The Retina ZII is Zorro-II graphics card which enables the A2000, A3000, and A4000 to display screens in 8-, 16-, and 24-bit color modes.
RAM
The board can have 1M, 2M or 4M of RAM. With 1MB no 24-bit modes are available; with 2MB onboard you still can't reach resolutions of 1990x1426 or 1024x768-24Bit; these resolutions require an upgrade to 4MB.
For 1MB or 2MB RAM configurations, 414256 chips are used (1Mbit-ZIP-RAM). For upgrading the card to its maximum size of 4MB, 4Mbit-ZIP-RAMs like 414400's must be used in sockets 1,3,5, and 7.
RAM speeds of 80 ns will work, although the manual recommends the use of 70 ns, as not all 80 ns RAMs seem to be fast enough.
The detection of the RAM size is done automatically by the software.
Troubleshooting
If the RAM size is detected wrong, or an alert claims the Retina to be completely without memory, you can remove the jumper JP. This forces the Retina to produce waitstates which might be necessary for the use with some accelerator cards.
Board Layout
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|# Video
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|# (HDD15)
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8 7 6 5 4 3 2 1
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JP |
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Jumpers
JP: Wait States
On: No wait states (Default)
Off: Enable wait states
Video Port Pin-Outs (HDD-15)
Pin 1: Red
Pin 2: Green
Pin 3: Blue
Pin 4: NC
Pin 5: Ground
Pin 6: Ground
Pin 7: Ground
Pin 8: Ground
Pin 9: NC
Pin 10: Ground
Pin 11: NC
Pin 12: NC
Pin 13: Horizontal Sync
Pin 14: Vertical Sync
Pin 15: NC