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IIsi and AppleColor problem

I have bought a 2nd hand IIsi with 5MB RAM and the AppleColor 14" display. It runs system 7 and it looks OK for 16 colors. When I switch to 256 colors, all the colors change (it definitely doesn't look right). The memory allowance for the screen is for 256 colors. I don't think there is a memory problem. Am I lacking an extension for the monitor? Any suggestions would be valuable.

1 Solution
You shouldn't need an extension with a iisi and a apple color 14' Has somebody messed about with the gamma settings (hold down the option (alt) key and select option in the monitor cp)

I think the IIsi (alng with the IIci) uses the standard Ram as video ram. Rather than seperate video ram as in later machines.

If you have a 5 M machine that is 1M soldered and 4x1MB expansion, isn't it?

After the system software has grabbed what it wants there may not be enough for display ram. I have seen problems with dicky VRAM on LC series machines that was cleared up but replacing one of the VRAM chips but this wont help you.

Here is a excerpt from a Tech Note

The 24-bit memory map on the Macintosh IIsi is the same as for all other Mac II systems. It allocates 8 MB for RAM, 1 MB for ROM, 1 MB for I/O and 6 MB for expansion slots. However, because of the slot table, the on-board video takes up 2 slots rather than 1, which results in 2 MB allocated for on-board video. That means there is 16MB -1MB (I/O) - 1MB (ROM) - 2MB (on-board video) =12 MB maximum RAM available.

I would recommend a Low Level format and a custom MacOS install for any Macontosh. That will give you the extension called:
IIci/IIsi Monitors Extension
and assemble the files System and Finder correctly.

-good luck
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