they cause a noticeable bright spot on either side of the screen (again, from my own experience).