Sega Master System FM Modification




Introduction: Sega Master System FM Modification

Hi all,

In this instructable set, I will detail the stages of installing the FM sound board onto your Sega Master System pcb.

The things you will need for the job:

  1. FM sound board kit - I got mine from the source itself, Tim Worthington at
  2. Wire splicer
  3. Soldering iron
  4. Solder (solder flux is also recommended)
  5. Solder pump
  6. Dremel or any type of tool for metal cutting and hole drilling

The job will require basic soldering skill. be sure you know how to hold a soldering iron and use it.

Step 1: The Kit Preparation

The new kit is more DIY than the old one in terms of you will need to solder the black pin connector to the PCB by yourself (the idea is to use smaller envelopes and save some money on shipping).

The kit consists of the PCB itself, a black pin connector (female), a toggle switch and a switch wire harness.

First of all, prepare your kit for the implementation:

Place the black female connector alligned with the holes on your PCB. Solder the tips of the female connector to the PCB (the usage of solder flux is recommended).

Step 2: Prepare the Connection Wire

Splice the wire and reviel the red, white and GND leads.

Step 3: Opening You Master System

Basically open all the screws to enable the Master System PCB removal from the case.

Step 4: Locate C49 Capacitor

Locate the C49 capacitor on your board. I got to see it after I've removed the metal heat sink that was attached to the voltage regulator.

Please note that the C49 is the component to be replaced on my NTSC Master System. If you got other version of Sega Master System, reffer to

Step 5: Remove C49 Capacitor

I've used a solder sucktion pump to clear all the solder from it's legs and removed it.

Step 6: Placing the Wire Leads

Place the white and red as described in the pic. the GND will be soldered to the metal case of the RF module.

Step 7: Fitting the Metal Shield to the FM PCB

Since the FM PCB sticks out, a modification for the metal sheild needs to be done.

I've used the Dremel multi tool for the job.

Step 8: Make a Hole for the Switch

The hole should be drilled on the right area of the upper case.

Step 9: Put Everything Back in It's Place and Play Some FM Games :)

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    1 year ago

    I did everything that this instructable said, but my master system doesn't play the fm audio. I think the reason is that the fm board might be double sided, and I only soldered the back side, and I am using a switch with 6 terminals, but I soldered the wires on one side. What do think the reason could be? What can I do to make it work?

    Edit: It was just poor connections. I redid it and now it works fine!

    Folda Fett
    Folda Fett

    4 years ago

    I have a Sega Master System console myself. Your project looks very good, I'm just not very clear as to what you can do once you've modified it. Obviously you must be able to play some type of electronic games. I'm sorry, I just don't know what FM stands for.


    4 years ago

    Neat, have fun playing :)