Hitachi CM771ET, Руководство по обслуживанию

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20
ADJUSTMENTS
1. Power supply
1.1 Standby power supply voltage adjustment.
(1) Turn the switch of the unit off.
(2) Place a jumper wire across R943, Q801 (G)-(S), I101(26pin) to GND, I740(13pin) to GND on main-p.w.b to
disable Main power supply voltage.
(3) Place resister 3.9k (31W) across C971(+) to GND
(4) Receive reverse cross hatch pattern of signal 94A.
(5) Connect a Digital multimeter across C981.
(6) Turn the switch of the unit on.
(7) Adjust Standby power voltage to 6.2
0.05V using R982.
(8) Turn the switch of the unit off.
(9) Remove the jumper wire.
1.2 PFC output voltage adjustment.
(1) Turn the switch of the unit off.
(2) Place a jumper wire across Q801 (G)-(S), I101(26pin) to GND, I740(13pin) to GND on main-p.w.b to disable
horizontal output and E
HV
output.
(3) Place resister 3.9k (31W) across C971(+) to GND
(4) Receive normal cross hatch pattern of signal 94A.
(5) Connect a Digital multimeter b and - of C920.
(6) Turn the switch of the unit on.
(7) Adjust R919 to 364
2V.
(8) Turn the switch of the unit off.
(9) Remove the jumper wire.
1.3 Main power supply voltage adjustment.
(1) Turn the switch of the unit off.
(2) Place a jumper wire across Q801 (G)-(S), I101(26pin) to GND, I740(13pin) to GND on main-p.w.b to disable
horizontal output and E
HV
output.
(3) Place resister 3.9k (31W) across C971(+) to GND
(4) Receive reverse cross hatch pattern of signal 94A.
(5) Connect a Digital multimeter across C972.
(6) Turn the switch of the unit on.
(7) Adjust Main power supply voltage to 85.5
0.3V using R973.
(8) Turn the switch of the unit off.
(9) Remove the jumper wire.