Date : 10/02/98 R7621127
Sync+Vertical Deflection
R7621127
19
Technical description
This is realised by triggering the second one - shot by the trailing edge of the former
"overshoot" pulse. The width of this pulse is also a lot smaller compared to the former
one.
2. Generation of the blanking and unblanking pulses
As mentioned earlier the opposite polarity output pin 4 (
BL PULSE INV
) of the
double one-shot IC414 is used for blanking (see sheet 2) during the vertical retrace
time.
To unblank the video during the ABL time (see composite blanking), the
"ABL
PULSE INV"
from pin 12 of the double one-shot is used.
3. Pulses for the controller and the RGB DRIVER (ABL measurement)
V pulse (for the controller)
The two outputs at the pins 13 and 5 are added with D420 and D414 and then buffered
with Q417. The
V PULSE
is protected by the diodes hooked to the +5V and ground
with D419/D418 and sent to the microprocessor-controller board via the main board.
ABL pulse (for the RGB DRIVER):
The shorter pulse and delayed with respect to the overshoot generated by the
second one-shot is buffered with Q411 before leaving this module. It is used on the
RGB DRIVER board to determine the time for the 'black current' measurement.
2. Vertical output stages, vertical shift and
amplitude control
The
VERT SWT
at the node R410 / R409 is sent to the BELLA IC406 (VRP
0
, pin
17) for adjustment. The output VO
0
(% VERT SWT) is then passed through the 'ABL
overshoot as described above.
It is now capacitively coupled to the inverting inputs of the power amplifiers IC14- IC15-
IC17. At the same inputs we find :
- a DC voltage coming from P2 and P3, these are factory set coarse alignments.
These coarse alignments also reduce the range of the BELLA potentiometers,
thus increasing the resolution of the digital control.
- the vertical shift voltages controlled by the BELLA IC401 on the subunit, G shift,
R shift and B shift. The red and blue beam will follow the green shift, because a
portion of the green shift voltage is fed to the red and blue shift lines.
- a sawtooth which is proportional with the deflection currents. This is the voltage
across the feedback resistors R145, R131 and R110. These are used to stabilise
the vertical amplitudes.
The TDA8172 allows for a short vertical retrace time by doubling the supply voltage
during retrace.
b. Vertical scan fail detection
a. Power amplifiers
Summary of Contents for GRAPHICS 1209S
Page 4: ...BARCO PROJECTION SYSTEMS GRAPHICS 1209S 90 00972 230V AC 90 00977 120V AC SAFETY NOTICE...
Page 9: ...BARCO PROJECTION SYSTEMS GRAPHICS 1209S 90 00972 230V AC 90 00977 120V AC GENERAL INFORMATION...
Page 28: ...BARCO PROJECTION SYSTEMS GRAPHICS 1209S 90 00972 230V AC 90 00977 120V AC SERVICE SHEETS...
Page 31: ......
Page 32: ......
Page 41: ......
Page 42: ......
Page 43: ......
Page 44: ......
Page 45: ......
Page 46: ......
Page 47: ......
Page 48: ......
Page 49: ......
Page 50: ......
Page 51: ......
Page 52: ......
Page 71: ......
Page 72: ......
Page 73: ......
Page 74: ......
Page 75: ......
Page 89: ......
Page 90: ......
Page 91: ......
Page 98: ...Date 10 02 98 R762720 R G B Driver R762720 1 SERVICE SHEET...
Page 99: ......
Page 100: ......
Page 101: ......
Page 102: ......
Page 103: ......
Page 104: ......
Page 105: ......
Page 120: ......
Page 121: ......
Page 122: ......
Page 123: ......
Page 124: ......
Page 125: ...Date 10 02 98 R762839 RGB Output ABL CRT R762839 1 SERVICE SHEET...
Page 126: ......
Page 127: ......
Page 128: ......
Page 129: ......
Page 142: ...Date 10 02 98 R7625115 Controller module R7625115 1 SERVICE SHEET R7625115 r00...
Page 143: ......
Page 144: ......
Page 145: ......
Page 146: ......
Page 147: ......
Page 148: ......
Page 149: ......
Page 157: ...Date 10 02 98 762457 Deflection Switching Module 762457 1 SERVICE SHEET...
Page 158: ......
Page 159: ......
Page 166: ...Date 10 02 98 R7621127 Sync Vertical Deflection R7621127 1 SERVICE SHEET...
Page 167: ......
Page 168: ......
Page 169: ......
Page 170: ......
Page 171: ......
Page 172: ......
Page 173: ......
Page 194: ......
Page 195: ......
Page 198: ......
Page 199: ......
Page 200: ......
Page 203: ...Horizontal Deflection 1 Date 10 02 98 R7621085 R7621085 SERVICE SHEET R7621085S...
Page 204: ......
Page 205: ......
Page 206: ......
Page 207: ......
Page 208: ......
Page 222: ......
Page 223: ......
Page 224: ......
Page 225: ......
Page 226: ......
Page 227: ......
Page 241: ......
Page 242: ......
Page 243: ......
Page 244: ......
Page 245: ......
Page 246: ......
Page 247: ......
Page 248: ......
Page 249: ......
Page 267: ......
Page 268: ......
Page 271: ......
Page 272: ......
Page 273: ......
Page 282: ......
Page 283: ......
Page 284: ......
Page 292: ......
Page 293: ......
Page 294: ......
Page 295: ......
Page 307: ...Date 18 06 96 R762284 Power mains input module R762284 1 SERVICE SHEET Rev 01...
Page 308: ......
Page 309: ......
Page 314: ......
Page 315: ......
Page 316: ......
Page 328: ......
Page 329: ......
Page 339: ...Date 10 02 98 R7627591 Frame cpl R7627591 1 SERVICE SHEET R806430...
Page 340: ......
Page 341: ......
Page 354: ...Date 10 02 98 R761781 IR Receiver module R761781 1 SERVICE SHEET IRRECEPTION IRRECEPTION...
Page 355: ......
Page 359: ...Date 10 02 98 R762510 IR RS 232 Communication module 1 R762510 SERVICE SHEET...
Page 360: ......
Page 361: ......
Page 362: ......
Page 366: ......
Page 374: ......
Page 375: ......