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High Voltage Hold-Down CheckABL Check
When the following parts (the parts to which the mark isWhen the following parts (the parts to which the mark is
attached on the schematic diagram) are replaced, be sure toattached on the schematic diagram) are replaced, be sure to
perform the following checks.perform the following checks.
P board ........ IC509, IC511, D527, R539, R577, R578,P board ........ R1507, R1508, R1509
R579, R580, R592, R588, R587B board........ R1461, R1464, R1467, R1469, R1470,
R1471
1. Turn off the main power.
2. Connect a digital voltmeter between TP505 and TP5141. Turn off the main power.
(GND) of P board.2. Disconnect the CN504 connector from the P board.
3. Connect a 200 kW variable resistor between TP5083. Connect a DC ammeter between pin-1 and pin-3 of
and TP514 (GND) of P board.CN504 on the P board
[Adjust the 200 kW variable resistor to its maximum[Pin-3 is the positive (+) side.]
resistance value.]4. Turn on the main power.
4. Turn on the main power.5. Connect the 1080/60i all white signal (see note) to
5. Connect the 480/60i all black signal (see note) to inputinput connector.
connector.Note: 1125 (1080) entire white signal
Note: NTSC all black signal6. Push the BRIGHTNESS and CONTRAST buttons to
6. Push the BRIGHTNESS and CONTRAST buttons totheir MANUAL positions (to turn the green LEDs on
their MANUAL positions (to turn the green LEDs onthe buttons.)
the buttons.)7. Check to see that ABL operates when the BRIGHT-
7. Set the BRIGHTNESS and CONTRAST buttons toNESS and CONTRAST buttons are turned from their
their MIN positions.MIN positions toward the MAX positions. [Check
8. Confirm that the raster disappears from the CRTthat the maximum value of the DC ammeter reading is
screen when the DC voltage at TP505 reaches thewithin the range as shown below.]
following voltage as the 200 kW variable resistor is0.50 to 0.60 mA
turned to decrease its resistance value gradually.8. Turn off the main power.
4.90 to 5.10 V9. Disconnect the DC ammeter.
9. Turn off the main power.10. Connect CN504 connector to the P board again.
10. Remove the 200 kW variable resistor from TP508.
11. Turn on the main power.[Connection]
12. Confirm that the DC voltage at TP505 is as follows.P board (Side B)
3.95 ? 0.15 V
CBA
13. Connect the 480/60i entire white signal to input connector.
R1505Ammeter
1
14. Set the BRIGHTNESS and CONTRAST buttons to
50kW
their MAXIMUM positions.R15042
15. Confirm that the DC voltage at TP505 is as follows.3
4.25 ? 0.20 V4
16. Disconnect the digital voltmeter.
TP5035
Digital6
[Connection]voltmeter
ABC
P board (Side A)TP505
1
2
3
TP508
4
5200kW
TP514
6
BVM-D9H1U/D9H5U/D9H1E/D9H5E/D9H1A/D9H5A4-3 |
ACEC
SONY
