8525 DISPLAY IMAGE ROLL

SYMPTOM: LOSS OF HORIZONTAL AND/OR VERTICAL SYNCRONIZATION (SYNC)
ON 8525 COLOR DISPLAYS.
LOSS OF SYNC MEANS THAT THE DISPLAY IMAGE WILL APPEAR TO "ROLL"
HORIZONTALLY OR VERTICALLY.

PROBLEM ISOLATION AIDS:
THE FOLLOWING VOLTAGE MEASUREMENTS CAN IDENTIFY FAILING FRU'S.

FIX:
THE FOLLOWING TEST PROCEDURE WILL HELP TO IDENTIFY FAILING
FRU'S FOR A ROLLING SCREEN CONDITION.
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-- TEST PROCEDURE --

1) WITH THE POWER SWITCH OFF REMOVE THE AC LINE CORD FROM
THE WALL OUTLET AND THEN FROM THE 8525. OPEN THE SYSTEM UNIT
AND UNPLUG VIDEO CONNECTOR (J4) FROM SYSTEM BOARD. LEAVE THE
SYSTEM UNIT OPEN AT THIS TIME.

2) PLUG THE AC LINE CORD INTO 8525 AND THE WALL OUTLET.
TURN THE 8525 POWER SWITCH ON. ENSURE THAT THE POWER IS
ON BY LISTENING TO THE FAN.
.
.
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TEST PROCEDURES CONTINUE ON NEXT SCREEN
.
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.
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3) LOCATE PIN 9 (HORIZONTAL SYNC) AND PIN 11 (VERTICAL SYNC)
ON THE CABLE END OF THE VIDEO CONNECTOR (J4).
_____________
| | CABLE END OF VIDEO CONNECTOR
| 2 1 |
| 4 3 |
| 6 5 __
| 8 7 __|
| 10 9 |
| 12 11 |
| 14 13 |
|_____________|

4) WITH A DIGITAL VOLTMETER, MEASURE THE VOLTAGE BETWEEN PIN 9
AND GROUND, AND THEN BETWEEN PIN 11 AND GROUND (PINS 7 AND
8 ARE GROUND) AND RECORD VOLTAGES.

5) THE VOLTAGE MEASUREMENTS SHOULD BE BETWEEN 4.9 AND 5.2 VOLTS
DC, BUT MORE IMPORTANTLY, BOTH SHOULD BE THE SAME VALUE
(WITHIN .1 VOLT OF EACH OTHER).

6) IF THE VOLTAGES MEASUREMENTS ARE WITHIN TOLERANCE, THE SYSTEM
BOARD SHOULD BE REPLACED.

7) IF THE VOLTAGE MEASUREMENTS ARE NOT WITHIN TOLERANCE, THE
DISPLAY SHOULD BE REPLACED. IF THE SCREEN CONTINUES TO ROLL
AFTER REPLACING THE DISPLAY, THEN THE SYSTEM BOARD HAS BEEN
DAMAGED AND SHOULD ALSO BE REPLACED.

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