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BASIC PROGRAM
The program in Listing 4-1 can be used to produce
a color bar pattern on a Z-100 with the color option.
1. Turn on the computer.
2.
Boot Z-DOS and start Z-BASIC.
3.
Enter and run the BASIC program in Listing 4-1.
Listing 4-1.
BASIC Color Bar Program
10 REM clear screen
20 CLS
30 REM produce color bar
40 LINE{O,0)-{79,106) ,O,BF
50 LINE{80,0)-(159,106) ,1,BF
60 LINE(160,0)-{239,106) ,4,BF
70 LINE(240,0)-(319,106) ,5,BF
80 LINE(320,0)-(399,106) ,2,BF
90 LINE(400,0)-(479,106) ,3,BF
100 LINE{480,0)-{599,106),6,BF
110 LINE(560,0)-(639,106), 7,BF
120 REM label bars
130 LOCATE 13,5
140 PRINT TAB (5); "BLACK"; TAB (15) ; "BLUE"; TAB (25) ; "RED";
150 PRINT TAB (35) ; "MAGENTA";TAB(45); "GREEN";TAB(55); "CYAN";
160 PRINT TAB (65) ; "YELLOW"; TAB (75) ; "WHITE"
170 REM end of program
180 END
Touch Control
Sensitivity Adjustment
Perform this procedure before you attempt fault isola-
tion and also after you repair the touch control system.
Refer to Figures 4-23, 4-24, and 4-25.
1. Display the PLATO TOUCH Grid from the touch
control system.
Page 4-10
2. Set S101 (See Figure 4-23 for location) switch 6
off (away from the board).
3. Connect an oscilloscope to TP1 on the logiC board
and observe the pulses that result from the in-
frared LED strobe. (Set the oscilloscope to 500
J.Ls/Div. and 2V/Div. See Figure 4-5.
4. Turn R204 sensitivity to the counterclockwise stop
(maximum sensitivity). The negative peaks of the
pulses should be "bright", indicating saturation.
5. Turn R204 slowly clockwise to bring the pulses
out of saturation (back off from the negative
peaks).
6. Check the amplitude of the weakest pulse (See
Figure 4-5). If this pulse is less than 1.2 volts peak-
to-peak, adjust R204 until it is 1.2 volts peak-to-
peak.
Figure 4-5
LED Strobe Pulses (TP1)
7. Reset S101 switches for operation, 2 and 3 off
(away from the board) and all other switches on
(toward the board).
Servicing
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