MiTAC 7521 PLUS/N 7521Plus / N N/B MAINTENANCE, Audio Failure, Board-level, Troubleshooting for

7521Plus / N N/B MAINTENANCE

8.10 AUDIO FAILURE

No sound from speaker after audio driver is installed.

AUDIO DRIVE FAILURE	Board-level
	Troubleshooting for
	audio test error.

1.Check if speaker cables are connected properly.

2.Make sure all the drivers are installed properly.

Check the following parts for cold solder or one of the following parts on the motherboard may be defective,use an oscilloscope to check the following signal or replace the parts one at a time and test after each replacement.

YES	Test
	OK?

NO

1.Try another known good speaker, CD-ROM.

2.Exchange another known good charger board.

YES

End.	Test
	OK?
	NO

Replace M/B or go

into board-level Troubleshooting.

1.If no sound cause of line out, check the following parts & signals:

Parts:	Signals:
U5, C52	AOUT_R
U6, C65	AOUT_L
VR501	ROUT+
C81, C80	ROUT-
C71, C62	LOUT+
R52, R49	LOUT-
R45, R31	SPK_OFF
R64, R61

R34, R33

Charge BD

2.If no sound cause of MIC, check the following parts & signals:

Parts: Signals:

U5, C61 MIC1

L506, L505

C75, J509

J4, L13, L10

R41, R42

C39, R50

D2, U4

3.If no sound cause of CD-ROM,check the following parts & signals:

Parts: Signals:

U5, C63 CDROM_LEFT C73, C64 CDROM_RIGHT

J512 CDROM_GND

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