Sony KV-27V40 service manual Section Safety Related Adjustments, Preparation before Confirmation

KV-27V40 / 27V45 / 27V65 / 29VL40 / 29VL65A / 29VL65C / 29VL85 / 29VL95

SECTION 4

SAFETY RELATED ADJUSTMENTS

ABOARD

R584 CONFIRMATION METHOD (HV HOLD-DOWN CONFIRMATION) AND READJUSTMENTS

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

IC301,IC521,IC603, DY, D573, D574 C505, C507, C508, C509, C511, C515, C520, C572, C573, C574, C575, L591, L501, R582, R583, R585, R586, R578, R579, T504 (FBT)

1.Preparation before Confirmation

Using Variac, apply AC input voltage: 120+2VAC

(or 220 + 2 VAC for KV-29VL65A/29VL65C ONLY)

1)Turn the POWER switch ON.

2)Input a white signal and set the PICTURE and BRIGHT controls to maximum.

3)Confirm that the voltage between C574 (+) or TP503 and ground is more than: 105VDC.

2.Hold-down Operation Confirmation

1)Connect the current meter between Pin 11 of the FBT

(T504) and the PCB land where Pin 11 would normally attach. (see figure 1.0 on next page)

2)Input a dot signal and set PICTURE and BRIGHTNESS to minimum: IABL = 100+100μA

3)Confirm the voltage of A board TP-600 is 135 ± 3VDC

3.Hold-down Readjustment

If the current setting indicated in step 2-2 cannot be met, readjustment should be performed by altering the resistance value of R584, a component marked with .

	T504
	FBT
ammeter
3.0 mA DC
range
ABL	+ A	-

I ABL

B+ VOLTAGE CONFIRMATION AND ADJUSTMENT

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

IC603, IC601, R699

4)Connect the Digital Voltmeter and the DC power supply via diode 1SS119 to C574 (+). (See figure 1.0 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:	141.3 VDC

8)Input a white signal and set PICTURE and BRIGHTNESS to maximum: IABL = 1750+100μA

9)Repeat steps from (4) to (7).

STANDARD
Less than or equal to:	141.3 VDC

1)Using Variac, apply AC input voltage: 130 + 2.0 VAC (or 220.0 ± 2.0 VAC for KV-29VL65A/29VL65C only).

2)Input a dot signal.

3)Set the PICTURE control and the BRIGHT control to minimum.

4)Set to service adjustment mode.

5)Select PADJ with and .

6)Adjust with to the 0 level.

7)Confirm the voltage of A BOARD TP-600 is less than 138 VDC.

8)If step 7 is not satisfied, replace the components, repeat the above steps.

9)Adjust with and for: 135 ± 3 VDC

10)Write into the memory by pressing then

.

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