Yamaha Overall Circuit Diagram, ABCDEFG P.1, 5 F-20B, MAIN 1/2, MAIN 2/2, KEC-54238, Op Amp

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<P.1>

OVERALL CIRCUIT DIAGRAM

GAIN SELECT

OP AMP

D2SBA20 (VP344100) DIODE STACK 1.5A 200V

DB1

INPUT

AUX IN

POWER ON/OFF

OP AMP

J, U, C

S, BS

250V 315mA 250V T160mA L

OP AMP

VOLUME

PHONES

TRANS

FORMER

4 SPEAKER

Note: See parts list for details of circuit board component parts.

F-20B

KEC-54238

WARNING

Components having special characteristics are marked and must be replaced with parts having specifications equal to those originally installed.

F-20B

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Contents CONTENTS BASS AMPLIFIERF-20B WARNING CHEMICAL CONTENT NOTICEIMPORTANT NOTICE IMPORTANT NOTICE FOR THE UNITED KINGDOMPANEL LAYOUT SPECIFICATIONSF-20B BLOCK DIAGRAM CIRCUIT BOARD LAYOUTPOWER AMP POWER TRANSFORMERDISASSEMBLY PROCEDURE 1.Pre-MainUnit Time required about 2 min2.Speaker Time required about 2 min F-20BF-20B 4.MAIN 2/2 Circuit Board 5.Power Transformer Time required about 4 minTime required about 3 min CIRCUIT BOARDS F-20BIC BLOCK DIAGRAM 2.Power supply3.Inspection procedure INSPECTIONSCONTENS PARTS LISTBASS AMPLIFIER F-20BOVERALL ASSEMBLY 10 Overall Cabinet AssemblyF-20B 20 Pre-MainUnitF-20B DESCRIPTIONREMARKS New partsPRE-MAINUNIT F-20B V 6 9 5 4 8 0 0 ChassisELECTRICAL PARTS F-20BF-20B HF456330OVERALL CIRCUIT DIAGRAM ABCDEFG P.1F-20B 5 F-20B