KV-25FS12 - Sony TV Service Manual (repair manual). Page 14

If the setting indicated in Step 2 of Hold-Down Operation Confi rmation 
cannot be met, readjustment should be performed by altering the 
resistance value of R564 component marked with X. 

+

IABL

ABL

T505

FBT

range

-

ammeter

3.0 mA  DC

A

Note: The following adjustments should always be performed when 
replacing the following components, which are marked with Y on the 
schematic diagram on the A Board:

   A BOARD: 

IC601, PH601

1.  Using a Variac, apply AC input voltage: 130 ± 2 VAC

2.  Input a dot signal.

3.  Set the PICTURE  and the BRIGHTNESS controls to minimum.

4.  Confi rm the voltage of A Board TP-600 is <136 VDC.

5.  If step 4 is not satisfi ed, replace the components listed above, then 

repeat Steps 1 – 3.   

3-1. X R564 CONFIRMATION METHOD  
(HOLD-DOWN CONFIRMATION) AND 
READJUSTMENTS

The following adjustments should always be performed when replacing 
the following components which are marked with Y on the schematic 
diagram:

Part Replaced (   )

Adjustment (   )

DY, T505, CRT, IC501 C507, 
C520, C505, C509, C515, T504, 
T503, C551, L510, C546, C537, 
C547, D517, D518, D519, R560, 
R561, R562, R563, R565, R566, 
R567, R525....................A Board

IC1301........................MB Board

HV HOLD-DOWN
R564

1.  Using a Variac, apply AC input voltage: 120-220 ±2 VAC.

2.  Turn the POWER switch ON.

3.  Input a white signal and set the PICTURE and BRIGHTNESS controls 

to maximum.

4.  Confi rm that the voltage between C546 (+) or TP503 and ground is 

more than 97 VDC. 

1.  Connect the current meter between Pin 11 of the FBT (T505) and 

the PWB land where Pin 11 would normally attach (See Figure 1 on 
the next page).

2.  Input a dot signal and set PICTURE and BRIGHTNESS to minimum: 

IABL = 100 ± 100µA.

3.  Confi rm the voltage of A Board TP-600 is 135 ± 1 VDC.

4.  Connect the digital voltmeter and the DC power supply via Diode 

1SS119 to C546 (+) and ground (See Figure 1 on next page).

5.  Increase the DC power voltage gradually until the picture blanks out.

6.  Turn DC power source off immediately.

7.  Read the digital voltmeter indication (standard < 138 ± 0.3 VDC).

8.  Input a white signal and set PICTURE and BRIGHTNESS to 

maximum: IABL = 1650 ± 100µA.

9.  Repeat steps 4 to 7.