Re: Lisa Video Out Trouble

According to the Lisa Hardware Reference Manual 1983, page 3-23:

The composite video interface conforms to RS170 voltage levels, the horizontal frequency is 22,400 Hz and the vertical frequency is 60 Hz.

Since there are 364 rows of pixels, plus another 15 retrace lines (usually invisible unless you turn the brightness way up), the horizontal sweep is (364 + 15) * 60 = 22.74 KHz.

The dot rate bandwidth is 20.375 MHz (the frequency of the crystal on the CPU board).

If you have the 3A ROMs (square pixel screen modification kit), then there are 432 rows of pixels, and the horizontal sweep is then around 27 KHz.

I believe that monitors for the Apple II are designed for a bandwidth of 14 MHz and horizontal sweep of 12 KHz (to support 192 rows), so the Lisa video requires a monitor with substantially better performance.

>What is the Lisa's video signal timing?

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