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J.Ivy

Sega Master system controller to 7800 mod

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But what about the Colecovision controllers on a 7800?? Will they work??

I believe all nine pin connecting controllers will work for the most part but still the same issue unless it has been modified will not recognize the few games that require the 7800 2nd button if they produce a different function in the game. So if you want to utilize a controller that plugs into the 7800 but is not specific to the 7800 (and has more than one button) SOME modification is required for 100% compatibility with all 7800 titles but the majority will work fine.

Edited by OldSchoolRetroGamer
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Very well then. Shame the joypad wasn't released in North America. It really wouldn't have hurt Atari to make the buttons on the joypad at least a little closer to each other.

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Well ive finished rewiring, wasnt too tough. but i admit that i was scared, just not wanting to screw it up! I didnt quite have the length to attach the resistors to the diode, so i added a short piece of wire, other than that, i followed the instructables link that i showed in my first post.

 

Now i just have to build another, so ive matched controllers. Guess ill be searching ebay again :)

 

2wh06d4.jpg

 

211q4ye.jpg

Edited by J.Ivy

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I well know what a diode does and how it functions. I was inquiring to it's purpose and placement in the schematic. The diagram I've been basing my calculations off of does not contain the diode although it is clearly present in the 7800 controller. I need to know where the diode is supposed to belong in the schematic:

post-10599-0-73575400-1402217871.jpeg

 

FYI, that Instructable article is terrible advice to butcher a funtional 7800 controller for two resistors and a diode when the necessary components are readily obtainable at Radioshack or elsewhere.

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"that Instructable article is terrible advice to butcher a funtional 7800 controller for two resistors and a diode when the necessary components are readily obtainable at Radioshack or elsewhere."

 

well this atari controller was a piece of junk, the interior plastic piece, under the joystick, that pressed the inner pcb buttons (up, down, left, right) was cracked and bent. I always wondered why it was so cruddy, i never thought to look inside it. I saved the remaining pieces, in case i need them to fix a stock controller one day, dont worry, im a pack rat :)

 

As to WHY this is built like this, i havent a clue. I just followed instructions.

 

The resistors are 620 ohms, so yes, they are available. I havent a clue as to what the diode would be. Im sure it could be found out though. Im thinking about buying some 10 foor db9 cords, so i could use those. It would be nice to have one long cord, rather than using cord extenders.

Edited by J.Ivy

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The resistors are 620 ohms, so yes, they are available. I havent a clue as to what the diode would be. Im sure it could be found out though. Im thinking about buying some 10 foor db9 cords, so i could use those. It would be nice to have one long cord, rather than using cord extenders.

Yeah the ten foot serial cables are the way to go. I used a 10 foot serial cable ($3 online) with my current Atari Joystick (built in paddles). I plan on doing another two-in-one joystick with SMS/7800 functionality with a switch selector. Important to note while serial cables will work well on Atari consoles, the metallic boots tend to be too large and bulky to fit in Sega and other console brands. Also some of the 3rd party extension cables (which work great with other 9-pin systems) tend to have sharper angled corners compared to the rounder D-9 serial headers. As a result I have found that the 3rd party molded rubber "Sega Genesis" extension cables tend not to have a proper fit with the metallic D9 connectors. Although they do fit enough to make a connection you may find the connection somewhat unsecure. Also be advised the 15-pin plugs found in Famicom, 5200, and Neo-Geo will not work with the 15-pin metallic "PC-joystick" boots because the pins are recessed too deeply. All three consoles which share the 15-pin connectors as well as the PC joystick standard use completely incompatible pinouts and you may damage something if you start plugging accessories that don't match, say for instance a Neo Geo stick into a 5200 or Famicom. Don't do it.

 

IMO a diode is a diode for the most part. Nothing inherently special about them. Your main concern is connecting them with correct polarity since they act like a one way street for current flow. All silicone diodes are going to be between .6-.8v forward voltage drop across the diode junction. The internal forward bias impedance is going to be completely negligible and the reverse bias impedance will be astronomically high. While there are special purpose diodes like Zenier, Germanium, or LEDs that emit various wavelengths of light, most all silicon diodes will behave identically in low voltage applications. You could even use one of those giant rectifier diodes rated for 1000v if you wanted, or a tiny one; it really doesn't matter. Radio Shack sells the small black can diodes with the silver stripe in two packs, or you can buy a baggie with a dozen tiny orange ones for the same $2-something price. Judging by the way the schematic works, the exact resistor value probably doesn't matter much either. If you an't source the 560s, you could probably sub anything between 470 ohms to 680 and it would work fine. Over the years Radio Shack has cut back on the selection of parts values. Used to you could find finer range of values like E12; not they are cutting back and most components are only available in limited ranges, for example only the E6 value resistors are commonly stocked (100, 1.50, 220, 330, 470, 680, 1k etc), and capacitors seem to only be stocked in E3 range (1, 2.2, 4.7, 10 etc) or even E1 decades (1, 10, 100...). With their focus on cell phones and gimmicky tech gadgets, it would not surprise me if Radio shack discontinues the parts bin entirely in a few years. It will be a sad day for the hobbiest when that happens.

Edited by stardust4ever

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I just got a SMS controller off ebay to send out for a 7800 mod, now I don't think I will. It's strange because I remember playing the SMS years ago and the controller functioning perfectly... I don't know if it's because it's old and probably been sitting for a while, but the one I bought is terrible. The buttons work, but the D pad is whack. I press right, It goes right and down or up.... same with left. I just can't win. :( As much as I DONT want to get an NES controller, I think I may have to because those truly are the best I've used for a game system.

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The Dpad is a giant square with points furthest away where the diagonals are. The Nintendo Dpad is actually circular underneath but the magic in how it works is by pressing on a thin strip in the for cardinal directions, for example when pressing right, very little pressure is in the up or down directions. With the square Sega joypad, you're resting your thumb on the edge so if your finger is in the slightest off center, you'll slide the thing into a corner and activate the diagonal. In an exploration game where your character moves in 8 directions, you could still controll it, but a sidescrolling platformer, action, or fighting game where diagonals cause a different behavior to strictly left or right, it could be a deal breaker. IMO Sega largely fixed these issues with their Genesis pad. The Dpad circle is exposed instead of recessed like NES/SNES, but you've got the molded cross which provides a tactile response in that you know you're hitting a single direction like right strait on instead of right and possible up or down.

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Perhaps the pcb board has some corrosion or dirt in it? dissasemble and clean the exposed copper bits with a q-tip and rubbing alcohol. Thats how i clean the end on cartridge games and they usually make great contact/work after that.

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Yeah, already disassembled it. Everything is 5X5... I have to agree with stardust, Maybe back in the day when my fingers where smaller it worked better... or maybe I just didn't play any SMS games that required the precision needed. The Genesis controller did get it right. However, the buttons used to stick... at least with me they did. Looking back and even today when I play my Famicom with Everdrive, the controller is flawless.

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Bump. Just wanted to say if you need to convert a controller, I'd recommend using the NES instead. There is a wonderful YT tutorial I used. They said to use a 620 ohm resistor. Well Radio Shack doesn't stock 620 ohm, so I subbed 560 ohm resistors instead. 680 ohm should also work. I used a Retrobit Genesis extension cable since it's more solid than cheap clone cables and has roughly the same girth as a stock NES controller cord. The extension cables are 6 ft but I whacked a couple inches off when I modded it so the actual cable length from the finished mod is closer to 5 ft, still longer than a stock 7800 Europad. I also inked out the Nintendo logo and added my own Atari logo with some black and silver Sharpies, so I can easily tell it apart from my NES controllers:

post-33189-0-08114100-1405187544_thumb.jpg

 

Youtube video:

https://www.youtube.com/watch?v=FQbokBHvQXA

Diagrams showing what to cut and where to wire the components are at the end of the video. Be sure to pause for these.

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I'm going to have to agree with this... definitely go with an NES pad conversion for the 7800. The SMS pad would LOOK better and go with the 700 better, but the controller isn't top notch like the NES one.

 

I actually decided to hold off on a pad mod for now. I'm going to attempt to change the dome switches in a proline to see if it makes it a little better.

Edited by 7800

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Best to worst:

NES pad > Genesis 3-button >> SMS pad >>> 7800 Europad

 

Genny/MD 3-button also works great for 2600, but if you mod it to support 2-button 7800 games, you'll lose compatability with SMS/Genesis and select 2600 homebrews that read the "C" button.

 

Also what's not to love about the NES pad? It's got two shiny red buttons to match the Europad, and gray trim that sort of matches the crappy Euro Dpad in color. If you think the SMS Dpad is bad about hitting unintended diagonals, on the 7800 Dpad it is nigh impossible not to hit them. I had so many cheap deaths playing Donkey Kong 7800 with the Europad, it isn't funny. Mario absolutely refuses to climb ladders if you activate a diagonal.

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Dk and pac man. I use a stick. Ya gotta know there are some days you dont need to be on the pad.

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Dk and pac man. I use a stick. Ya gotta know there are some days you dont need to be on the pad.

 

It's a work in progress. Waiting for paint to dry sucks...

post-33189-0-13366600-1405190453.jpg

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I'd had the Axe mod this dogbone for me, the dogbone wasn't working do to a broken cable so I've thought this could be a good 7800 game pad.

post-2841-0-67897200-1405380896_thumb.jpg

Edited by walter_J64bit

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I'd had the Axe mod this dogbone for me, the dogbone wasn't working do to a broken cable so I've thought this could be a good 7800 game pad.

Wow, I forgot about that design. That would be even better if one wanted to delete the start select buttons, fill in the holes, and repaint to match the 7800.

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Wow, I forgot about that design. That would be even better if one wanted to delete the start select buttons, fill in the holes, and repaint to match the 7800.

 

Have start and select be buttons 1 & 2 also so they have a useful function. Might as well keep them.

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Interesting idea, but why would anyone need 2 sets of fire buttons on a 7800 controller?

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Have start and select be buttons 1 & 2 also so they have a useful function. Might as well keep them.

You know what if I had the know how the start and select be buttons could be set up for rapid fire.

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Have start and select be buttons 1 & 2 also so they have a useful function. Might as well keep them.

Start and Select buttons are useless on a 7800 mod. Mine are disconnected. You could remove the buttons but it would look odd on a stock NES. The Dogbone will be much harder to mod due to limited space inside as well as surface mount instead of through-hole components. I also have a Dogbone with a damaged cable that I had toyed with the idea of doing a USB mod, but now I think I will just restore it with the 8 foot cable I pulled from my other NES controller mod. Whatever you decide to do with it, I wish you luck.

 

=======

 

I have also devised an ingenious little schematic for my arcade controller that will use dual-ganged DPDT switches in the back. This will allow the user to swap between SMS and 7800 operating modes. I'm also adding 10k pullup resistors to paddle pins 5 and 9 which will not effect 7800 or SMS operation but enable 2600 homebrews that read the extra Genesis buttons. The diode prevents Genesis/SMS "Select" output line (which is also Atari VCC) from draining current and pulling button inputs low.

post-33189-0-57603000-1405472776_thumb.jpg

Edited by stardust4ever

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Considering one of the forum members added NES controller ports to his 7800 a few years ago, what about adding Atari [sTe/Falcon/Jaguar] Enhanced Joystick Ports to the 7800? It would probably require some serious soldering to also enabled Pause and Reset to be enabled through the JagPads - not to mention assigning the difficulty switches to one of the extra buttons] but I'd rather use either version of the JagPads on the 7800 [and have both fire buttons work unlike the adapter cable Best Electronics sells currently] than a modded NES or Sega controller...

Edited by Lynxpro

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