Screen too dark

[Chapel]

Little story before I get to my problem. Before risking a useful piece of electronics, I decided to see if I could make this little 10-in-1 Jakks Atari device into a portable. Well, after a few days of experimentation and waiting for my battery from batteryspace.com, I have finally hooked everything up.

At first, I was getting the problem Dr. Killgood described in a different thread and determined that my soldering on the ground was subpar. I fixed that solder joint and hooked up the battery once again. At first, I thought that I hadn't fixed anything, but then I realized that the screen was just very faint and if I looked hard enough at the right angle, I could see the Jakks game menu. So I am a step closer, but still a mile away.

I've heard about the LED mod (though I'm not exactly sure how to do it) being a possible way to lighten up a dark screen, but I was under the impression that this was just a way to save watthours. Is it possible that I may have another bad solder joint somewhere in the video output or would that present in some different way? (I would take a picture, but the screen is too dark to even see in the picture.)

The major components I am using are a 5" Zenith, Jakks Atari 10-in-1, a 7805 with 2 resistors so that it puts out 6V and a Li-ion battery rated 7.4V -- 2200mAh.

Any help with my little test project is appreciated.

[bacteria]

I know with the PSone screen that if you don't feed the screen its 5v (pin 12 on the connector) that the screen can be very dark - not sure if this is also true with the Zenith - may well be.

These cheap plug'n'play devices seem to need more juice than you would expect - they run off 4 x AA's (6v) as along as the batteries are strong, if they are not full power you get screen glitches - I found on the Intellivision one that there is a 4 x AA battery compartment, but the system doesn't work properly on 6v, but runs perfectly fine on over 7v!

[Dr. KillGood]

Isn't their a fuse that can be bypassed to make the screen brighter?

[Neildo_64]

Yes, but it makes the colors all washed out looking. Its like upping the gamma. Is there any light at all? If it is that dark, you probably broke the backlight somehow. If so, you need to either get a new backlight or LED mod it.

[Chapel]

I know with the PSone screen that if you don't feed the screen its 5v (pin 12 on the connector) that the screen can be very dark - not sure if this is also true with the Zenith - may well be.

These cheap plug'n'play devices seem to need more juice than you would expect - they run off 4 x AA's (6v) as along as the batteries are strong, if they are not full power you get screen glitches - I found on the Intellivision one that there is a 4 x AA battery compartment, but the system doesn't work properly on 6v, but runs perfectly fine on over 7v!

I'm feeding it 7.4v from the battery through the on board voltage regulator, the AC-DC adapter says that it outputs 7.5v (but there was a bit of controversy over that, maybe it actually outputs 13v?).

After a little bit of tinkering, I decided to open up the LCD itself. When playing it with a light shinning behind it played pretty well. That rules out the idea that the darkness is related to the voltage I am feeding to the Jakks. I guess that it is possible that I messed up something with the native screen light source (as it seemed to work fine when I first tested it). I didn't want to have to do the LED mod because it is my first project and I wanted to keep it simple, but just based on the results of this little test, I think I may have to.

Oh well, more battery life never hurt anyone.

[Chapel]

Yes, but it makes the colors all washed out looking. Its like upping the gamma. Is there any light at all? If it is that dark, you probably broke the backlight somehow. If so, you need to either get a new backlight or LED mod it.

Inspired by this post I poked around with a Voltmeter and realized that I wasn't getting any current through the part where the backlight plugs in. This means the end to my life long streak of never having accidentally broken anything from taking it apart . Oh well, LED mod ho!

Just to make sure I got it right, I just want to put two white LEDs that will turn on with the screen just off the side of the screen with some kind of white backing, right? If that's the case, I should be able to figure it out from there.

[lovablechevy]

Just to make sure I got it right, I just want to put two white LEDs that will turn on with the screen just off the side of the screen with some kind of white backing, right? If that's the case, I should be able to figure it out from there.

you'll want to use more than 2. 3 or 4 leds seems to be the most common mods around here. in fact, i believe that 4 is becoming much more popular than 3. some even use 6. the complaint with 3 is the lighting is too uneven and dark. so, 2 would be even worse. i find that using 6 gives it the same brightness as the original back light. but, it's all just personal preference.

and here's the how-to straight from ben's book!

[Chapel]

Just to make sure I got it right, I just want to put two white LEDs that will turn on with the screen just off the side of the screen with some kind of white backing, right? If that's the case, I should be able to figure it out from there.

you'll want to use more than 2. 3 or 4 leds seems to be the most common mods around here. in fact, i believe that 4 is becoming much more popular than 3. some even use 6. the complaint with 3 is the lighting is too uneven and dark. so, 2 would be even worse. i find that using 6 gives it the same brightness as the original back light. but, it's all just personal preference.

and here's the how-to straight from ben's book!

Thanks for the advice. That is pretty much how I figured it would go.