CPD-E250 - Sony Monitor Service Manual (repair manual). Page 9

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CPD-E250
2-2.  HV PROTECTOR CIRCUIT CHECK
1. Confi rm that the voltage between cathode of D517 and GND is 
more than 27.0 VDC.
2.  Using an external DC Power supply,  apply the volt age shown 
below between cathode of D517 on D Board and GND, and 
confi rm that the HV Hold-Down circuit works (Raster disappears).  
Apply DC Voltage: Less than 35.9 VDC.
       Check Condition
       • Input voltage:     120 ± 2 VAC
       • Input signal:       (fH =69 kHz), White Cross Hatch
       • Controls:            CONT (max) &  BRT (center)
       • B+ Voltage:        179 ± 3.0 VDC
2-3.  BEAM PROTECTOR CHECK  
(SOFTWARE LOGIC)
1.  Using an external current source, apply < 1.55mA between 
pin 
11
 of FBT (T501) and GND, and confi rm that the raster 
fades out.
       Check Condition
       
• Input voltage:     120 ± 2 VAC
       • Input signal :      (fH = 69 kHz), White Cross Hatch
       • Controls:            CONT (max) &  BRT (center)
2-4.  B+ VOLTAGE CHECK
1.  Input white cross hatch (fH = 69 kHz) signal.
2.  CONT (max) &  BRT (center).
3.  Input voltage: 110 ± 10 VAC.
 
Note:  Use NF power supply or make sure that dis tortion factor 
is 3% or less.
4. Confi rm that the voltage is within the range shown below:
Standard voltage: 179 ± 3.0 VDC 
SECTION  2: SAFETY RELATED ADJUSTMENTS
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.
Part Replaced (    ) 
HV ADJ
RV501
Part Replaced (    ) 
D Board   
T501, IC501, RV501, R540,
R541, R542, R544, R564, R567,
R568, C532, C534, C539, C553,
C554, C555, C556, C558, C561
HV Regulator
Circuit
D Board   
T501, R510, R543, R547, R549,
R552, R595, D515, D517, C540,
C542, C544, IC607, IC901, C951  
HV HOLD
DOWN Circuit 
D Board   
T501, R545, R546, R548, R550,
R596, R934, C535, C541, IC605,
IC607, IC901  
Beam Current
Protector Circuit
 
Allow the unit to warm up for one minute prior to checking the 
following conditions.
2-1.  HV REGULATOR CHECK
1.  Input white cross hatch signal (fH = 80 kHz).
2.  CONT maximum and BRT center.
3.  Cut off Screen VR (G2).
4.  Input voltage: 120 ± 2 VAC.
5. Confi rm that the voltage is within the voltage range shown below:
 
  
Standard voltage: 26.0 +0.3, -0.5 kV
6.  When replacing components identifi ed by Y , make sure to 
recheck the High Voltage.
7.  Verify the High Voltage as shown above (26.9 +0.3, -0.5 kV) is 
within specifi cation.  If not, set H. SIZE data at  minimum (-127) 
and then adjust RV501 on D Board 
(Adjustment target = 26.0 ± 0.2 kV).
8.  After adjusting the High Voltage within specifi cation, put the RV 
cover on RV501 as shown below and apply suffi cient amount of 
RTV around RV501.
RV501
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