Trouble Shooting - Mitsubishi Electric 1786FD2 Service Manual

MEA 1786FD2 CRT Monitor Service Guide
Check MCU and OSD for no video output:
Check F12M=12MHz CLOCK,ok?
(1)On the Main Board
(a) IC801 pin18
(b) Y801 pin1
(2)On the Board, IC1901 pin2,3(OSD IC)
DC level = 1~3V ?
(3)IC1901 pin11 ~ pin18 output PWM ?
Check IC801 (BLANK)= "L",ok?
Check IC802 (EEPROM ),ok?
(1) On the Board
(a) SCL ( IC1901 pin 10)
(b) SDA ( IC1901 pin 9)
Check MCU and OSD
for no video output
Start
Use a preset timing
YES
Check +5V, ok ?
(1) On the Main Board,
(a) IC801 pin40
(b) IC802 pin8
(2) On the Video Board,
IC1901 pin6,19
(OSD IC)
YES
YES
Check MCU (IC801)
Reset (pin9) = "H" to "L",ok?
YES
YES
YES
NO
Check +5V power
Check F12M CKT
NO
on the Main Board .
on Main Board,
DC level 1 ~ 3V ?
NO Check
Reset circuit
NO Check
(1) "V-FREQ" circuit
(2) "H-FREQ" circuit
(3) IC801 pin 13,15
NO
Check
(1) pin5 (SDA)
(2) pin6 (SCL)
(3) IC802 data
( EEPROM)
(Brightness, Contrast)

Trouble Shooting

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