CPD-420GS/GST
—14—
When replacing parts shown in the table below,
the following operational checks must be
performed as a safety precaution against X-ray
emissions from the unit.
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 the High Voltage within
specification, put the RV cover on RV904 as
shown below and apply sufficient amount of RTV
around RV904.
b)
HV Hold-Down Check
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:
120 + 2 VAC
•
Input signal:
(fH = 94 kHz), White Cross Hatch
•
Controls:
CONT (max) & BRT (min)
•
B+ Voltage:
181 + 4.0 VDC
c)
Beam Protector Check (Software logic)
1.
Using an external current source, apply 1.30
+ 0.05 mA between pin
of FBT (T501) and
GND, and confirm that the voltage at CN801 pin
is 2.25 VDC or less.
Check Condition
•
Input voltage:
120 + 2 VAC
•
Input signal:
(fH = 94 kHz), White Cross Hatch
•
Controls:
CONT (max) & BRT (min)
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
D - BOARD
Part Replaced ( )
RV904
Part Replaced ( )
T901, R903, IC805, R921, R922, R812, D908,
IC605, R913, R914, D802, D909
•
•
•
•
10
4
R V 5 0 1
RV904
11
1
SECTION 3
SAFETY RELATED ADJUSTMENT
Содержание Trinitron CPD-420GS
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