DMG uneven contrast (Page 1) - Nintendo Handhelds - Forums

1 Jan 27, 2016 11:47 am

Offline

Seattle, WA, USA

Can anyone advise how to fix this problem I'm having with this greyboy? I started to install a backlit screen and noticed that the contrast is all messed up. I have to crank the pot to see much of anything, and when I do, the contrast is not distributed evenly. There's too much being drawn vertically in areas where there are supposed to be many pixels, and not enough drawn where there are less supposed to be less pixels. Take a look at this video.

http://youtu.be/LxAs8oSxslg

Batteries are good, other screens (entire front PCB to be precise) work okay. Changing games only manifests the problem in slightly different ways depending on how many pixels are supposed to be drawn at a time. Heating the strip below the screen doesn't do anything useful - all the lines are there, they just aren't being drawn correctly.

Maybe caps are bad? Messed up ribbon?

Any advice would be appreciated. Thanks.

2 Jan 27, 2016 9:35 pm

brightwhitelightning

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Seattle, WA, USA

Bump

3 Jan 27, 2016 10:28 pm

Josh-Shmosh

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Cookeville, TN

You need a resistor on that backlight, bro. It should've come with one. Who'd you order from?
Also, I suggest you clip those wires wayyyy shorter. Otherwise they're a hassle to deal with when you're reassembling the system. They either end up getting in the way of a screwpost or they get stuck underneath the dpad/A/B buttons, keeping them from working properly once you have it put back together.

4 Jan 27, 2016 10:41 pm

Adzetko

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Ardèche, France

I'll go for the resistor issue too. When screen is acting weird like this, this may be the backlight eating too much to let the screen do what it should.

5 Jan 28, 2016 3:05 am

brightwhitelightning

Offline

Seattle, WA, USA

Yeah I can try throwing a resistor on there. Can't remember if the back light came with one - this is an old backlight I ordered from kitsch-bent probably two years ago. Never got around to actually installing it. I could have sworn a resistor was integrated but I can't really remember and they no longer offer this model on their site so I cannot check.

Any idea what resistor I should try? Preliminary research suggests a 100 ohm will do the trick. I am sure I have one laying around.

Also yes, I will cut the wires down eventually. Was just testing at this point.