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Sega Master System 2 FM Sound Module Adapter

New mod released for the Sega Master System model 2. The FM Sound Module Adapter.

What is the Sega Master System 2 FM Sound Module Adapter?

The Japanese Sega Master System is capable of playing back both the PSG (Programmable Sound Generator) and FM (Frequency Modulation) audio that is programmed into some games because the consoles contains both the SN76489 PSG chip and the YM2413 FM chip. US and European consoles only contain the PSG chip which means they can not play back the FM audio.

This was fixed when Tim Worthington created the FM sound module which is a device that plugs into the external port of a Sega Master System model 1 to allow the FM sound contained in some game cartridges to finally be played on US and European consoles.

More info about Tim Worthington’s Sega Master System FM Sound Module can be found here https://etim.net.au/shop/shop.php?crn=202&rn=538&action=show_detail

The SEGA Master System model 2 however, does not have an external port in which to plug the FM sound module so there is no easy way of getting FM sound to play on this model.

That is until now.

Sega Master System FM Sound Module Adapter straight on white background.
Five Sega Master System 2 FM Sound Module Adapters fanned out on white background.

This adapter adds a faux external port back to the SMS2 so the FM Sound Module can be plugged in. It makes all the same connections from the cartridge port to the FM Sound Module as would be made on a model 1 Master System.

FM Sound Module Adapter Design

The prototype worked first time so there was no adjustments needed which means from designing the PCB, installing and testing the prototype, to putting in the main order was a relatively quick turnaround compared to a lot of designs. I wish they all went this smoothly. The PCBs have castellated vias and HASL finish to match the aesthetics of the Master System motherboard and external port of the model 1.

Like all my designs I ignore the superfluous and try create something simple and optimised for the task. I also want the designs to look good once installed and this is no different. The PCB is some of my finest trace work and the fitment is perfect and fully compliments the Master System 2.

Bottom side of Sega Master System 2 FM Sound Module Adapter install.
Top side of Sega Master System 2 FM Sound Module Adapter installed with attached FM Module.
Top side of Sega Master System 2 FM Sound Module Adapter installed with attached FM Module. Shown in Master System bottom case.
Top side of Sega Master System 2 FM Sound Module Adapter installed with attached FM Module. Shown in Master System bottom case with RF shield on.

Installing the FM Sound Module Adapter

The audio will need wiring from the FM module in exactly the same way as a standard Master System 1 install. First removing the audio capacitor from the SMS board and then soldering the Red, White and Ground wires. The FM sound can be switched on and off by using a switch and drilling the case, or by connecting up the wires to any of the Consoles Unleashed Sega Master System switchless region mods and controlling the FM sound module switchlessly via the pause button on the console or the pause button on the controller if using a Consoles Unleashed pause mod. This is definitely the best way to get the most from the FM sound module.

Master System 2 switchless region mod installed showing FM Sound Module connections.
Top side of full Master System 2 PCB showing lots of installed mods. Switchless region, RGB video, and FM Sound Module with FM Sound Module Adapter.

There is nothing more to it. Very easy to install. The hard work has been done, now go and enjoy some FM sound on your Sega Master System model 2.

Where to Buy the FM Sound Module Adapter?

The Sega Master System 2 FM Sound Module Adapter is available to buy from the following link. https://www.consolesunleashed.com/product/sega-master-system-model-2-fm-sound-module-adapter/

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