17 Nov
2007
17 Nov
'07
7:28 p.m.
--- Chuck Guzis <cclist at sydex.com> wrote:
On 17 Nov 2007 at 10:22, Gordon JC Pearce wrote:
what would be nice if there was an area for the group
to act as a *scratch pad*. So some of this stuff could
go down *on paper*. Thoughts?...
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>From memory, and it was a while ago, we had
three
voltage dividers to
knock the TTL outputs down to .7v, and then three
more resistors from
the intensity bit to the analogue outputs.
There may have been some diodes there.
The sync combiner was a couple of resistors and a
transistor.
It can also be done with a 74LS06 OC inverter and a
few resistors. A
fancy version might use a '221 one shot to adjust
sync pulse position
and width. I think the one I used to drive an RGB
monitor with SOG
from a VGA output used a 74HC86 XOR and was
self-powered.