Sony TRINITRON BVM-14G1A Operation And Maintenance Manual page 91

3. Protection Circuits
3-1. H.STOP, V.STOP Detection Circuit
The current flowing to the horizontal deflection york is con-
verted to the parabola voltage of the horizontal period by
C065. This parabola voltage is used to switch Q121. The
C122 voltage charged by R122 is discharged in the horizon-
tal period by Q121 so that it does not reach the voltage for
turning on Q122. When an error occurs in the horizontal de-
flection circuit, the voltage of C122 is used to turn on Q122
since Q121 does not turn on. Q122 turns off IC503 and stops
the high voltage generation circuit by setting pin 8 of IC503
to "Low".
The current flowing to the vertical deflection york is con-
verted to the sawtooth voltage of the vertical period by R035.
This sawtooth voltage is used to switch Q132, Hereafter the
operations are the same as the horizontal block.
4. Correction Signal Generation Circuit
4-1. Convergence Correction Signal Generation
Circuit
IC201 generates the convergence correction signal. It out-
puts the vertical convergence correction signal, horizontal
convergence correction signal of the vertical period, H STAT
adjustment voltage, landing adjustment voltage, and parabola
signal of the vertical period.
IC202 and IC204 consist of the circuit generating the sawtooth
signal of the horizontal period and the integral circuit. They
output the sawtooth signal of the horizontal period, parabola
signal, and sine signal.
IC701 is an integrated circuit consisting of a multiplier, sig-
nal switching circuit, and OP AMP amplifier. IC703 is DA
converter which outputs the d.c. voltage. IC701 modulates
the parabola signal of the horizontal period using the parabola
signal of the vertical period, varies the level using the DAC
output of IC703, and outputs the horizontal convergence cor-
rection signal of the horizontal period.
IC703 outputs the rotation adjustment voltage.
4-2. Horizontal Linearity Correction Signal,
Dynamic Focus Signal Generation Circuit
IC151 and IC301 an integrated circuit consisting of a multi-
plier, signal switching circuit, and OP AMP amplifier. IC205
is a D/A converter which outputs d.c. voltage. IC301 varies
the level of the parabola signal of the vertical period using
the DAC output of IC205 and outputs the dynamic focus sig-
nal of the vertical period. It also modulates the parabola sig-
nal of the horizontal period using the parabola signal of the
vertical period whose level has been varied using the DAC
output of IC205 and the signal obtained by adding level us-
ing the DAC output of IC205, and outputs the dynamic focus
signal of the horizontal period.
IC151 and IC301 adds the parabola signal of the horizontal
period whose level was varied using the DAC output of IC205,
the sine signal of the horizontal period whose level was var-
ied using the DAC output of IC205, and the signal modu-
lated by the parabola signal of the vertical period in which
the level of the two signals was varied using the DAC output
of IC205, and outputs the horizontal linearity
signal.
5. Control Circuit
The SUB CPU (IC7001) performs serial communication with
the system control CPU of the BC board using the three sig-
nals MISO, MOSI, and SCLK, and outputs the control sig-
nals POWER ON, DEGAUSE, AFC SW, H.DELAY,
V.DELAY, etc. according to the instructions of the system
control CPU (BC board IC1). It also reads the adjustment
data of the EEPROM (IC7004) and output the adjustment
voltage from the D/A converter (IC7005). In addition, it also
controls the waveform output from IC112, IC115, and IC118
of the D board. The following protect detection signals are
transmitted to the system control CPU from the SUB CPU.
H.STOP, V.STOP, +B.PROT, HV_OVP
IK_PROT, HV_OVP, G.PROT1 to 4
6-5