High Tension Regulator Confirmation; Protection Circuit Confirmation; Hv Protector Circuit Confirmation; Protector Circuit Confirmation - Sony TRINITRON PVM-14L5 Service Manual

3-1. High Tension Regulator Confirmation

1. Turn the POWER OFF.
2. Connect an electrostatic voltmeter to anode cap of
CRT tube.
Electrostatic voltmeter : It must have input impedance
of 2 x 10 9 Z and have already been calibrated.
(Example : Singer ESH-27X or ESH-23X)
3. Supply AC power voltage of 130 V
turn the POWER ON.
4. Input a 480/60i monoscope signal.
5. Press the BRIGHTNESS button and the CONTRAST
button to put the unit into the PRESET state (center value).
6. Confirm that the high tension voltage value satisfies
the standard value.
Standard value : 22.0 ± 1.0 kV (14 inch)
26.5 ± 1.0 kV (20 inch)

3-2. Protection Circuit Confirmation

3-2-1. HV Protector Circuit Confirmation

1. Supply AC power voltage of 130 V
turn the POWER ON.
2. Input a 480/60i all-black signal and set the BRIGHT
and CONTRAST VRs on the User Control screen of
the menu, to MIN.
G board (B side)
R 5 1 6
3-2
to the unit and
AC
to the unit and
AC
R 5 5 5
R 5 2 6
R 5 2 9
R 5 3 8
R 5 3 0
R 5 2 7
Q 5 0 1 Q 5 0 2 Q 5 0 3
R 5 2 8
R 5 3 9
R 5 4 4 I C 5 0 4
R 5 3 2
C 5 0 4
3. Confirm that the voltage between the cathode and GND
of D501 on the G board satisfies the standard value.
Standard value : 20.5 ± 1.5 V
24.5 ± 1.5 V
4. Apply the following voltage between the cathode and
GND of D501 on the G board, and confirm that the
protector circuit is not activated.
23.0 ± 0.5 V
(14 inch)
DC
26.0 ± 0.5 V
(20 inch)
DC
5. Apply the following voltage between the cathode and
GND of D501 on the G board, and confirm that the
protector circuit is activated and raster disappears.
25.5 ± 0.5 V
(14 inch)
DC
30.5 ± 0.5 V
(20 inch)
DC
6. Input a 480/60i all-white signal and set the BRIGHT
and CONTRAST VRs on the User Control screen of
the menu, to MAX.
7. Confirm that the voltage between the cathode and GND
of D501 on the G board satisfies the standard value.
Standard value : 22.0 ± 1.5 V
26.5 ± 1.5 V
3-2-2. 1K Protector Circuit Confirmation
1. Supply AC power voltage of 130 V
turn the POWER ON.
2. Input a 480/60i all-black signal.
3. Press the BRIGHTNESS button and the CONTRAST
button to put the unit into the PRESET state (center
value).
4. Connect a constant current source to the center point
between R527 and R528 on the G board and let the
current of _1,500.0 uA flow into the circuit. Confirm
that the protector circuit is activated and raster disap-
pears.
Digital VOM
Constant
current
_
sourcce +
R 5 1 8
Fig3-1
(14 inch)
DC
(20 inch)
DC
(14 inch)
DC
(20 inch)
DC
to the unit and
AC
PVM-14L5/20L5/D14L5A/D20L5A