Recapping and Consolizing a Game Gear (WIP)

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Ziggy
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Re: Recapping and Consolizing a Game Gear

Post by Ziggy »

I finally got the GGTV installed!

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Now I'm very near completion. I think all I really have left is to installed the controller mod board, hookup the multi AV output, and a few other minor things (trimming the case for fitments issues, install power on LED, tidying up everything).

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Ziggy
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Re: Recapping and Consolizing a Game Gear (WIP)

Post by Ziggy »

I hit a minor snag, but I've made progress anyway.

I started to install the controller mod board. First I soldered all of the wires to the GG motherboard, then I wanted to test it before going any further. And the GG was dead LOL. I was pretty annoyed, because it was only a few wires, and I was sure I didn't have any solder bridges or anything that might be causing shorts. So I wasted some time with the multimeter checking for shorts and confirming the correct voltage at a few spots. Seemingly nothing was wrong, until I noticed that the pixel clock signal to the TV out board is extremely sensitive. The installation notes mention that you should keep it away from all of the other signals because it might cause graphical interference in some games. But that's inside of the GG, with shielding. This console shell has no shielding, and I have it literally right in front of a CRT for testing. So at best I get loads of interference. I think I have to replace that one signal wire with a shielded wire. I currently don't have any single conductor shielded wire on hand (at least not anything that isn't big and chunky like salvaging the wire from an AV cable) so I ordered some. Hopefully that'll take care of the issue.

In the meantime, I decided to work more on the AV output. I finally put together the concoction, and it seems like it's gonna work out well.

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The bond between the PCB and the copper clad is very strong. In fact I think the weak link is the substrate of the copper clad. But it all seems super solid. Now I just have to add nuts and bolts, but I'm still decided if four (one in each corner) is overkill or if I should just do two. I suppose I could add two and test it, then add another two if I feel it's warranted.

A minor thing with the AV PCB that I designed, the labeling is all wrong. I used a generic footprint for the mini-DIN socket, and it was numbered. I (wrongly) assumed that the numbers corresponded to the standard numbering you usually see for the female socket, but that's not the case. So I'll have to go at it with the multimeter and pen and paper the pinout. A little annoying since I put some of them in a certain order, like RGB being next to each other. But not a big deal in the grand scheme of things.

edit: So as it turns out, I didn't goof, there was an error with the footprint that I found online. But I suppose that's what I get for not double checking everything for some random footprint I grabbed.
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opa
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Re: Recapping and Consolizing a Game Gear (WIP)

Post by opa »

I haven't read every post (so I may have missed it) but does the tv mod fill the whole screen or is it the size of the box like in the pic of ecco the dolphin you posted?

Also, what controllers does this support?
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Ziggy
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Re: Recapping and Consolizing a Game Gear (WIP)

Post by Ziggy »

opa wrote: Tue May 07, 2024 1:11 pm I haven't read every post (so I may have missed it) but does the tv mod fill the whole screen or is it the size of the box like in the pic of ecco the dolphin you posted?

Also, what controllers does this support?
https://etim.net.au/ggtv/ggtv.htm wrote:When playing Sega Master System games (with a cartridge adapter) the Game Gear compresses the video signal to make it fit into the internal LCD screen. This compressed video is not compatible with this output board. The compression can be disabled by connecting point T10 to +5v (logic high). In this state, the video will no longer display on the internal LCD screen but a good, full screen picture will output from the board. A switch or pin on the video connector can be used to select whether SMS games render properly on the internal screen or video output. Game Gear games will have a large border (see picture below) and this is unchanged by the state of T10.
If I understand correctly, SMS games (via an adapter) will be full screen but GG games will not be full screen. Although if you are using a scaler, you could always zoom in.

The controller port mod support 3 and 6 button Genesis / Mega Drive controllers.
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Re: Recapping and Consolizing a Game Gear (WIP)

Post by Ziggy »

Ugh, so I have a sort of non-update update.

So when I initially wired up the GGTV, I had all of the wires excessively long. When I was testing it, I had some interference in the video signal but I knew it was probably because the wires were long and also because the instructions say to keep the pixel clock signal away from the other signals. So after testing to confirm that it worked, I then shortened all of the wires to get a neater install inside the case. But the problem with the video interference didn't go away. In fact, it was getting worse. I know that there is no shielding in this consolized case, and also I have it right in front of a CRT when testing so that probably doesn't help. But moving it further from the TV didn't seem to do anything. And I even resorted to swapping out the pixel clock signal wire for a shielded one, but that surprisingly seemingly made it worse!

It was also intermittently NOT working at all. I wasn't getting any video or audio output. At this point I was thinking there's a problem with the Game Gear main board. Nothing I did seemed to help. Sometimes it would work (still with video interference) and sometimes I would get no audio or video. And I actually replaced a cap on the GGTV board just to be sure the issue wasn't there. Then I was re-reading the instructions for the GGTV install and remembered that it said to be sure to ground the GGTV on both sides of the board. So I wired the additional ground and it seems to work consistently now. But still with the interference.

So what's the deal with the interference? I'm thinking the signal lines to the GGTV might still be too long. So I suppose I'm taking a mental break from it right now (which is always a good idea to avoid having a project get deeply embedded into the drywall LOL). But I think the next thing I will do is shorten the signal wires and see if that helps.

Of course, not having an oscilloscope really doesn't help. I can probe with a multi meter, but that isn't always useful. Basically, I can only tell if something is on or off, but not really what it's doing. This is why I replaced a cap on the GGTV, because with a multi meter you can't really tell if an NTSC composite signal is there or not, just if there's voltage or not. Not that if I had a scope I would all of a sudden be an expert, I would really have to learn to use one first. Or more accurately, learn what signals I'm looking for and what those signals should look like. So it's kinda like if I wanted to go to Mars. I would think, if only I had a space ship then I could go to Mars. But in reality, having a space ship wouldn't automatically or instantly give me the ability to travel to Mars.

The problem with not having a scope can obviously be easily solved by buying a scope. The problem with that, for me, is that the cost for a decent one has always been hard to justify with this just being a hobby of mine. And really, if this was the ONLY hobby of mine it would be easier to justify the cost of one. But my problem is having too many hobbies, and that makes it hard to budget the money between so many different things. I was recently posting on NesDev to see if I could get away with a cheaper budget scope. But I think I came to the same conclusion that I always do when I Google around about it, that there's a certain minimum that I would need and anything less might be a waste of money in the long run.

All that said, and to stop ranting... I think I'm going to bite the bullet and finally get a scope. I feel like I kinda need one for this, otherwise everything is a guessing game with trial and error. I could shorten those signal lines, purely on a guess, and if it works it's just a happy coincidence. And if it doesn't, well I'll have no real idea why. What I think would be a better idea is wait to get a scope, so I can see what those data lines look like right now. Then shorten them, and see what they look like then. If they look the same, then I know for certain that wasn't the problem. If they look different but I still have the interference, then I may be onto something. Or at least, I can go from there.
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