Sega Master System 2 (SMS)

This section covers the pinout for the controller, RGB, composite and S-video modding of the board and tapping off the audio of the Sega Master System 2.

The SMS is a very good console system with some great games on it, and was the predecessor of the MegaDrive / Genesis console.

The SMS played US and UK games on the console without region modding required, although Japanese game carts are a different shape.

Note – don’t get the Model number 3006-05A made in Thailand as it doesn’t contain the Sony CTA chip you need to RGB mod the system – look for the Model number 3006-05 from China, that has the CTA chip. It looks like there were some revisions – the serial number of the Chinese one (you want) of mine was about 110 million, the Thailand one was around serial number 230 million.

The SMS2 says it needs 9v at 500mA, in reality, it will input 7.2v – 12v happily as the voltage feeds straight to a 7805 to feed 5v to the console. (not ideal to use 12v though as the surplus voltage is given off as heat so means more heat in console, so 7.2v – 9v input is more ideal).

Modding video

Related pictures:

Audio and video modding

The audio is tapped off the Sega 315-5246 chip, pin 15

And the video off the Sony CXA1145p chip


We don’t need to use a controller as each wire connection in the controller cable goes directly to the button  on the controller itself.


Cart slot relocation

Here is a pic to show a cart slot relocated using 7.5″ wiring


11 Responses to “Sega Master System 2 (SMS)”

  1. Good work! Nice mod for master system 2 My console has come to life thanks to your information. thank you!

  2. I just tap sound off CXA1145P sound input or output , both perfect. Also just commenting because I just got my first Thailand made SMSII after having about 20 black top Chinese ones and a couple grey top Japanese made ones. Found this page and had to check. It’s the same motherboard as the Chinese versions in my case, same Sony chip to tap RGB/ composite off

  3. I have a tectoy sms 3 with Sonic built in. It’s a
    PAL-M system. It has the MB3514 Encoder and a 315-5681 asic chip. I live in the usa and need to convert it to ntsc, I am unsure how to do this on this version as set up is different that a sms 2, which I have successfully done. Please help. Can supply pics of board.

    I have composite working, audio works, video works but is in Black and White only.


  4. Hi
    I really need some help.I’ve modded 3 consoles with capaciter and a ohm resister.but every time I add the resister the colour goes all funny.I’ve seen you tube vids wear they don’t use either just wires.Is it ok to leave out the ohm resister and just have the capasiter?Will it eventually fry?
    Regards jae.

  5. look nice but how did you have relocated the card slot

  6. why not just add a nice screen and player out port to a game gear? the hardware is the same..

  7. Looks cool.
    What case are you planning to use?

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