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COVID-19 UPDATE: Shipping is affected by the UK lockdown starting 23rd March 2020. I am still shipping worldwide but will no longer go to the post office. All mod kits will be posted as standard large letter. Install service returns are posted via tracked & signed courier. Many thanks

Sega Master System Model 2 RGB Video Mod Install Guide

WORK IN PROGRESS. THERE WILL BE ERRORS.

This guide will show you how to get RGB video out of the Sega Master System model 2 using only passive components. It will focus mainly on matching the Master System 2 to the original Master System components. It will be backwards compatible with all stock Master System or Mega Drive 2 cables.

Mod Pinouts

The mod is concerned with two ICs inside the Master System. The Video Display Processor and the RGB Encoder.

Sony CXA1145P RGB Encoder

  • Pin 23 for Red Video
  • Pin 22 for Green Video
  • Pin 21 for Blue Video
  • Pin 20 for Composite Video
  • Pin 10 for Composite Sync (Yes, from the C-SYNC IN pin)
  • Pin 9 for Mono Audio signal

SEGA 315-5246 Video Display Processor

Components

A look at other guides and the differing components used, from the most components to the most minimalist that this guide will aim for.

Hardware Comparison

A comparison of the video and audio elements in the schematics and hardware of the Master System and Master System 2.

Master System early revision

Signal IC Pin Component Component Component Component Component AV Connector Pin
Blue Video Sony V7040 21           8
Green Video Sony V7040 22           5
Red Video Sony V7040 23           6
Composite Video Sony V7040 19 R27 (75ohm Resistor) C28 (+/-) (100uf/10v)       3
C-Sync In Sony V7040 11 (2.2Kohm to +5V)         7
Mono Audio SEGA 315-5124 10 CX1 (to Ground) R46 (2.2Kohm to Ground) Q48(B) (C to +5V / E to next) R47 (10Kohm to Ground) C49 (+/-) (10uf/25v) 1

Master System VA3 (In Progress)

Signal IC Pin Component Component Component AV Connector Pin
Blue Video SONY CXA1145P 21       8
Green Video SONY CXA1145P 22       5
Red Video SONY CXA1145P 23       6
Composite Video SONY CXA1145P 20 R61 R64 (+/-) (100uf) FB7 3
C-Sync SONY CXA1145P         7
Mono Audio SONY CXA1145P 9 C71 (+/-) (10uf/16v) FB8   1

Master System 2 (In Progress)

Signal IC Pin Component Component
Blue Video SEGA 315-5246 29    
Green Video SEGA 315-5246 28    
Red Video SEGA 315-5246 27    
Composite Video SEGA 315-5246      
C-Sync SEGA 315-5246      
Mono Audio SEGA 315-5246 9    

Output Audio/Video Connector

There is a choice of two connectors to make it backwards compatile with Master System of Mega Drive 2 cables.

9-Pin Mini DIN (Through hole/Surface mount)

262 Degree "U-shape" 8-Pin DIN (Panel Mount version)

Solder Map

Removing the RF Output

Coming soon.

Mounting the New AV Output Connector

Coming soon.

Notes to be included in main body of guide.

  • CXA Pin 10 'C-Sync In' is connected to +5V with a 2.2k Ohm resistor so this is not needed on a perfboard if this pin is used.
  • C-Sync will be TTL so components are necessary in the SCART cable to bring this down to a usable level for the TV. (Matches Master System and Mega Drive 1 & 2)
  • RGB are all direct out from CXA to AV connector. No components needed as they should be inside the SCART cable.
  • Components needed on the CVBS line to match Master System 1.