Goldstar MONOCHROME MONITOR MBM-2105GIA Service Manual page 4

3. COMPOSITE VIDEO INPUT AND HORIZONTAL/
VERTICAL DEFLECTION
3-l VIDEO INPUT (PIN 15)
The detection level for negative sync pulse at the
sync separation input (pin 15) is set at 1.6V. When
the voltage at emitter of the Transistor (pin 15) is
above
lower than 1.6V enables the transistor to conduct
a n d t h e internal
synchronization function.
3-2 COMPOSITE VIDEO INPUT (PIN 15)
Vertical
Oscillator
Oscillator
Frame-Synchro
Line Fly Back Phase
Input
Figure 4, BLOCK DIAGRAM OF THE TEA 2037A
circuitry
i s enabled for
vcc 2
Vcc 2 Generator
Horizontal
Oscillator
Detector
LINE (H) OSCILLATOR (PIN 9)
3-3
The line oscillator is of the type which charges and
discharges a capacitor, since a perfectly linear
sawtooth wave form is not required.
The free running frequency is dependent on C705,
R705 and VR702 and is governed by this expres-
sion To = 085 x C705 x R705 where To is the line
oscillator free running frequency.
FRAME(V) OSCILLATOR (PIN 9)
3-4
Oscillator thresholds
resistor C601, R603 are used to determine the
free-running frequency,
free-running frequency is given by To = 0.15 x
Generator
Vertical
o u t p u t
P o w e r
Amplifier
Input
Horizontal
o u t p u t
are internally fixed
the oscillator
by