Cromemco Dazzler troubleshooting...
Roy J. Tellason
rtellason at verizon.net
Fri Sep 7 22:26:24 CDT 2007
On Friday 07 September 2007 18:50, Bill Sudbrink wrote:
> I have a Dazzler board set that _almost_ works.
> Gray scale looks good and color looks OK, except
> that it's gray too. The shades of gray change
> when I flip the color bit at I/O address 0x0F and
> the red and green pots and the blue variable cap
> change the display when in color mode. The monitor
> I'm using is tested good with a color CCTV camera
> I have lying around. The geometry changes as
> expected with bit changes at 0x0F and the "dots"
> change as expected when the memory at the address
> assigned at 0x0E is modified. My guess is that
> something is wrong in the color burst (is that the
> right name?) circuit? Or is it possible that there
> is something different about the signal that a newer
> (manufactured Jan. 1993) color monitor wouldn't like?
> Unfortunately, the scan of the Dazzler manual on the
> Harte Technologies web site is not at a high enough
> resolution for the schematics to be read in detail.
> A better scan of the schematics would be greatly
> appreciated as would any other help, video signal
> generation is not my strong suit.
Got a scope? That's the best way to look at the output signal, and work your
way back into it until you find out why there's no colorburst in there...
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, a critter that can
be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
Information is more dangerous than cannon to a society ruled by lies. --James
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