Sony Trinitron PVM-14N5U - Protection Circuit (Hold-Down Circuit) Check

4-2
SIIA Chassis
4-2. PROTECTION CIRCUIT (HOLD-
DOWN CIRCUIT) CHECK
Note: Be sure to use the NF power supply. If not, use
an ordinary power supply of its distortion
factor is 3% or less.
1. Protection Circuit Normal Operation Check
Input voltage: 120 ± 3 Vac
Input signal: Black
Controls: BRIGHTNESS 8 Minimum
CONTRAST 8 Minimum
Specification: Confirm that the voltage at Cathode of
D103 on the A board and ground is
greater than 99.0 Vdc.
2. Protection Circuit Operation Check (1)
Input voltage: 130 Vac
Input signal: Black
Controls: 14-inch: IABL = 40 ±20 µA
20-inch: IABL = 120 ±20 µA
Specification: Apply following voltage to Cathode of
D103 on the A board from the external
DC power supply and make sure that the
hold-down circuit doesn’t work.
14-inch: 119.6
+0
Vac
_0.4
20-inch: 145.2
+0
Vac
_0.4
3. Protection Circuit Operation Check (2)
Input voltage: 130 Vac
Input signal: Black
Controls: 14-inch: IABL = 40 ±20 µA
20-inch: IABL = 120 ±20 µA
Specification: Apply following voltage to Cathode of
D103 on the A board from the external
DC power supply and make sure that the
hold-down circuit works.
14-inch: 128.4
+0
Vac
_0.4
20-inch: 156.6
+0
Vac
_0.4