MiTAC 8355 service manual Audio Drive Failure, Parts Signals

8355 N/B MAINTENANCE

8.15 Audio Failure

Symptom:

No sound from speaker after audio driver is installed.

Audio Drive Failure

1.Check if speaker cables are connected properly.

2. Make sure all the drivers are installed	Board-level
properly.	Troubleshooting

Test	Yes
	Correct it.
OK?

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 parts one at a time and test after each replacement.

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

2.Exchange another known good charger board.

Re-test	Yes
		Correct it.
OK?

Replace

Motherboard

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

Parts:		Signals:
U20	VR1	AOUT_R
U518	C392	AOUT_L
U517	C806	ROUT+
J4	R771	ROUT-
J5	R770	LOUT+
L505	C810	LOUT-
L506	C749	AC97_RST#
L508	R730
L509	R729
C83	R765
C816	R764

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

Parts:	Signals:
U518	MIC1
C762	MIC_INT
L526	MIC_EXT

L85

L25

L527

J18

MIC1

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

Parts: Signals:

U20 CDROM_L

U518 CDROM_R

C771 CDROM_GND

C773 CDROM_LEFT

C772

R738 CDROM_RIGHT

R741 CD_COMM

R739

R773

R740

J530

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