MV1A

Description

A strangely designed MVS board which uses some chips found in the NeoGeo CD. Maybe allowed SNK to cut costs by using chips for both systems.

Specification
Year	Circa 1995
Number of slots	1
System ROM	Socketed
Cart orientation	horizontal
Memory Card support	no
Joystick support	no
Stereo output	no
Headphone output	no

PALs

See MV1A PALs.

Scans

Main Board

Main Board Front

NEO-BUF list:

• GA4: 68k bidirectional palette access
• GA7: Read P1 and P2 inputs
• GA8: Only half used, read REG_STATUS_B
• GA9: 68k/Z80 communication
• GA11: 68k data bus bidirectional buffer

Others:

• U10: 68k to Z80 latch, clear = SDZ80CLR (NEO-D0 44), clock = SDW (SNK1A 22, NEO-D0 33)
• U11: Z80 to 68k latch, no clear, clock = SDZ80W (NEO-D0 43)
• U3:
  • 3(RAM4 22) = SNK1B-4 OR MGA-51
  • 6(RAM3 22) = SNK1B-4 OR MGA-53
  • 8(U4 1) = SNK1B-4 OR MGA-52
  • 11(U4 4) = SNK1B-4 OR MGA-54
• U2:
  • 3(Cart) = ROMOEL OR MGA-51
  • 6(Cart) = ROMOEL OR MGA-53
  • 8(Cart) = ROMOEL OR MGA-52
  • 11(Cart) = ROMOEL OR MGA-54
• U3:
  • 3(Cart) = ROMOEU OR MGA-51
  • 6(Cart) = ROMOEU OR MGA-53
  • 8(Cart) = ROMOEU OR MGA-55
  • 11(Cart) = ROMOEU OR MGA-72

Main Board Back

Slot Board

Slot Board Front

Slot Board Front