[Apr/04/2004]

Rough Racer
Sega, (1987?)

This is a kit upgrade for Sega System 24 hardware.
The kit consists of...
- Maxell Super RD MF2-256HD High Density floppy disk with label 'DS3-5000-06B'
- Hitachi FD1094 CPU with label 'SEGA 317-0058-06B'
- Custom I/O Controller PCB labelled '834-6510-01'

I/O Controller PCB Layout
-------------------------

834-6510
(sticker 834-6510-01)
                        ___________
|----------------------|  IDC 34   |---|
|                                      |
|                                      |
|  D4701          %2                   |
|                                      |
|                 %3                   |
|    %1                       74LS139  |
|                CN1                   |
|     --------------------------|      |
|     |--------------------------      |
|--------------------------------------|


Notes:
      - The main PCB uses the standard System 24 EPROMs EPR-12186 and EPR-12187
        and a regular 68000-10 in position IC3. The Hitachi CPU sits at 
        position IC4.

      - Dip Switch 1 is used for coinage.
        Dip Switch 2 is used for the following (with all dips off by default)
        1:   1 credit to start, 1 credit to continue
        2:   Attract sound     OFF
        3:   Monitor flip      NORMAL
        4:   Game Instructions YES
        5,6: Difficulty        NORMAL
        7:   Start money       $15000
        8:   Number of Nitros  10
                        
      - %1 - Unpopulated position for D4701 IC
        %2 - Unpopulated position for MSM6253RS IC
        %3 - Unpopulated position for MSM6253RS IC
      
      - CN1 is shown for completeness, it's actually underneath the I/O PCB.
      
      - The custom I/O board plugs into the top connector on the main board and
        is used for player steering controls. The wiring diagram has 8 pins coming from
        the connector. Four are labelled 'JST4P 1P (L)', the other four are labelled
        'JST4P 2P (R)'. I assume this is for an analog wheel or similar for player 1 
        (being on the left) and player 2 (being on the right)
        The wiring diagram also lists some buttons for both PL1 and PL2 coming from
        the regular 56-way edge connector....  'Nitro' and 'Accel'
        The manual shows a controller that looks like a spinner which they call
        a 'sensor board' with part 839-0138 and has a photo-sensor disc, which looks
        like it's used for steering.
        The manual also mentions Hot Rod and shows a cocktail cab, so maybe this 
        kit is an upgrade for Hot Rod cabinets.
        
      - There might be a pattern of naming on the floppy disks. Sega uses the 
        same DS3-5000-xxx naming conventions for all the ones I've seen so far.
        The xxx is the last part of the Hitachi CPU number, it seems.....
        So if one had the Hitachi part number and a floppy without a label, it's
        possible to create the correct floppy disk name :-)

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