Master System:Model 1 SMS SMSFM Installation

The SMSFM board was primarily designed for installation in an original model Master System, and is therefore the easiest console to install it in. The general procedure for adding an SMSFM is largely the same on all model 1 revisions, with only the solder points for the audio wires differing.

This guide also applies to the Brazilian Master System/Master System II.

Materials and Tools

Materials

• SMSFM board
• Leaded solder
• Flux (not required but recommended)
• Hookup wire (optional depending on install)

Tools

• JIS/Phillips head screwdriver
• Soldering iron
• Desoldering braid or desoldering gun
• Flush cutters (optional)
• Wire stripper (optional)
• Drill with step bits (optional)

Procedure

1. Flip over the Master System and remove the six JIS screws securing the case. Remove the top shell and set it aside.
2. Most Master Systems will have RF shielding covering the motherboard, remove it and undo the remaining screws securing the motherboard. Set the bottom shell aside.
3. Remove the heat sink for the 7805 voltage regulator. This may pose some difficulty on early board revisions as the 7805 is mounted inwards and is screwed into a very large heat sink.
4. Begin assembling the SMSFM by soldering in the 50-pin connector. The components on the SMSFM need to be facing towards the front of the SMS, and needs to be soldered in at an angle so that the top of the SMSFM is tilted towards the front. If you do not tilt the SMSFM, it will not fit inside the top case.
   • See Figure 1.
5. Solder the pin header for the FM enable/disable/region switch onto the SMSFM, with the pins facing out so it is easier to connect the switch.
6. Solder the supplied wire harness to the switch.
7. With the SMSFM board assembled, connect it to the expansion port at the rear of the SMS motherboard. Note that if you are keeping the top RF shield, you will need to either bend or cut the prongs that protrude from the shielding towards the expansion port, otherwise the SMSFM will not fit.
   • See Figure 2.
   • Be extremely careful cutting the RF shield as it will be very sharp. If desired, the cut edge can be dulled using sandpaper or a rotary tool.
8. For the final installation step, the audio cable from the SMSFM needs to be soldered into the SMS motherboard. The white wire carries the standard PSG audio, where it will be mixed into the SMSFM. The final output including FM audio then goes out from the red wire. In addition, the cable on the SMSFM has an extra shield ground to reduce interference, which needs to be soldered to a ground source on the SMS. Soldering these wires will vary depending on the motherboard revision; follow the subsections below according to your specific console.
9. For the switch, it can be placed inside the expansion port cover with the wire harness bunched up for a no-cut mod. If you want the switch to be easily accessible, a hole can be drilled on the rear of the top case or the RF modulator can be desoldered, which will leave a decent size hole for the switch without drilling into the case. Note that you may need to fit a washer behind the switch if you decide to fit the switch in the RF output hole.
10. Place the motherboard back into the bottom shell and test. If you did not reattach the heat sink for the 7805, only test long enough to verify that the mod is working as the 7805 will overheat very quickly and shut down without a heat sink.

Procedure for Audio Points

837-6067

This is the original board revision for the NTSC SMS. It is denoted by the use of metal leaf switches for Pause and Reset and a massive heat sink for the voltage regulator.

1. Desolder or cut out capacitor C49, which is located below the RF modulator.
2. Connect the white wire to the positive lead for C49 and the red wire to the negative. The ground wire can be soldered to the RF modulator casing or a nearby ground plane.

837-6097

This is the original board revision for the PAL SMS and also uses metal leaf switches.

1. Desolder or cut out capacitor C48, which is located below the RF modulator.
2. Connect the white wire to the positive lead for C49 and the red wire to the negative. The ground wire can be soldered to the RF modulator casing or a nearby ground plane.