MiTAC 7521 PLUS/N service manual 112

7521Plus / N N/B MAINTENANCE

8.3 VGA CONTROLLER FAILURE LCD NO DISPLAY

There is no display or picture abnormal on LCD.

VGA CONTROLLER FAILURE

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

2.Try another known good monitor or LCD module.

Replace motherboard or into board-level Troubleshooting.

YES

Check if

U24, U2, J1, J2

Re-soldering.

YES

Display

OK?

NO

Replace faulty LCD or monitor.

are cold solder?

NO

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.

Remove all the I/O device & cable from motherboard except LCD panel or extended monitor.

Parts:		Signals:
U24 U2	FA8 FA9	R[2~7]301	TXCLKOUT-

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.

J1	J2	FA11	FA10	G[2~7]301	TXCLKOUT+
Q2	Q3	FA6	FA7	B[2~7]301	TXOUT0-
Q4	Q15	RP11	RP12	VBHSYNC	TXOUT0+
Q14	U14	RP31	RP33	VBVSYNC	TXOUT1-
SW1	R5	RP24	RP32	VBBLANK#	TXOUT1+
R7	R150	RP26	RP36	VGCLK	TXOUT2-
L9	R18	L540	R527	FPVCC	TXOUT2+
R149	L537			LID_OPEN#
L536	L534

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