Video Board - Mitsubishi Electric 1786FD2 Service Manual

MEA 1786FD2 CRT Monitor Service Guide
Check OSD,MCU for no OSD window:
Check +5V, ok?
(1) IC1901(OSD IC) pin,6,19
Check IC1901(OSD IC) pin7(HBNK)&
pin28(V+), ok?
Check SCL, SDA INPUT, ok?

2.Video board

Caution: Before power on, you must check whether all connectors and components of the set are correct, otherwise it maybe to
destroy the set. There assume that following cases depend on above setup OK. Please follow as below and check it step by step.
Case 1:No video display on screen
¡ E Check IC101 pin 10 (Video Contrast). If it is 0 volt, check IC1901 or maybe IC101 pin 10 short.
¡ E Check IC101 pin 18,15,13 If they are 0 volts, 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 Check G1 voltage. If it is lower equal than -182 volts, check spot killer circuit and check IC801
pin6(Blank).
¡ E Check CRT heater. If it is dark, check +8v supply voltage of heater.
¡ E Replace CRT if it burns out.
Check OSD, MCU
for no OSD window
Start
YES
YES
Trouble Shooting
Check +5V power
NO
Check Gnd & +5V
and the R,C CKT
NO
Check HBNK & V+
NO Check R1906 &
R1907
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