Read Sony GDM-500PS / GDM-500PST Service Manual online
– 18 –
GDM-500PS/500PST
SECTION 3
SAFETY RELATED ADJUSTMENT
When replacing or repairing the shown below table, the
following operational checks must be performed as a
safety precaution against X-rays emissions from the unit.
a) HV Regulator Circuit Check
1) Confirm that the voltage of the pin 2 of CN901 on D
board is within the voltage range shown below.
Standard: 9.00 ± 0.065 VDC
b) HV Protector Circuit Check
1) Confirm that the HV protector circuit works and TV
Raster disappears when apply the voltage as shown
below between pin 3 of CN901 on D board and
GND using an external DC power supply.
Check Condition: Less than 34.10 VDC
c) Beam Current Protector Circuit Check-1
1) Measure HV voltage and record that value.
2) Shorted between pin 1 and pin 4 of CN901 on D
board.
3) Connect to the Constant Current Jig (A) between pin
1 of CN901 on D board and GND, confirm that the
Beam Current Protector Circuit works and HV go
Beam Current Protector Circuit works and HV go
down more than 1.25 kV from the value of (1).
Check Condition: 1.50 mA
d) Beam Current Protector Circuit Check-2
1) Connect to the Constant Current Jig (B) between pin
1 of CN901 on D board and GND, confirm that the
Beam Current Protector Circuit works and TV Raster
Beam Current Protector Circuit works and TV Raster
disappears.
Check Condition: 1.59 mA
e) Voltage of 3rd winding of FBT
1) Confirm that the voltage of pin 3 of CN901 on D
board is within the voltage range shown below.
Standard: more than 28.0 VDC
HV Regulator
Circuit Check
Circuit Check
HV Protector
Circuit Check
Circuit Check
Beam Current
Protector Circuit
Check
Protector Circuit
Check
Part Replaced (
]
)
D Board IC901, T902
• Mounted D board
D Board Q660, Q661, D916,
D935, C924, R665,
R667, R940, R980,
T902
• Mounted D board
R667, R940, R980,
T902
• Mounted D board
G Board PH680, Q680, Q683,
D680, R680, R685,
R686, R687, R688,
R689
• Mounted G board
R686, R687, R688,
R689
• Mounted G board
D Board IC901, D904, D907,
D908, R011, R908,
R909, R921, R925,
R926, R929, R930,
T902
• Mounted D board
R909, R921, R925,
R926, R929, R930,
T902
• Mounted D board
Check Condition
Input voltage : 100 ~ 240 VAC
Input signal : White Cross Hatch at 107 kHz
Beam control : BRT and CONT
→
Minimum
B+ voltage
: 195 ~ 205 VDC
Click on the first or last page to see other GDM-500PS / GDM-500PST service manuals if exist.