Driver Amplifier
Circuit Description
(Serial Number Prefixes: 3004A and Above)
Y Deflection Amplifier
The Y deflection amplifier consists of a single ended to differential voltage to current amplifier
which drives two current to voltage output stages. The result is a differential voltage
output to drive the positive and negative Y deflection plates of the CRT. The output has an
average (common mode) voltage of approximately 55 V (equal to the first accelerator voltage
of the CRT).
The voltage to current Y Preamplifier consists of a differential pair
and Q114 with a
constant current emitter bias supplied by Q115. R127 is used to adjust the collector bias to
position the beam in the center of the CRT when the input voltage is 1 V. This adjustment
also makes up for gun misalignment in the CRT.
and
are voltage gain stages and
and
are voltage to current converters
that drive a virtual ground input to the two current to voltage output stages with equal
but opposite signals. The gain of the
and
stage is determined by the emitter
resistance. The differential gain is adjusted by R120 and
and the common mode current
is set by R118 and R120.
The current to voltage stages, and are identical so only Y+ Current to Voltage
Amplifier is described. The Y+ amplifier consists of an active load (constant current
source) made up of
R102 and R104 and a pull down transistor Q102. R102
and R104 set the base voltage of
to a nominal dc level.
in the emitter of
sets the current in the collector. Q102 is biased on by R102 and R104 and is held in linear
operation by the emitter of Q104. R106 is the gain setting feedback resistor that maintains
closed loop operation. R108 biases the current to voltage amplifier input to set the minimum
output voltage to about 5.7 V with no collector current from
=
1 5 v
In general, the output voltage of the current to voltage stage is determined by the current
drawn from the input by
This current is supplied by the feedback resistor R106. R106
is a 23.7 k resistor so the output voltage will rise 23.7 V for each milliamp of current drawn
from the input node.
Q103 is a feed forward circuit to help speed up transient response. A rise or fall in input
signal voltage will pass through the emitter follower formed by Q103 and R105 and then are
ac coupled through
and
to the base of Q102.
also couples this voltage to the
base of
With the emitter bypassed against rapid voltage changes by
the active
load current is also modulated to help the ac response of the output stage.
CR102, CR103, R140 and spark gap
are an output protection network to protect the
amplifier from arcs inside the CRT or in the cabling to the CRT.
3
Содержание 85662A
Страница 13: ......
Страница 14: ......
Страница 17: ...can cause the CRT to be disabled If U14 is operating correctly visually inspect the A4A9 assembly Al 3 ...
Страница 18: ......
Страница 27: ......
Страница 28: ...AlA KEYBOARD Al Front Panel Assembly and Component Locations ...
Страница 30: ......
Страница 49: ......
Страница 51: ...3 AlA XYZ Driver Amplifier Component Locations 85662 60236 ...
Страница 52: ......
Страница 53: ......
Страница 54: ......
Страница 72: ......
Страница 73: ......
Страница 77: ......
Страница 78: ......
Страница 84: ......
Страница 92: ...V I E W A AlA lII1 0 O0 4 JII fi V I E W B Figure 1 IF Display Section internal Fuse Replacement 8 Al A6 Al A7 ...
Страница 108: ......
Страница 109: ......
Страница 111: ...I 1 AlA f15 V Regulator Component Locations 85662 60232 85662 60250 ...
Страница 113: ......
Страница 114: ......
Страница 115: ......
Страница 122: ......
Страница 124: ...DSl M A I N S I N D I C A T O R C6 CATHODE 4 1 El r l CR9 P I AlA Rectifier Component Locations 85662 60204 ...
Страница 125: ...c 4 C 6 R 6 I 0 C R 9 0 CR10 AlA Rectifier Component Locations 85662 60234 ...
Страница 126: ...0 El E2 r r L J L J _ I 0 0 0 0 AlA Bus Transition Component Locations 85662 60056 ...
Страница 127: ......
Страница 128: ......
Страница 129: ......
Страница 131: ......
Страница 133: ......
Страница 142: ......
Страница 161: ......
Страница 163: ......
Страница 178: ......
Страница 179: ... R51 Y S H BAL R50 X S H BAL R12 LL THRESH A3A2 Intensity Control Component Locations 85662 60025 85662 60245 ...
Страница 180: ......
Страница 181: ......
Страница 195: ......
Страница 196: ...R 8 YSL L Il ln R IC7n XSL 0 0 0 R 5 I I Y G A I N R 2 Y E X P A3A3 Line Generator Component Locations 85662 60128 ...
Страница 198: ......
Страница 203: ......
Страница 205: ......
Страница 210: ......
Страница 212: ......
Страница 216: ...Verify binary count sequence starting at the least significant bit SO 500 ns square wave to S7 64 ps square wave 4 A3A6 ...
Страница 219: ......
Страница 221: ......
Страница 226: ......
Страница 228: ......
Страница 241: ......
Страница 256: ......
Страница 258: ...R 5 7 T H G A I N R59 T H O F S A3A9 Track and Hold Component Locations 85662 60165 ...
Страница 259: ......
Страница 260: ......
Страница 262: ...ASXAlPI I A3XA2P 1 AJXAJP 1 A3XA4P 1 A3XA5P 1 A3XA6Pl A3XA7P 1 A3XA9P 1 AJXAlP2 A3XA2P2 A3XASP2 A3XA6P2 A3XA7P2 ...
Страница 263: ......
Страница 266: ......
Страница 274: ......
Страница 275: ...R2 LG OS p 10 C6 I I R14 ar OS 1 5 1 A4Al Video Processor Component Locations 85662 60122 ...
Страница 276: ......
Страница 293: ......
Страница 294: ...2 k 4 5 7 J2 F1 TEN R91 12VTV R14 LG 20 A4A2 Log Amplifier Detector Component Locations 85662 60132 ...
Страница 295: ...2 4 5 1 0 N a R79 ZERO 4 E N TV R14 LG 20 A4A2 Log Amplifier Detector Component Locations 85662 60166 ...
Страница 296: ......
Страница 297: ......
Страница 315: ......
Страница 316: ...10 A 1 2V T Y P 7 V T Y P A4A3 Log Amplifier Filter Component Locations 85662 60009 ...
Страница 318: ......
Страница 319: ......
Страница 321: ... 15v t15v cl7 ETC Figure 2 A4A4 Input Buffer Amplifier Current Sinks 2 A4A4 ...
Страница 334: ......
Страница 336: ...c 4 3 L C D I P c41 L C D I P A4A4 Bandwidth Filter Component Locations 85662 60189 TR ...
Страница 337: ......
Страница 338: ......
Страница 352: ......
Страница 354: ......
Страница 363: ......
Страница 365: ...A4A8A2 Down Converter Component Locations 85662 60005 ...
Страница 366: ...c31 R29 1 8 4 M H z NULL W I D E G A I N A4A6Al Up Converter Component Locations 85662 60006 ...
Страница 367: ......
Страница 379: ...c40 c 4 1 PK SYM y Hz A M P L 10 Hz AMPL A4A7 3 MHz Bandwidth Filter Component Locations 85662 60004 85662 60174 ...
Страница 380: ......
Страница 399: ......
Страница 402: ......
Страница 403: ......
Страница 409: ...Table 4 Video Bandwidth Truth Table 6 A4A9 ...
Страница 428: ......
Страница 429: ......
Страница 430: ......
Страница 434: ......
Страница 447: ......
Страница 452: ...A4A6A2 Output Driver Component Locations 85662 60170 Option 067 Tab ...
Страница 453: ...A4A6Al Input Buffer Component Locations 85662 60171 Option 067 Tab ...
Страница 454: ......
Страница 470: ......
Страница 473: ...Table 4 Video Bandwidth Truth Table Option H96 3 ...
Страница 498: ......
Страница 504: ...Table 4 Video Bandwidth Truth Table 100 Hz H 30 Hz H H 10 Hz H 3 Hz H 1 Hz 6 Option 462 ...
Страница 514: ......
Страница 523: ......
Страница 531: ......
Страница 548: ......
Страница 549: ......
Страница 550: ......
Страница 582: ...This page intentionally left blank 32 General Parts Listing ...
Страница 594: ...HEWLETT PACKARD HP Part No 85662 90085 Printed in USA ...