Sony CPD-4201M, Service Manual, Page: 13 / 50

— 13 —
CPD-4201M
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 (center)
• 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 11 of FBT
(T501) and GND, and confirm that the voltage
at CN801 pin 1 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 (center)
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
SECTION 3
SAFETY RELATED ADJUSTMENT
Part Replaced ( )
RV904
Part Replaced ( )
D - BOARD
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) Minimum CONT and BRT controls.
3) Cut off Screen VR (G2).
4) Input voltage: 120 ± 2 VAC
5) Confirm that the voltage is within the voltage range
shown below.
Standard voltage: 27.0KV ± 0.2KV
6) When replacing components identified by , make
sure to recheck the High Voltage.
7) 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.
8) After adjusting the High Voltage within specification,
put the RV cover on RV904 as shown below and apply
sufficient amount of RTV around RV904.
T901, R903, IC805, R921, R922, R812, D908, IC605,
R913, R914, D802, D909
RV904