gene@uicsl.UUCP (12/09/86)
I experienced two successful C-128 (80-column), to Monochrome Composite-video
with simple, direct connections: In both cases, the 80-column display was
excellent. One case was to the monitor-portion of an old Infoton Vistar/II
computer-terminal( Just the separate monitor portion, model DM-126)....and
the other case was a new 12" green-screen (no sound) Model MN-012G1 that I
just bought for $79.95 from "Montgomery-Grant"....I also bought their C-128
for $249.95. They have ads in RUN & COMPUTE's Gazette. Call collect at
(212)594-7140, although the number that I dealt with was collect (212)
732-4500. The Model MN-012G1 comes with a suitable cable for 40-column
(or C-64) which is also where the sound comes out on the C-128.
To add 80-column, simply use 2 or 3 ft. of twisted wire. or coaxial
if you prefer...I simply stripped two adjacent strands off some ribbon-
cable. One is ground, between pin 1 of the C-128 9-pin"D" to ground
(outside shell of the RCA-type phono connector), and the other one is
the C-128 monochrome (pin 7 of 9-pin"D") which will go to the center pin
of the RCA-phono-type plug of the monitor. ACTUALLY, of course, you will
probably prefer to improvise a single-pole, double-throw switch, with
the monitor-video-input on the common terminal, and 80-column / 40-column
on the other two. If you have audio in your monitor, or add it in
later, it stays connected full-time to pin 3 of the 40-column 9-pin DIN.
(ground is pin 2, and 40-col video is pin 4).
I would recommend not accidentall shorting the video-out wires from
the C-128 because my checks indicated that it is about a 10-ohm generator
and shorting could cause substantial currents to flow.
Also, be warned that one cannot expect that all composite-video
monitors will experience the same good-luck that mine have....probably
some tinkering with amplitude, and or DC-restorers, will make them
acceptable, though.
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Gene Gardner {ihnp4,pur-ee}!uiucdcs!uicsl!genegene@uicsl.UUCP (12/09/86)
A further comment: if anyone happens to get a model MN-012G1 under their
Xmas-tree, there is a width-coil (accessible by removing back cover) that
will widen the display nicely....simply screw the ferrite-slug almost all
the way out (using hex-tool, or allen wrench). Commodore is a little stingy
on the width of their image. Coil is labelled L-404. My unit has a near-
perfect display, with the small dots resolved & focused over the entire
surface area of the display.
One other comment....the Vistar/II mentioned above, was actually an
Infoton Vistar/GT....altho both might have similar composite monitors.
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Gene Gardner {ihnp4,pur-ee}!uiucdcs!uicsl!gene