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PostPosted: Sat Jun 01, 2013 10:31 am 
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After seeing some cool consolized gamegear projects I decided to tackle a consolized gameboy advance. I used the gba tv converter for this project:

Image

This converter is the most common tv adapter for the gba (it's also very cheap). And the best news is bacteria was nice enough to post the soldering pinout to bypass the ribbon cable which tends to lose connectivity very easily:

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This device uses a sony cxa2075 video encoder, nice. The device plugs itself into the gba power connections so you can power both the gba and tv converter from a single power supply which is also nice.

When I got my tv converter running I was presented with a s-video picture completely full of jailbars. After much pain and suffering I discovered that disconnecting the capacitor on the chroma output didn't disable chroma in s-video. To disable chroma I had to disconnect the caps for both chroma and composite video, which made me consider that they wired composite video and s-video together in the av cable. I snipped off the built in av cable and wired up my own s-video jack and sure enough the jailbars suddenly were 90% removed. To fix the other 10% of the jailbars I just weakened the chroma line until they completely went away since these jailbars are only on chroma. I also adjusted the luma output resistor to a better value. The s-video circuit in this was wired up like the application circuit from the datasheet which certainly isn't ideal so a little circuit mucking fixed all distortion. There was a lot of jailbar distortion at first it's like night and day compared to before. Here's the first build of it that's working as it should:

Image

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I need to buy a parts gameboy to harvest a cartridge slot so I can remotely wire the slot.

Consolized gba + home built devcart + marioland colorized romhack ftw!

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http://www.youtube.com/watch?v=JjcG0jn2Jr8&feature=youtu.be


Last edited by Drakon on Sun Jun 02, 2013 8:21 am, edited 1 time in total.

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PostPosted: Sat Jun 01, 2013 1:57 pm 
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Location: Seattle
What are you doing for input?
Why is the crystal (filter?) floating in space?
Any thoughts about a more permanent design?


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PostPosted: Sat Jun 01, 2013 7:27 pm 
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lidnariq wrote:
What are you doing for input?
Why is the crystal (filter?) floating in space?
Any thoughts about a more permanent design?

I'm going to straight wire the controller into a svga port. The floating crystal is because when I first wired it up I got heavy jailbars, I thought maybe the crystal was adding interference to a trace or few. Turns out the s-video and composite jacks were wired together by default which was giving it huge jailbars. Yes I'm building it into a case, installing a relocated cartridge slot, I was thinking of using a genesis 2 case.


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PostPosted: Sun Jun 02, 2013 11:20 am 
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I hope it's a spare Genesis 2 case. Be sure to post what your creation looks like when complete.

Personally I'll stick with the GameCube and GB Player.


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PostPosted: Sun Jun 02, 2013 9:19 pm 
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MottZilla wrote:
Personally I'll stick with the GameCube and GB Player.

But then you'll have to play Tilt 'n Tumble like this. :mrgreen:

Too bad I got rid of my GameCube. :( I was thinking of buying a GBA TV converter, but then realized I don't have a standard GBA.

Anyway, good work, Drakon! Image

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PostPosted: Sun Jun 02, 2013 11:57 pm 
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This homemade device won't exactly be any better for that one game.


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PostPosted: Mon Jun 03, 2013 12:10 am 
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Jedi QuestMaster wrote:
I was thinking of buying a GBA TV converter, but then realized I don't have a standard GBA.
If you're planning on building a soldered semipermanent rig like Drakon, that doesn't matter—the header is in the same order in both the plain and SP GBAs.

I bought one of the above pictured converters when they were new, and was not exactly thrilled. The fit was enough off that I found it far too easy to briefly disconnect the vampire LCD passthrough, or far worse, the power to the GBA itself. The moment the GC GBA player was available I switched to it. (The GBA player also upscales the GBA's 160p to almost-full-frame (400 lines of 480i?) instead of your choice of doubly-letterboxed subframe or a nearest-neighbor upscaled copy)


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