Model 185B Section IV
Paragraphs 4-101 to 4-108
- OUTPUT - TO VERTICAL
AMPLIFIER DEFLECTION
v3 PLATES OF CRT 4
t d
CATHODE CATHODE
FOLLOWER FOLLOWER
VIA V2A
1L 1L
DIFFER- += DIFFER- 4
INPUT FROM I INPUT FROM
ENTIAL ENTIAL
CHANNELA j CHANNEL B
AMPLIFIER AMPLIFIER
OF PLUG-IN - * OF PLUG-IN
01/02 03/04
CATHODE CATHODE
FOLLOWER FOLLOWER
V2B
-
VERTICAL MULTI- BLANKING
PRESENTATION
VIBRATOR e AMPLIFIER - PULSE
SWITCH IN e---
v4 BLANKING v5 TO CRT
PLUG-IN
- PULSE . b
1 BLANKING
PULSE FROM BD-Y-273
PLUG-IN
Figure 4-11. Vertical Amplifier Block Diagram
4-101. TRANSIENTS. 4-108. The series regulator in each supply acts as
a variable resistor in series with the supply output.
4-102. To prevent switching transients from appear- A comparison or differential amplifier senses any
ing on the crt, a negative pulse generated by multivi- change in the output voltage by comparing the output
brator V4 is applied to amplifier V5 and then to the against a fixed reference voltage. The amplifier then
crt to blank the crt during switching time. During changes the resistance of the series regulator in a
sampling, the vertical plug-in unit sends a blanking way that opposes the change in output voltage. The
pulse to amplifier V5; this pulse prevents sampling power supplies are transistorized. Emitter followers
transients from appearing on the crt. are required between amplifier and series regulator
to amplify the current to the level required to drive
the series regulator.
4-103. HIGH-VOLTAGE POWER SUPPLY.
4-104. The high-voltage power supply (figure 4-12) +250V
provides voltage (-2900 volts) required to operate the *
crt. An rf oscillator, V302, oscillates at approxi-
mately 80 kc. High-voltage transformer T301 steps n
AMPLIFIER
up oscillator output to a high ac voltage which rectifies V301
V303 and V304 and their associated rc filters convert
to dc. The dc voltages are applied to the crt. Regu-
lator V301 compares output of the crt cathode supply
with +250 volts and changes amplitude of rf oscilla-
tions to oppose any high-voltage change relative to
the 250 volts.
4-105. The crt is normally biased on. Blanking
pulses from V5 (paragraph 4-102) blank the crt to
prevent undesirable transients from appearing.
4-106. LOW-VOLTAGE POWER SUPPLIES. TO CRT
GRID
4-107. The low-voltage power supplies include one
independent supply and four dependent supplies. The BLANKING- 2 .E ..*.,
PULSES
-100 volt supply is the independent supply. It is a
reference for the +lo0 volt and +250 volt supplies
and is a supply voltage for the comparison amplifiers Figure 4-12. High-Voltage Power Supply
of the +12.6 volt and -12.6 volt supplies. Block Diagram
01255-1 4-13 |