Genius 2793 User Manual
Trouble Shooting Handbook
The information that is written in this handbook is to help repair XX93 Monitors.
Color problems.
No video with power.
No V-H sync.
No power.
1.
2.
3.
4.
Color Problems.
Here is a guideline in which this handbook will follow:
When there is a missing color and the lines are white the problem lies in the video
interface section. This means it can be found between the customers game and pin 8 of
the Video Amplifier (K-Film). If the lines are not white it would be a output problem,
which is anything after pin 8 to the picture tube.
interface section. This means it can be found between the customers game and pin 8 of
the Video Amplifier (K-Film). If the lines are not white it would be a output problem,
which is anything after pin 8 to the picture tube.
A helpful hint when working with color problems is by identifying the
color of the three grid lines at the top of the screen.
color of the three grid lines at the top of the screen.
If the problem is excessive blue, green, or red background color,
tap on related K-film to see if it is defective.
tap on related K-film to see if it is defective.
If blue is the problem, check for damaged traces around the outside of
the video board, since most of these traces go to the blue K-film.
the video board, since most of these traces go to the blue K-film.
If monitor shuts down due to excessive color, disconnect the filament for
voltage tests. (Desolder CRT socket pin 9.)
voltage tests. (Desolder CRT socket pin 9.)
Problem
Tests
Probable Solution
Missing
Color.
If voltage, K-Film pin 1 over 10.6V
Desolder pin 1.
Desolder pin 1.
Make open to trace.
If pin 1 over 10.6V, replace K-Film.
If pin 1 is 10V, replace the diode of
If pin 1 is 10V, replace the diode of
Then try replacing the K-Film.
If not solution, change the
transistors in the amplifier.
If not solution, change the
transistors in the amplifier.
If voltage, K-Film pin 20 is
Resistance between these two
points should not exceed 1.1K
points should not exceed 1.1K
Ω
.
If voltage, K-Film pin 20, different
than voltage at CRT socket pin.
than voltage at CRT socket pin.
If voltage, IC
241
pins 16, 13, or 9
less than 7V & K-Films pin 1>8V.
Check for open between IC and
associated K-Film.
associated K-Film.
If voltage, K-Film pin 1 is 10V and
IC 241 Pins 1,15, & 8 are .3 to.7V.
IC 241 Pins 1,15, & 8 are .3 to.7V.
Refer to the
schematic for
the specific pin
numbers of
each color.
schematic for
the specific pin
numbers of
each color.
Ohm gain resistors at pins, if OK
replace video interface IC
replace video interface IC
241
.
Check voltage on 75
Ω
input
resistors
If 0V to .05V, check video
connector and drive electronics.
connector and drive electronics.
First replace, for shorted arc
suppression, diodes of affected color.
suppression, diodes of affected color.
over 115V.
If still missing color, replace IC
241
.
missing color
213
086
084
,
, &
.
241
241
288
286
284
,
, &
.
241
Arc
suppression
diodes:
Red
Green
Blue
Green
Blue
835
899
845
849
886
959
1.
2.
3.
4.
5.
6.
Tests should
preformed in order
to reduce chance of
replacing wrong
component.
preformed in order
to reduce chance of
replacing wrong
component.
Caution; Use only one hand
when working on a powered up
monitor to avoid electrical
shock.
when working on a powered up
monitor to avoid electrical
shock.
Always wear safety glasses.
Retrace lines.
5.
Note: All voltage measurements are: DC with -lead to GND unless other wise noted.
Pins, listed in
table, are in
order of Red,
Green,
and Blue.
Color may be tested by connecting a clip
lead to GND and a 1.62K
lead to GND and a 1.62K
Ω
resistor.
Contact the resistor to K-Film pin 1.
95