(5-L -2) H Phase Circuit - NEC MultiSync 4FGe Service Manual

5-l-2. Horizontal phase circuit
Horizontal Position is to be adjusted by delaying the Horizontal Sync signal phase input to LA7850. IC5A6's
inputs of H position control voltage and saw tooth waveform are generated from the H sync timing. The duty
comparator's output varies with the H position control voltage. The sync signal phase can be delayed by
triggering to LA7850 on the breaking edge.
SAW TOOTH
(Fig 5-l -3) PARALLEL0 DISTORTION correct circuit and SAW TOOTH OSC circuit
vertical timing through C432, and is adjusted with VR431. This sawtooth waveform pulse is produced at pin @ of
USER
H POS
CONTROL
(Fig 5-l-2) BLOCK DIAGRAM of the H phase circuit
H POS
ADJUST
CIRCUIT
OUTPUT COMPARATOR
TRIGGER
control voltage
CONSTANT
CURRENT
CIRCUIT