Mitsubishi Electric 1786FD2 Service Manual page 78

MEA 1786FD2 CRT Monitor Service Guide
Case 2: one or more of R, G, B channel does no display
¡ E Check IC101 pin 18,15,13. If anyone is 0 volt, replace a new IC to IC101.
¡ E Check RGB cathode. If anyone pin is 0 volt, replace a new IC to IC102.
¡ E Check IC102 output path. It must be right and without short circuit.
¡ E Replace CRT if it burns out.
Case 3: OSD does not display on screen
¡ E Check IC101 pin 1,19,20. If they are 0 volt, check IC101 and IC1901.
Case 4: No video display on screen, but OSD can display on screen
¡ E Check IC101 pin 10 (Video Contrast). If it is 0 volt, check IC1901 or maybe IC101 pin 10
short.
Case 5: OSD control cannot adjust Bias
¡ E Check IC1901.
¡ E Check DC restore circuit.
Case6: OSD control cannot adjust Drive
¡ E Check IC101 and IC1901.
Case 7: OSD control cannot adjust Contrast
¡ E Check IC 101 and IC1901.
Case 8: OSD control cannot adjust Brightness
¡ E Check brightness control circuit (G1) and IC801 BRITE output.
Case 9: ABL cannot adjust
¡ E Check ABL circuit.
Case 10: Spot killer function failure
¡ E Check SG101(300KV spark gap). Replace it if it is inserted error.
¡ E check spot killer circuit.
Case 11: Picture quality is not so good
¡ E Check CRT socket. Fix it if it is loose.
¡ E Check IC101 pin 11(clamp gate). If it has no clamping pulse, check H-clamp pulse switch
circuit.
¡ E Replace IC102.
Case 12: Moire appears when Y is greater than 18 Ft-l
¡ E Run auto-alignment procedure to acquire optimum G2 voltage.
¡ E If necessary, decrease G2 voltage.
Case 13: H-blank function failure
Trouble Shooting
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