Service manual

CA-20
CA CIRCUIT DESCRIPTIONS
resulting waveform for yoke current is a sawtooth with rounded peaks.
Vertical Amplification
Most of the vertical signal amplification is performed by the vertical amplifier, IC2100. This IC contains a
power amplifier, a ramp generator, and a flyback generator and is supplied by +25 volts to pin 10. The
initial vertical drive signal which should run at 60 Hz is developed from ICX2200, the video processor. Pin
24 of ICX2200 is the vertical ramp (VRamp) source. This signal is inverted by Q6002 and sent as vertical
sync to pin 2 of IC6000. It also travels as vertical drive to pin 3 of IC2100 through R2101. The vertical
output signal to the yoke comes from pin 1.
<<Figure CA-19>>
Ramp
Generator
Voltage
Regulator
Power
Amp
Buffer
Stage
Thermal
Protection
Flyback
Generator
R3
1
2
3
4
5
6
7
8
9
10 11
Clock
Pulse
IC2100
R2101
R2104
C2130M
C2101
R2103
C2102
R2106M
R2107M
R2105
C2103
R2108
R2109M
R2110M
R2111M
CX2105
DX2101
CX2110
RX2117
C2106
R2118 R2119
R2114
R2112M
R2113
RX2115
RX2116
C2104
C2108
C2107
+25 V
Vertical Rate
Drive for Pin
Correction
To CRT
Protection
Circuitry
Vertical
Output
Vertical
ABL
Vertical
Size
Vertical
Drive
Vertical size is also amplified within IC2100. IC6000 controls vertical size using a pulse width modulated
signal emitted from pin 48. The signal generates a DC voltage across C2101. This DC controls vertical
height using circuitry inside IC2100. As the width of the pulse changes, a corresponding change occurs in
the DC level. In this manner, vertical size may be controlled in the on-screen servicers menu.