Safety Related Adjustment - Sony Trinitron CPD-420GS Service Manual

CPD-420GS/GST
When replacing parts shown in the table below,
the following operational
performed as a safety precaution against X-ray
emissions from the unit.
D - BOARD
Part Replaced ( )
RV904
Part Replaced ( )
T901, R903, IC805, R921, R922, R812, D908,
IC605, R913, R914, D802, D909
•
Allow the unit to warm up for one minute prior to
•
checking the following conditions:
a) HV Regulator Check
1. Input white cross hatch signal. (fH = 94 kHz)
2. Maximum CONT and BRT controls.
3. Input voltage: 120 + 2 VAC
4. Confirm that the voltage is within the voltage
range shown below.
Standard voltage: 27.0KV + 0.2KV
5. When replacing components identified by
make sure to recheck the High Voltage.
6. Verify the High Voltage as shown above (27.0KV
+ 0.2KV) is within specification. If not, set H. SIZE
data at minimum (-127) and then adjust RV904 on
"D" Board.
7. After adjusting
specification, put the RV cover on RV904 as
shown below and apply sufficient amount of RTV
around RV904.
SECTION 3

SAFETY RELATED ADJUSTMENT

checks must
the High Voltage within
RV904
R V 5 0 1
b) HV Hold-Down Check
be
1. Using an external DC Power supply, apply the
voltage shown below between cathode of D908
on "D" Board and GND, and confirm that the HV
Hold-Down circuit works. (Raster disappears).
Apply DC Voltage: 21.5 + 0.5 VDC.
Check Condition
• Input voltage:
• Input signal:
• Controls:
• B+ Voltage:
c) Beam Protector Check (Software logic)
1. Using an external current source, apply 1.30
+ 0.05 mA between pin
GND, and confirm that the voltage at CN801 pin
is 2.25 VDC or less.
1
Check Condition
• Input voltage:
• Input signal:
• Controls:
,
d) B+ MAX. Check
1. Input white cross hatch (fH = 94 kHz) signal.
2. CONT (max) & BRT (center)
3. Input voltage: 120 + 2 VAC
Note: Use NF power supply or make sure that
distortion factor is 3% or less.
4. Confirm that the voltage is within the voltage
range shown below.
Standard voltage: 181 + 4.0 VDC
—14—
120 + 2 VAC
(fH = 94 kHz), White Cross Hatch
CONT (max) & BRT (min)
181 + 4.0 VDC
of FBT (T501) and
11
120 + 2 VAC
(fH = 94 kHz), White Cross Hatch
CONT (max) & BRT (min)