Safety Related Adjustments - Sony KV-20V50 Service Manual

A BOARD
DOWN CONFIRMATION)
The following adjustments should always be per-
formed when replacing the following components
(marked with 0 on the schematic diagram).
D511, C523, C524, R534, R535, R537, R549,
R637, PM501, T504, DY
1. Preparation before confirmation
1) Turn the POWER switch ON, and receive
entirely white signal and set the PICTURE and
BRIGHT controls to maximum.
2) Confirm that the voltage of the check terminal of
TP85 is more than 1OOVDC
operating normaly with 120.0 f 2.OVAC
2. Hold-down operation confirmation (HV)
1) Connect the currentmeter between the 7th pin of
FBT (T504)and the land of it with connect
polarity.
2) Receive White Signal and adjust the ABL
current to follows with the PICTURE and the
BRIGHT controls.
1 4 5 0 zh lOOpA
3) Connect the Digital Voltmeter to pin8 of PM501
then read the voltage as A.
4) Connect the Digital Voltmeter and DC power
Supply via 1SS 119 to TP-85.
5) Increase the DC power voltage gradually until
the Picture just blanks out.
6) Read the digital voltmeter indication.
7) Turn DC power Source off immediatery.
STANDARD
Less or equal to
8) Receive Dot Signal and adjust the ABL current
to follows, with the PIX and the BRT controls.
150 + 100 PA
9) Repeat steps from (3) to (7).
STANDARD
Less or equal to
3. Hold-down readjustment
When step 2 is not satisfied, readjustment should
be performed by altering the resistance value of
R537 (a component marked with E).
SECTION 4

SAFETY RELATED ADJUSTMENTS

AND READJUSTMENTS
when the set is
supply.
A + 16.5 VDC
A + 16.5 VDC
A BOARD
q
R511
CONFIRMATION METHOD (B+ HOLD-
DOWN CONFIRMATION)
The following adjustments should always be per-
formed when replacing the following components
(marked with 0 on the schematic diagram).
C524, R511, R534, R549, R637, PM501
1. Hold-Down Operation Voltage (B+)
1) Connect the currentmeter between the 7th pin of
FBT (T504)and the land of it with connect
polarity.
2) Receive White Signal and adjust the ABL
current to follows with the PICTURE and the
BRIGHT controls.
1 4 5 0 + lOOpA
3) Connect the Digital Voltmeter and DC power
Supply via 1SS 119 to pin8 of PM501.
4) Increase the DC power voltage gradually until
the Picture just blanks out.
5) Read the digital voltmeter indication.
6) Turn DC power Source off immediatery.
Less or equal to
7) Receive Dot Signal and adjust the ABL current
to follows, with the PICTURE and the BRIGHT
controls.
150 -t
8) Repeat steps from (4) to (6).
Less or equal to 132.5 VDC
2. Hold-down readjustment
When step 2 is not satisfied, readjustment should be
performed by altering the resistance value of R511 (a
component marked with 8).
G BOARD
VOLTAGE
The following adjustments should always be perform-
ed when replacing IC602
1) Supply 130+200V
former.
2) Input an entirely monoscope signal.
3) Set the PICTURE control and the BRIGHT
controls in to initial reset.
4) Confirm the voltage of A BOARD 0 pin CN651
connecter is less than 116.5V
5) If step 4) is not satisfied, replace IC602 and R637
repeat above steps.
- 2 7
AND READJUSTMENTS
STANDARD
130.0 VDC
100 PA
STANDARD
CONFIRMATION]
or R637.
AC to with variable autotrans-
DC.