4
1. Remote VR PCB
Contrast, VR720
Brightness, VR721
H-Position, VR722
H-Size, VR723
V-Size, VR724
V-Position, VR725
2. Main PCB
Horizontal OSC, VR301
V-HOLD, VR303
V-LIN, VR302
3. Flyback Transformer
Focus Ad justment
Screen Ad justment
4. Neck PCB
Red Cut-off, VR552
Red Gain, VR551
Green Cut-off, VR555
Green Gain, VR553
Blue Cut-off, VR554
Blue Gain, VR556
These cont rols in main, neck PCB and flyback transformer have been preset and sealed at the factory
and should not require further attention.
The c has sis of this color monitor has been
designed to emit a minimum of soft X-radiation,
in accordance with US DHHS rules 21 CFR,
subchapter J, applicable at date of manufacture
A high voltage shut-down circuit, as shown
below, guarantees horizontal oscillation shut-
down.
A flyback pulse is generated at pin 10 of flyback
trans former. This pulse is fed through a
resistive divider network to pin 13 of I301.
The voltage appearing on pin 13 is compared
with a precise internal voltage in the IC should
the EHT exceed 28KV the change in voltage on
pin 13 actuates a c i rcu i t which inh i b i ts the
oscilator and consequently the EHT circuit.
The circuit continues to inhibit the oscillator
until the fault condition is corrected, and even
then the monitor has to be switched off and on
cillator cable is re-activated.
HIGH VOLTAGE SHUT-DOWN CIRCUIT
CONTROLS
