My latest problem with the Apple II+ I am trying to restore is that the graphics is always monochrome, and no colors are displayed.
I do the following to test low-res graphics:
<br /> CALL -151<br /> C056<br /> C054<br /> C050<br />
which turns on low-res graphics, which displays the contents of the text memory, so I get a grid of gray blocks (a few are darker or brighter), but no colored blocks. I have tried it on my Apple IIe, and it behaves the same way except that a few blocks now do have color. I did check video output on an oscilloscope, and it seemed like there is a color signal present (e.g. I saw the 3.58 MHz color burst). Why isn't the II+ displaying any colors? Any ideas what could be wrong?
While speaking of the video; I discovered that there was a tremendous improvement of the video on my small TFT-monitor I bought recently when I reverted the 50 Hz modification on my II+. With the 50 Hz mod, I could barely read some characters, but without the mod, everything is crystal clear.