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In the year 2000, Ben Heckendorn built his first mod.
“Ben: We can rebuild it smaller, better, portable.”
Since then, he has continued his work helping those in need with creating new projects. If you have an idea you’d like to see built, why not send it to The Ben Heck Show.
“Ben: Hello and welcome back to The Ben Heck Show. In this show we are going ‘old school’ Ben Heck and building a small portable game system. In 1992 Sega released an add on for the Genesis console called the Sega CD, this allowed users to play games that CD ROM based so you contain much more user data and music than the cartridge based games, which would max out at about 4 megabytes of time. Anyway a lot of the games were FMV nonsense, like choose your own adventure stuff or Night Trap which actually I am fond of because I am big fan of cheesy movies.
But there were some diamonds in the rough, as well such as Japanese translations of Lunar The Silver Star, and Snatcher. A few years later, Sega released an all-in-one combo system that combined the Sega Genesis and the CD ROM system into one fairly small unit called The Sega CDX. So The Sega CDX will be our build today. I will dig one up, take it apart and try to make it portable. Let’s have at it.”
“Ben: I often get asked, where do you find these old game systems, and the answer is eBay. Just like anyone else basically. You find one that is not too outrageous - $829 what is it like five copies of Lunar The Silver Star? There has to be at least one copy of Lunar The Silver Star, yep there it is. Some of the RPG’s for the Sega are actually pretty good, it wasn’t all FMV crap games although those have a special place in my heart too.”
“Ben: Alright we got one in the mail, the Sega CDX. I have actually never seen one of these in person before, it’s a lot smaller than I expected actually. It’s got the Sega Genesis CD ROM circuitry, and of course the CD ROM drive as well. So it starts small and we should be able to make it smaller, hopefully. One thing that is kind of cool about this is you can put in 2-AA’s and actually use it as a portable CD player, too. It is always good to test something before you rip it apart, especially with older used equipment like this. That way you know that it was broken before you broke it. I have got this little 4 inch screen that I am going to use, and they are meant to run off 12-volts but it would be nice if you could run them off a lot of voltages, I am going to try 5-volt here.
Oh man, all these great crappy Sega CD games to try – which one should I test it with? This one is a soundtrack by Thomas Dolby of she blinded me with science fame. We don’t have audio hooked up, but this is the one I will use. Let’s see what happens – system on, yeah that boots pretty quick actually. Wow it’s like an interactive movie but with 6-bit color depth. Oh no, not digital pictures. We are in for a rocky ride. It’s got a bottom metal plate, wow that is some heavy duty shielding there. It is kind of hard to see, but this par right here is actually a separate circuit board – see this small line here. It appears to be the power regulator, we might be able to replace this board entirely – but we know what it does. Alright, I finely pried it apart. It appears to be two basic halves, right here you can see the two processors.
Sega had a 68-K Motorola, and the Sega CD ROM also had one. So the Sega CD ROM has coprocessors and you can see those here, so this is the brains of the unit. Then it would appear over here, this is probably going to be the CD drive assembly. I know it seems complicated, but remember we are talking about something from 1995. These are our two basic parts, a motherboard – CD ROM. So that is what we’ve got to work with.
“Ben: With The Sega CDX taken apart, the next step is to draw the parts into the computer. I came up with a basic shape here, which represents a circle which might be the CD, and the screen inside of it. Now it is important to know that a lot of times an LCD screen or the visible pixel area is not centered inside the frame, which you can see here – it isn’t. So you’ve actually got to center the visible pixel area to your object, not the whole screen module itself – see how that works there?
Which means, this part is going to be lopsided, you see how there is more excess stuff over here than over here - which also means you have to make your frame or casing bigger, if the screen was symmetrical you could probably make it that small but we have to make it at least this big to enclose the edges of it. So that is a common problem that I come across. We also do a side view which shows us the depth. On the screen here, we have all the basic parts for The Sega CDX drawn into the computer. You have a representation of the main motherboard which contains most of the processors, ha ha – most of the processors. The Sega CDX has a Motorola 68,000 main CPU, it has a secondary Motorola 68,000 for the CD ROM CPU and then of course has a Z-80 for the sound synthesis. So if you had The Sega Genesis plus the CD ROM plus the 32-X add on you would have a total of 5 processors - getting into Atari Jaguar territory there.
So we have our parts here arranged on the screen, which represents the main motherboard, the Fe-Rem motherboard and of course the CD itself. So we have that as a base reference, so what we started to do is make the case around that. So we need to find the minimum basic area around this – usually I use about a 1/16 inch as a reference point, so it will be a box about like that. I can show you what I have done here, I am going to have to kind of build it backwards – this represents the rear piece of the unit, as you can see it comes apart in two pieces here. You might wonder why do you do that – you see how this is a separate piece? The reason for that is we need to route an indentation here, like kind of a well to make sure the CD has enough room.
But then this piece down here is going to have these two little tabs for the battery and those are going to be on the inside. So if we are routing the well for the CD here, then we have to route battery tabs here, obviously we can route both sides but it is more difficult because you have to make a jig. It is easier just to make it two separate pieces, so you can route them just from one side each. Then we go down in our layers here and we have another layer. This layer as you can see is separated – flanks the outside and gives enough room for the CD ROM’s motherboard here. Then down here there is a large area for the battery we are going to use. We see another layer which is pretty much the same, and has these circles here.
The purpose of that is the machine is going to go in and drill a whole bunch of little holes so the unit has these nice retro grooves on it like most things did in the ‘80’s and ‘90’s for some reason. It’s like let’s make our electronics collect as much dust as possible. So here is another layer and as you can see there are some tabs here that will line up to the screw holes so we can mount the circuitry to this layer. And the final layer is the case layer, and at this point we are not looking at it from the back – we are looking at it from the front. It is important to make sure you are looking at things from the right angle when you are drawing them, because if you draw everything from the front view you might end up making a piece backwards – it might be mirrored the wrong way.
So here is our front view, we have our screen which is nonsymmetrical again, but since we are not putting it on top of the CD – you actually have a little more wiggle room with what to do. So we have our minimum size of the unit which is 5.5 x 8 inches. Then we make this shape around it for the screen to go in, so it looks like a design feature instead of a mistake, and then down here we have plenty of room for the controls our D-pad, mode, start, X, Y, Z, A, B, C – and also since we are working in primitive 2-D we have to do two different views for everything, at least two different views. So we also have a side view here where you see how all the components are going to stack in. Then down here, I don’t know if it is very obvious, but you can see the battery which is that thing right there, it fits up underneath and here are the tabs we talked about.
So on this piece we have to route that way, and on this piece we have to route that way. Once all the pieces are done we have to break them out so they can be routed. We do it in such a way to be kind of efficient, we have all the pieces the basically – an acrylic piece, half inch stuff, and then quarter inch stuff and that is pretty much all there is to it. Now these side walls, we broke these apart into pieces and the reason we do that is so that it takes less space to route. I mean full size it would look like that, but if we group them like that we can save at least 33% of our material.”
“Ben: When we redesign a part such as a CD ROM assembly in the computer, it is very helpful to make a physical printout of it. The reason for that is because any modern printer when you print something at 100% actual size and it fits within a piece of paper, the drawing will line up to the actual size of the object so you can set it on the paper and make sure you’ve got it right.”
“Ben: Controlling charge and discharge rate of lithium ion batteries in your build is critical. Battery controlling IC’s are easy to use and inexpensive and you can fit them into any circuit you need. Element 14 carries a huge selection of battery charging integrated circuits from all the top manufacturers, you can also get chargers for other types of batteries such as nickel-metal and nickel-cadmium – all at element 14. Board leveling components such as battery charging integrated circuits are very important for most projects, however don’t be put off by the complexity – if you need help you can go to the element 14 website and learn from the community, ask questions, get an answer and find what you need.”
“Ben: With the designs done, it is time to route out the parts to build the case. We are using a high-density PVC foam called Komatex
, it is easy to route and fairly strong. It is also easy to modify later on if our designs aren’t quite right. Next we cut the tabs to pull the parts loose from the sheet, we need these tabs since we don’t have a vacuum table to hold down the small parts – the face plate is flat with the inside routed out for parts. We have also routed our own game controls which insert into the case. We then move on to the parts cut from half inch plastic, such as the LCD frame. The CNC machine cleans out the inside to hold the CD and drills holes for the speakers.
, it is easy to route and fairly strong. It is also easy to modify later on if our designs aren’t quite right. Next we cut the tabs to pull the parts loose from the sheet, we need these tabs since we don’t have a vacuum table to hold down the small parts – the face plate is flat with the inside routed out for parts. We have also routed our own game controls which insert into the case. We then move on to the parts cut from half inch plastic, such as the LCD frame. The CNC machine cleans out the inside to hold the CD and drills holes for the speakers.The LCD requires more depth than the game controls, so we made it as a separate piece that snaps into the front of the unit. This allows us to keep as much of the unit as thin as possible and also makes things look more interesting. The half inch thick side walls are nested together to save us material. We export the tool-path from part-works and back to the CNC. After drilling the holes to make the dust collecting grooves, the machine cuts out the perimeter so we can remove the parts, nesting parts saves material and reduces waste. We then do a test to see if everything fits, side walls down first, and then the front layer – looks pretty good. Here come the quarter inch pieces for the CD ROM area. Let’s check to see how these fit on the back of the case. First we have layer four, then layer five, then a CD – voilá. Next we need to be sure the electronics fit inside, looks good – okay that fits, I think we are ready to start wiring the power.”
“Ben: Now it is time to put the circuits inside of this case. We are going to start with the button controls and we will also use this little circuit board to mount the R-regulator. So I have made marks where I am going to put the drill holes, so the next thing to do is to flip it around and look at it from the front. We are going to use magic marker – very precise I know, to mark off where to put the tack switches for all the buttons. Now I am using some surface mount tack switches here, I chose surface mount because they were smaller. A lot of stuff gets hard to find any more like the the through hole where the holes go through, but that doesn’t mean you should be afraid of surface mount – most surface mount stuff you can still solder in by hand, so what I am doing with these for instance is I am just putting then on a standard perforated circuit board that I got from Radio Shack and not reflowing them.
So I am just using a little bit of super glue to put them in place, then I will go back and put on some solder so they will connect to the circuit board using the copper pads. I am a surface mount robot, so now that we have all the buttons in, it is time to wire up the voltage regulator. What we are going to do is take a 7-volt lithium ion battery and step it up to the 12-volts required for The Sega CD ROM. Okay, I wired the step up regulator, using this diagram I got off the U-work website. I printed the pin-out on one side, and the application on the other to save the environment. So we’ve got this 7.9-volt camcorder battery, and we are going to hook it up to our circuit and see if we can get 12-volt out of it. So here is power input here.
Okay, I don’t know if you can see that on the multi-meter but we are getting 12-volt, now let’s see if it is enough to power The Sega CD ROM. Here we go. Okay, I am using a Sean Mullin CD in case something goes wrong - you know I don’t want to ruin any CD’s I care about. Ah yeah, here we go the screen pops up so we have stolen 5-volt to power the screen and it is running the CD application. It appears to be working.”
“Ben: The next thing we need to do is connect the original Genesis controller to the one that we built. Unfortunately we are using the 6-button model which complicates things. It is really much more complicated than a 3-button Genesis model. The circuitry to drive it is under a glop-top resin so we have to amputate this part of the board so we can use it on our own unit. This must be removed carefully so we can still see where the traces are meant to go. The next step is to remove the controller cable from our hacked up board.
We will add a header to this so it can be easily connected to the CDX’s motherboard. We count out how many connections we will need, nine for the controller, one for video, two for audio, plus an extra ground and an extra 5-volt. Next we check the connections on the cable using a multi-meter and swap the board over to our custom connector one pin at a time. You have to make sure this is right, because if it isn’t we will get confused easily. The CD ROM mechanism and driver board has been made into a single assembly by using screws and rubber washers on the three mounting points.
The LCD track time display has been removed. As for the main motherboard, we removed the cartridge slot, tilted the power supply up, and rotated several electrolytic capacitors sideways to give us more room. The game system components mount onto four screw posts on the back of the unit, and a power switch goes to the top. Along with game controls, video and audio are added to the header that connects the sides together. Our camcorder battery clips onto the bottom via some Molex terminals that have been repurposed for this job. The battery then connects the step up voltage regulator via another header. Again, it is important to build things you can take apart. Finally it is time for the squish test – seeing if both halves fit together with everything inside. Aha, they do. I had no doubts.”
“Jason: TSA is never going to go for this.”
“Ben: I’ve got the solution. You don’t need all this.”
“Jason: Hey.”
“Ben: All you need is this portable Sega CD system.”
“Jason: Oh.”
“Ben: What is this?”
“Jason: That is one of the greatest games ever made is what that is.”
“Ben: Yeah, Snatcher. Wow, look at this thing you could sell this on eBay for a great price.”
“Jason: I remember losing many hours to this game, back in the day. Alright for those of you unfamiliar with Snatcher, basically the game is Blade Runner except it is cool. Wow I’ve got plenty of space here for my extra knitting needles, cigarette lighters, and lithium ion batteries. I think I am all set for my trip.”
“Ben: Well Jones, my work here is done. I shall take my fee and be out of here, until next time.”
“Ben: That is all the time we have for today, in our next episode we will be attempting a high speed can cooler for when you absolutely, positively have to have a cold soda right now. We will see you then.”
The Ben Heck Show has been possible by our sponsors at element 14. For more information on all my projects and for a list of parts I used today, visit element14.com. We will see you next time.
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