Help requested to overclock a PAL Sega Megadrive 2 Console.

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Help requested to overclock a PAL Sega Megadrive 2 Console.

Post by wigsplitta »

My brother very kindly produced this little beauty for my birthday pressie:-
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Very cool indeed, and works like a treat. Added a 50/60hz switch and Japanese/eng switch. All cool.

Lastly I wanted to add a couple of switches to overclock the processor and eliminate the slowdown that is so evident on some games. I've found a couple of websites that explain it fully, but it only appears to cover a Megadrive 1, and one of the details is incorrect.

http://translate.google.com/translate?p ... ry_state0=

It states that the processor needs pins 15 and 17 connected. Pin 15 I believe to be correct, but pin 17 was not. It had no effect, and did not stop the graphics process. With a bit of trial and error, i discovered that pin 19 was the one to use.

There is also a video, but this uses an american genesis, so this might also be a reason why mine doesn't work the same.
http://www.youtube.com/watch?v=zuHkq8uvnLc

So, the problem that I am seeing is that i have connected the two switches to the corresponding points on the cartridge pins, processor and earth. I can flick the 'halt' switch on and off and it continues to work fine, but if i flick the 'halt' switch and change the other switch to look at pin 15(13.4mhz) and then unflick the 'halt' switch, then the game freezes. I have checked and re-checked all the solder points, and there is no bridging or shorting. I did not cut the track of pin 15 from the processor, as you can see in the pix below, i unsolderd the leg from the board instead.

Has anyone ever done this themselve on a megdrive 2? Possibly I am thinking that the processor doesn't allow it on this model, or maybe the pin of the cartridge port has been changed?

Any thoughts would be greatly appreciated :D

Cartridge port - pins 15 (orange) and 19 (yellow):-
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Processor - pins 15 (detatched from circuit board) and 19 :-
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Re: Help requested to overclock a PAL Sega Megadrive 2 Console.

Post by yosai »

Yo, **** it up Yella.
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Re: Help requested to overclock a PAL Sega Megadrive 2 Conso

Post by Porl »

I know this is dredging up a bit of an old topic but I'm really interested in the JAMMA megadrive 2 you have and also your attempts at overclocking it. I have overclocked a Megadrive 1 and i'm about to start another one either tonight or tomorrow night but I've been wanting to do my spare Megadrive 2 as well but I just couldn't follow the explination on the video. I have to see the thing really to get it into my head :awe:

Its cool to see how you've wired your switches from the top photo. The only thing I can think of that might help is that with overclocking the MD1 you have to keep all your wires as short as possible from the processor, your new crystal (which I think you don't need in the MD2 overclock) and your switches otherwise it makes the overclock go all weird or not work. :? It might help to trim your wires right down and move the switches into a lot closer position to the processor etc? So the wire length / resistance isn't tweaking the processor out.

Thats a very cool beast by the way! :awe:

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Re: Help requested to overclock a PAL Sega Megadrive 2 Conso

Post by Porl »

I'm still messing about with my Mega Drives and I'm currently pimping out a MK1 as much as I can short of Neptune-izing it (all the video mods, language, 50 / 60mhz and overclocking) and when I left the house this morning it got me thinking that you could possibly just overclock the Model 2 in the same way as the Model 1 if you know which points on the CPU to solder too.

I did a quick google search this morning and must have used some different search terms because I found this video, not a step-by-step video but it shows that he's done it the way I was thinking. Making a 10MHz crystal package and taping it to the top of the CPU and soldering to pin 15 on the CPU.

http://www.youtube.com/watch?v=Cvl5Vhtsodk

As it doesn't show about the making of the Overclock package which goes on top I thought I'd link to the video tutorial I used for my Model 1 which worked an absolute treat! :D

http://www.damomonster.com/Mod_Pages/SegaMegaDrive.html

So in theory, if you combine the Model 1 Overclock mod to the new pin locations from the other video it should work. :awe:

Once I've finished my Model 1 mods Im going to try out the Model 2 overclock and if it works I'll let you know.

I hope that helps

cheers

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Re: Help requested to overclock a PAL Sega Megadrive 2 Conso

Post by Porl »

Hey wigsplitta,

I've managed to successfully overclock the model 2 mega drive! :awe: it is possible but I did it a different way to the way you originally did it. I did it the 10mhz crystal package way and it works.

I've taken some photos for you to see how to do it. :)

First of all you need to make the 10mhz switchable package following the brilliant video from http://www.damomonster.com/Mod_Pages/SegaMegaDrive.html"

Once you've made this then you need to find Pin 15 on the processor and gently heat it and pull it out using a pick tool or something similar. Once you've done that you solder a short wire (under 3 inches) to pin 15 and another one to the solder pad that pin 15 was soldered too.

Image
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You then wire the 2 wires from the processor to the DPDT switch along with the 10mhz clock wire from the overclock package.

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In the photo you can see the 10mhz clock line (blue), the Pin 15 wire (orange) and the stock 7mhz clock line (solder pad) (green)

You then need to hook up the power +5v for the LED and find a ground point. I used the 2 capacitors around the processor for this. I tapped the capacitor on the left for the ground (white and orange wire) and the capacitor on the right for the +5v (orange wire). Keeps all the wiring etc pretty short.

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And once you've tested it then hot glue the Pin 15 area to make sure no accidental wire tug takes the pin off the processor or takes the solder pad up.

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That's pretty much it, you switch to one side of the DPDT and get a red LED and your switched to stock 7mhz. Switch over and the light goes green and your overclocked 10mhz. :)

I've also made a video showing it in action. The megadrive 2 I did the overclock on looks a bit of a mess because I had to de-neptune it. So had to put a cartridge slot back on, put the A/V port back on and hooked the 50/60hz and Eng/Japanese switches back up.



If you need any help modding your Jammadrive 2 up let me know. 8-)

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Re: Help requested to overclock a PAL Sega Megadrive 2 Conso

Post by dotty »

did you consider the switchless mod for MD?

http://www.dforce3000.de/?uid=12"

Cheers,
D
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Re: Help requested to overclock a PAL Sega Megadrive 2 Conso

Post by Porl »

Hi Dotty,

Yeah I've considered doing the switchless mods when I've read through the tutorials but I haven't had a go at them yet. Not had the chips but I think you need Hex inverters?

They do look cool to do though. Leaving your console looking all stock and stealth 8-)


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Re: Help requested to overclock a PAL Sega Megadrive 2 Conso

Post by dotty »

The one from d4s does not have the need for an inverter :shh:
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Re: Help requested to overclock a PAL Sega Megadrive 2 Conso

Post by wigsplitta »

Porl - Thank you for the info, I still haven't got round to trying this yet, but I think I've got a bit more free time in the new year, so I'm gonna have a go :awe:
Will also have a look at the switchless mod too, but I quite like the fun of soldering switches and wires. My MD already looks like something out of a homebrew Tardis, so a few more wires won't hurt! :lol:
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Re: Help requested to overclock a PAL Sega Megadrive 2 Conso

Post by NaokiS »

Mega Drive to JAMMA? Gotta try that one day myself.
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Re: Help requested to overclock a PAL Sega Megadrive 2 Conso

Post by Porl »

wigsplitta wrote:Porl - Thank you for the info, I still haven't got round to trying this yet, but I think I've got a bit more free time in the new year, so I'm gonna have a go :awe:
Will also have a look at the switchless mod too, but I quite like the fun of soldering switches and wires. My MD already looks like something out of a homebrew Tardis, so a few more wires won't hurt! :lol:
No worries man, I hope you can follow my little write up and photos easy enough. If you have any problems just give me a PM and I'll try to help. Im in the process of making a Jamma-drive 2 myself :D and I'll be overclocking it so I can take better photos etc of the overclock while I do it if you want?

Im also more of a switches man myself too, especially seens I don't have a PIC programmer. I do like the stealthy-ness of the switchless mods though but theres something about wiring up a clicky switch :lol:

Check it out, I wrote up the start of my Jamma-drive here : http://www.porlzilla.com/2012/12/jamma- ... art-1.html Case mod and sticking the Jamma edge to the Megadrive PCB.
NaokiS wrote:Mega Drive to JAMMA? Gotta try that one day myself.
Yeah NaokiS you should give it ago. Its a pretty interesting project I think :)

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Re: Help requested to overclock a PAL Sega Megadrive 2 Conso

Post by joeblade »

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Re: Help requested to overclock a PAL Sega Megadrive 2 Conso

Post by Porl »

Hey Wigsplitta,

I finished off making a Jamma megadrive 2 the other week and thought i'd show ya :) I made 2 videos on it working. Im pretty pleased with how it turned out, it looks a little different to yours :shifty:

I made an expansion port for the jamma edge to hide underneath and to keep the console looking stock when its on the gaming shelf :cool:
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Video 1 showing the insides etc of it.....ignore my geeky voice haha


Video 2 showing it working :)


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Re: Help requested to overclock a PAL Sega Megadrive 2 Conso

Post by o1s1n »

Any of you guys ever have an issue with the overclock and sound chips?

Had a Megadrive 1 modified with an overclock (12mhz I think it was?) and after about a month, the console started sounding strange and metallic.

Eventually the sound went completely.

As a matter of interest, we did a sound chip swap with a working Megadrive and the sound instantly came back.
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Re: Help requested to overclock a PAL Sega Megadrive 2 Conso

Post by NaokiS »

o1s1n wrote:Any of you guys ever have an issue with the overclock and sound chips?

Had a Megadrive 1 modified with an overclock (12mhz I think it was?) and after about a month, the console started sounding strange and metallic.

Eventually the sound went completely.

As a matter of interest, we did a sound chip swap with a working Megadrive and the sound instantly came back.
I would check the voltage you're sending to that chip and make sure it's not slowly frying it.
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Re: Help requested to overclock a PAL Sega Megadrive 2 Conso

Post by wigsplitta »

Only taken me two years to get round to this! Big thanks to Porl for the input and confirming that it all works nicely :thumbup: 8-) :thumbupright:
I understand that it looks a total mess, but I just wanted to confirm all components/connections were working before I finish and make it (marginally) more pretty!
But, importantly, it does work, and it makes some games a whole lot more sweet to play. I'd definitley recommened it for anyone who's tempted. The goods I got all came in batches of at least two, so for anyone interested, I'll be putting a whole kit in (apart from different coloured wires) a sales thread along with a load of other stuff I've been meaning to sell for ages.
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Re: Help requested to overclock a PAL Sega Megadrive 2 Conso

Post by Porl »

Hey Wigsplitta!! :D Thats awesome you got round to overclocking it and it works! :awe: :awe: It's so cool to see another MD2 thats now Mega-Powered up a bit more!! Its a bit scary wiggling that tiny processor leg out isn't it?! haha.

Thanks for the update on your megadrive, its so cool to see another one! :awe:

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