Sony KV-21SE43C, KV-20S90 service manual Safety Related Adjustments, HOLD-DOWN Readjustment

KV-20S90 / 21SE43C

SECTION 3: SAFETY RELATED ADJUSTMENTS

3-1. X R582 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, C511, C574, C575, D572,			HV HOLD-DOWN
D573, D574, R582, R583, R584,			R582
R585, R586, R578, R625, R626,
R640, R635,T504, IC301, IC521,
IC602	A Board

HOLD-DOWN READJUSTMENT

If the setting indicated in Step 2 of Hold-Down Operation Confirmation cannot be met, readjustment should be performed by altering the resistance value of R582 component marked with X.

T504

FBT

ampmeter 3.0 mA DC range

ABL + A -

IABL

PREPARATION BEFORE CONFIRMATION

1.Turn the POWER switch ON. Input a white signal and set the PICTURE and BRIGHTNESS controls to maximum.

2.Confi rm that the voltage between C574 (+) and ground is more than 99.8 VDC when set is operating normally with 120 +/- 2 VAC.

HOLD-DOWN OPERATION CONFIRMATION

1.Connect the current meter between Pin 11 of the FBT (T504) 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 = 95 + 100/-95µA.

3.Confi rm the voltage of A Board TP-600 is 117 ± 0.3 VDC.

4.Connect the digital voltmeter and the DC power supply via Diode 1SS119 to C574 (+) 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: less than or equal to 127.3 VDC).

8.Input a white signal and set PICTURE and BRIGHTNESS to maximum: (standard: less than or equal to 127.3 VDC).

9.Repeat steps 4 to 7.

3-2. B+ VOLTAGE CONFIRMATION AND ADJUSTMENT

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: IC001,IC602, R030, R625, R626,

R632, R633, R635, R636, R637, R638, R639

1.Supply 130 +2.0 / -0.0V to the set with a variable auto transformer.

2.Input a dot signal.

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

4.Set to Service Adjustment Mode.

5.Select PADJ with 1 and 4 .

6.Adjust with 6 to the 0 level.

7.Confi rm the voltage of A Board TP-600 is <125 VDC.

8.If step 7 is not satisfi ed, replace the components listed above, then repeat the above steps.

9.Supply 130 +2.0 / -0.0V to the set with a variable auto transformer.

10.Adjust with 3 and 6 for 117.0 ± 0.3 VDC.

11.Press MUTING then ENTER to save into the memory.

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