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Sdbgds101 05 Trouble Shooting Guide No Light - Skipper

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Service data bulletin Instrument: GDS101 Date: 29.05.2008 Created by: Geir Theodorsen SUBJECT:TROUBLE SHOOTING GUIDE NO LIGHT ON SCREEN This trouble shooting guide may be used if some picture is visible on screen but no backlight makes it impossible to see. Before proceeding: Please make shure that this problem is not related to brightness being set to 0 Refer to Data Bulletin “SDB_Gen_01 Screen dead” Contents Check Power to the backlight. 2 Check LED402 2 Measure 12/24V from Terminal board to I/O board Keyboard versionB. Monochrome screens �� � Keyboard version D. Colour screen �� � ��� 2 3 4 � �� �� ��� �� �� �� �� � � �� �� Check Power to the backlight. Check LED402 If one or more LED’s does not light: Then Terminal board is most probably defective. LD300 LD300 LD400 LD401 LD402 Tranceiver Board Operation +5V +12V +24V +48V LD400 LD401 LD402 LD403 LD400: LD401: LD402: LD403: LD403 J105 +5V +12V +24V to backlight with monocrom screen +12V to backlight with colour screen. +48V I/O Board Terminal Board CN1 Measure 12/24V from Terminal board to I/O board The 12/24V from terminal board is the power to backlight inverter. Monochrome screens have 24V CPU Board Colour screens have 12V CN2 CN4 LED1 LED1 CPU Board Power Fig. 4.6 Function LED´s, Terminal, I/O and CPU Boards. Power Indication and function LED´s. The following LED´s are located on the Terminal Board: LD400 LD401 LD402 LD403 +5V +12V +24V +48V The following function LED is located on the I/O Board: LD300 Transceiver board operation There is one function LED on the CPU board LED1 CPU board power Fig. 4.6 indicates position of these LED´s. 43 20001123sw503 The 12/24V is fed through the I/O board to the keyboard. Keyboard versionB. Monochrome screens 24v is used: To inverter produsing high voltage (1500V AC)to screen. It is difficult to measure the high voltage. 24V (with full dimmer) may be measured between the “VIN” pin and chassis. To contrast.(J204) -18 to -21V between chassis and pin. If all voltages are OK then inverter board or backlight is defective. The backlight inverter is a part of Keyboard verB. Part number PK-G001. The baklight is not available for mono screens. New screen required. See Data bulletin “SDBGDS101_02 Guide to change monochrome screen”. SHARP: Part number KY-G001. HITACHI: Part number KY-G002. Keyboard version D. Colour screen