SONY 910101 Service Manual

Service Technical Information

	MODEL NO.
	MINI-SYSTEMS AND RECEIVERS		Bulletin #	91-01-03
	SUBJECT:
	TROUBLESHOOTING GUIDE FOR DEAD SET		Date:	May 17, 2001

START

IS 12VOLT VM

IS DC INPUT

ARE POWER

CHECK BRIDGE

No

No

No

No

PRESENT ON VM

TRANSFORMER

IS FUSE(S) OPEN?

PRESENT?

RECTIFIER

REGULATOR?

WINDINGS OPEN?

Yes

Yes

Yes

Yes

12 VOLT

REPLACE

REPLACE

REGULATOR

TRANSFORMER

FUSE(S)

DEFECTIVE

IS -VFL

-VFL

No

REGULATOR

PRESENT?

DEFECTIVE

Yes

IS VDD

VDD

PRESENT

No

REGULATOR

TO CPU

DEFECTIVE

Yes

WHEN THE HOLD INPUT TO THE CPU IS 'LOW',

ISOLATE THE

IS CPU HOLD

THE POWER CANNOT BE TURNED ON. THIS

HOLD LINE

No

INPUT 'HIGH'?

CONDITION USUALLY OCCURS WHEN ONE OF

FROM THE

MORE POWER AMPS ARE DEFECTIVE.

AMPLIFIERS.

Yes

CHECK AMPLIFIERS.

DOES POWER

CONNECT DUMMY LOADS TO

CHECK

Yes

THE SPEAKER TERMINALS AS

COME ON?

X'TAL

THERE MAY BE DC PRESENT

AT THE OUTPUTS.

No

ARE ALL AMPS ISOLATED?

THE HOLD PRINTED CIRCUIT PATH

(SOME UNITS HAVE SURROUND

Yes

MAY BE SHORTED TO GROUND OR THE

CIRCUIT BOARDS THAT MAY BE

CPU MAY BE SHORTED INTERNALLY.

CAUSING THE TROUBLE).