MiTAC 7521 PLUS/N service manual 114

7521Plus / N N/B MAINTENANCE

8.4 EXTERNAL MONITOR NO DISPLAY

There is no display or picture abnormal on CRT monitor.

VGA CONTROLLER FAILURE

Replace motherboard or into board-level Troubleshooting.

1.Confirm monitor is good and check the cable are connected properly.

2.Try another known good monitor.

	YES
Display	Replace faulty monitor.
OK?

YES

Check if U24, J506 are cold solder?

NO

Re-soldering.

NO

Remove all the I/O device & cable from motherboard except monitor.

One of the following parts on the mother-board may be defective, use an oscilloscope to check the following signal or replace the parts one at a time and test after each replacement.

Parts:		Signals:
U24	PR15	CRT_IN#
J506	L514	RED
R114	L519	GREEN

YES

Display

OK?

NO

Connect the I/O device & cable to the M/B one at a time to find out which part is causing the problem.

R112	L512	BLUE
C505	L513	HYNC
L518	Q501	VSYNC
L516	Q502	DDCK
L515	R2	DDDA
CA501	R3
CA502

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