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av:sega_mark_iii_rgb_amp [2005/12/25 23:13] – Added BackupTechnique link, extra info nfgav:sega_mark_iii_rgb_amp [2014/02/01 09:31] – Alternate amp added ApolloBoy
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-===== Sega Mk III RGB Amp ===== +===== Sega Mark III RGB Amp ===== 
-The Sega Mk3 console has RGB output, but it's very weak.  This amplifier will cure the problem.  +The Sega Mark III console has RGB output, but it's very weak.  This amplifier will cure the problem.  
  
-It may work for the SG-1000 as well, but there seem to be other problems with the SG1k output that this amp does not address.+It may also work with later revisions of the SG-1000 II which use an RGB-capable VDP, but this has not been tested.
  
 ==== The Circuit ==== ==== The Circuit ====
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   * This circuit will need to be repeated for every signal - Red, Green, Blue and Sync.   * This circuit will need to be repeated for every signal - Red, Green, Blue and Sync.
   * The variable resistor at the end is optional.   * The variable resistor at the end is optional.
 +
 +====Alternate Circuit====
 +You can also substitute the above amp with one based around the THS7314 chip. The amp design is based on the one [[http://www.mmmonkey.co.uk/ntsc-nintendo-64-rgb/ |found here, which was originally designed for the N64]]. The RGB outputs are tapped directly from the VDP (these outputs are also marked on the motherboard), while 5V and ground can be pulled from the 7805 regulator. The resulting image will be very bright, so you may want to replace the 75 ohm resistors with ones of a higher value. For sync, you can use composite video, or you can substitute the THS7314 with a THS7374 to amplify the composite sync output in addition to the RGB signals.
 +
 +As with the amplifier design above, this circuit may also work with the later version of the SG-1000 II.
  
 ----- -----
-Many thanks to [[Backup Technique and Game Lab|Backup Technique]] (バックアップ括用テクニック) magazine (Volumes 8 + 9), from whence this diagram came.+Many thanks to [[nfg:backup_technique_and_game_lab|Backup Technique]] (バックアップ括用テクニック) magazine (Volumes 8 + 9), from whence this diagram came.
  
 Thanks also to [[http://tripoint.org/kevtris/|Kevin Horton]], for helping fix the diagram, which was incorrect. Thanks also to [[http://tripoint.org/kevtris/|Kevin Horton]], for helping fix the diagram, which was incorrect.
av/sega_mark_iii_rgb_amp.txt · Last modified: 2019/08/27 20:45 by 127.0.0.1