Master System:SMS II SMSFM Installation

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Installing an SMSFM board in a Master System II can be more challenging and tedious than a model 1 since it does not have an expansion port. A fair amount of manual wiring is needed, but the process can be made easier with the use of an adapter board, such as the one sold by Consoles Unleashed.

These instructions apply to all Master System II consoles as well as the Korean Samsung Gam-Boy II and Aladdin Boy.

Materials and Tools

Materials

Tools

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

Assembly and Installation Procedure

  1. Flip over the Master System II and remove the five screws securing the shell. When all five screws have been removed, tilt the top shell towards the front to remove it. This is because there are two small tabs which hold the top shell in place alongside the screws.
  2. Unscrew the top RF shield and set it aside. Carefully remove the main board along with the bottom RF shield, then set the bottom shell and shielding aside.
  3. Solder the pin header for the FM enable/disable/region switch onto the SMSFM, then solder the supplied wire harness to the switch.
  4. The SMSFM will need to be wired manually to the SMS II's motherboard, consisting of about 20 wires. Follow the SMSFM wiring diagram and the Master System II schematic to determine how to wire up the SMSFM. Many of the signals are part of the main system bus and can be found in multiple places.
    • If you have the Consoles Unleashed adapter board, place it over the cartridge port pins on the underside of the motherboard. Solder the adapter board in so the edge connector is outside of the board, and with the odd-numbered pins facing up. Solder the included 50-pin connector onto the SMSFM board and connect it to the adapter board, with the top facing up.
    • Note that if you have a Korean console, you cannot use the Consoles Unleashed board as it was intended for consoles with a 50-pin cartridge port. You will need to wire the SMSFM manually on these consoles.
  5. Next, the audio cable from the SMSFM needs to be soldered into the SMS motherboard. Cut the audio cable to the appropriate length for your particular console, then strip the cable. Twist the copper ground braid into a wire and tin it. Strip back the individual red and white wires inside the cable and tin them.
  6. 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.
  7. For the final installation step, a small hole needs to be drilled in the bottom case for the FM enable/region switch. Drill a pilot hole using a small bit, then use a step bit to enlarge the hole to the correct size for the switch. Mount the switch.
  8. Place the motherboard back into the bottom shell and test. If the SMSFM is working as intended, reassemble the rest of the console. If not, double check your wiring.

Procedure for Audio Points

VA1

This is the only board revision for the NTSC and French SMS II.

  1. Desolder or cut out capacitor C62, which is located below the CXA1145 video encoder.
    • For French consoles, desolder or cut out ferrite bead FB55.
  2. Connect the white wire to the negative lead for C62 and the red wire to the positive. The ground wire can be soldered to the RF modulator casing or a nearby ground plane.
    • For French consoles, connect the white wire to the right-side via for FB55 and the red wire to the left-side via.

M4Jr. PAL

  1. Desolder or cut out capacitor C31, which is located below the CXA1145 video encoder.
  2. Connect the white wire to the negative lead for C31 and the red wire to the positive. The ground wire can be soldered to the RF modulator casing or a nearby ground plane.

M4Jr. PAL 2M

  1. Desolder or cut out capacitor C31, which is located near the lower right corner of the MB3514 video encoder.
  2. Connect the white wire to the negative lead for C31 and the red wire to the positive. The ground wire can be soldered to the RF modulator casing or a nearby ground plane.

M4Jr Korea

  1. Desolder or cut out capacitor CE11, which is located below the CXA1145 video encoder.
  2. Connect the white wire to the negative lead for CE11 and the red wire to the positive. The ground wire can be soldered to the RF modulator casing or a nearby ground plane.
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