June 1997
STAR*TECH JOURNAL
Enzo's
Tech
Tips
"Hey Enzo, I can't find the self-test button on this Captain Fantastic!,,
Douglas 'Enzo' Mccallum • Shiawassee Technical Services • Lansing, Ml
SE 1 11NG UP A Co1N-OP SERVICE BENCH (PART
7)
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Unless you haul all your service needs to someone else< you must have a shop for
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maintenance and repair of equipment. Depending upon your needs~ the size of yow;
and the thickness of your wallet your shop could be anything from the garage to the
house on up to a huge professional faclllty. Whatever league you ore in, the work bench Is
: an important part of the shop. Here are some considerations for setting up a service bench.
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EQUIPPING THE BENCH -VIDEO PATTERN GENERATOR
MAJORITY
SELECTION
SHOP
A lot of the work that comes
across my bench is monitors. To
work on monitors you need cer-
tain basics.
If you buy a commercial general
purpose unit, it should have RG B
outputs and the ability to turn off
the individual colors so you can
work on one gun at a time. RG B
simply means separate Red,
Green, and Blue signals.
Most commercial units provide
composite video. A lot of them
do not provide RG B outputs, so
shop carefully.
• You need the space to do it in.
• You need a source of power.
• Remember monitors MUST
have isolated AC supplies. I
naturally recommend the isola-
tion transformer and Variac com-
bination I have described earlier
in this series.
• You also need a video pattern
generator. A pattern generator
is a source of video signals, which
are applied to the monitor inputs
so it can produce useful images
on its screen.
The sync signals are also sepa-
rate. Composite video is one sig-
nal that combines all the color
and sync information onto one
line. This is the sort of signal that
comes out the "video" jack on the
back of your VCR.
RF outputs are composite video
modulated onto a standard TV
channel for application to a tuner
through its antenna connections.
There are applications for com-
posite video, such as old mono-
chrome monitors, converted big
screen TVs and the like.
PATIERNS
Pattern generators produce a va-
riety of screen images. I use the
cross hatch pattern almost exclu-
sively, but the color bars and
other patterns have their use.
CROSSHATCH
The straight lines and resulting
rectangles of the cross hatch fa-
cilitate convergence alignment