Sherwood RX-4109 User Manual download pdf (Page 8)

Symptom

Power On Failure. A) AC-Cord check.

1. FLT does not light up. B) Power Trans ( Main/ST-BY ) check.

2. ST-BY LED does not light up. C) Fuse's disconnection check. FUSE (101 )

D) Connector's disconnection or disjuction.

Change or close insertion of the connector. CP ( 503 )

E) Inferior Stany-By switch. SW ( SW402 )

F) µ-COM I.C check.

1. µ-COM IC B+( 5 )V check. IC301 Pin No. ( 12 )

Fuse Disconnection. A) Inferior transformer.

(Power On) B) AMP Drive Transistor out ( POWER TR ) Q ( 306L/R, 307L/R )

C) AMP Drive I.C out ( POWER TR ) Q ( 305L/R )

Key Disorder. A) KEY's being pushed check. SW ( 400 ~ 417 )

B) KEY data check. IC301 Pin No.( 29, 30 )

C) µ-COM I.C inferior. IC301

1. µ-COM IC B+( 5.5 )V check IC301 Pin No. ( 12 )

Power Off in 2~3 sec. A) Drive I.C out ( POWER TR ) Q ( 306L/R, 307L/R )

after Power On. B) Drive Transistor out ( POWER TR ) Q ( 305L/R )

C) Protection circuit check.

1. Output DC check. R ( 537, 532 )

2. µ-COM I.C protection terminal check. I.C301 Pin No. ( 1 )

Bump Sound. A) POWER MUTE transistor's out and inferior. Q ( 315, 314L/R )

( During Input-Select Switch's change. ) µ-Com Front Mute Control PORT check. IC301 Pin No. ( 15 )

Sounds from Speaker. A) HEADPHONE JACK connection inferior. JACK ( 301 )

when Headphone's connected . B) DRIVER I.C inferior.

1. µ-Com H/P IN/OUT control "PORT"check. IC400 Pin No. (3 )

Bass Control Failure. A) TONE VOLUME IC check. IC601

Treble Control Failure. 1. Signal IN/OUT terminal. I.C Pin No. ( 7, 31 )

2. IC voltage check ( +10 )V I.C Pin No. ( 35 )

3. IC control data check. I.C Pin No. ( 1, 2, 36 )

AMP Sound dead. A) Signal Mute TR's inferior. Q ( 319, 314L/R )

1. L / R Channel dead. B) Connector disconnection & disjunction. FPC ( 101 )

2. LEFT Channel dead. Changer or close insertion of the connector.

3. RIGHT Channel dead. C) Speaker wire's disjuction.

Close insertion of the speaker wire.

D) Signal switching IC check. I.C ( 601 )

1. IC voltage check ( +10 )V I.C Pin No. ( 35 )

2. Switching IC control data check. I.C Pin No. ( 1, 2, 36 )

3. Switching IC signal IN/OUT check. I.C Pin No. ( 7, 31 )

Cause and Remedy

TROUBLESHOOTING

Ref NO.

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Sherwood RX-4109 User Manual Page 8