Yamaha F-20B Service Manual Download

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SERVICE MANUAL

HAMAMATSU, JAPAN

1.507K-033 K

Printed in Japan 2001.08

011592

20010720-17800

CONTENTS

SPECIFICATIONS .............................................................................. 3

PANEL LAYOUT .................................................................................. 3

CIRCUIT BOARD LAYOUT ................................................................. 4

BLOCK DIAGRAM .............................................................................. 4

DISASSEMBLY PROCEDURE ........................................................... 5

CIRCUIT BOARDS ............................................................................. 7

IC BLOCK DIAGRAM .......................................................................... 8

INSPECTIONS .................................................................................... 8

PARTS LIST

OVERALL CIRCUIT DIAGRAM

BASS AMPLIFIER

This document is printed on chlorine free (ECF) paper with soy ink.

Summary of Contents for F-20B

Page 1: ...0010720 17800 CONTENTS SPECIFICATIONS 3 PANEL LAYOUT 3 CIRCUIT BOARD LAYOUT 4 BLOCK DIAGRAM 4 DISASSEMBLY PROCEDURE 5 CIRCUIT BOARDS 7 IC BLOCK DIAGRAM 8 INSPECTIONS 8 PARTS LIST OVERALL CIRCUIT DIAGRAM BASS AMPLIFIER This document is printed on chlorine free ECF paper with soy ink ...

Page 2: ...g disassembly and parts replacement Recheck all work before you apply power to the unit WARNING CHEMICAL CONTENT NOTICE The solder used in the production of this product contains LEAD In addition other electrical electronic and or plastic where applicable components may also contain traces of chemicals found by the California Health and Welfare Agency and possibly other entities to cause cancer an...

Page 3: ...neral model 230V 50Hz Dimensions W x H x D 357 x 453 x 242mm 14 1 x 17 8 x 9 5 Weight 10 5kg 23 lbs 2 oz INPUT PASSIVE ACTIVE Input Level Select Switch VOLUME No sound is produced when the VOLUME knob is set to 0 ACTIVE EQUALIZER TREBLE HIGH MID LOW MID BASS POWER INDICATOR The lamp will light when the amplifier s power switch is ON AUX IN Use the volume control on the audio device to control its ...

Page 4: ...CTIVE TYPE TONE CONTROL POWER SUPPLY CIRCUIT POWER TRANSFORMER 4Ω Speaker PHONE AUX IN CN2 4P CN1 2P CN3 3P CN4 5P CN5 5P POWER SWITCH SW1 T2 T1 T4 T1 T2 G U C S BS MAIN 1 2 MAIN 2 2 T3 GAIN SELECT ACTIVE CH PASSIVE CH BASS VR5 LOW MID VR4 HIGH MID VR3 TREBLE VR2 VR1 IC3 5 7 VOLUME JK3 JK2 JK1 SW2 IC1 IC2 OP AMP OP AMP 8 4 12V 12V B B 5 3 12V 12V 8 4 Top View Side View Front View ...

Page 5: ...marked 30 The pre main unit can then be removed by sliding it backward Fig 1 2 Speaker Time required about 2 min 2 1 Remove the back board See Procedure 1 1 2 2 Pull out the speaker wires Fig 1 2 3 Remove the four 4 screws marked 60a The speaker can then be removed Fig 1 3 MAIN 1 2 Circuit Board Time required about 4 min 3 1 Remove the pre main unit See Procedure 1 3 2 Remove the five 5 knobs mark...

Page 6: ...Transformer Power Transformer Fig 4 P80 P80 MAIN1 2 Circuuit Board MAIN1 2 Circuuit Board MAIN1 2 Circuuit Board MAIN1 2 Circuuit Board Fig 3 4 MAIN 2 2 Circuit Board Time required about 3 min 4 1 Remove the pre main unit See Procedure 1 4 2 Remove the screw marked C80 The MAIN 2 2 circuit board can then be removed Fig 3 Fig 5 5 Power Transformer Time required about 4 min 5 1 Remove the pre main u...

Page 7: ...SW A A INPUT GAIN SELECT VOLUME TREBLE A A MAIN1 2 CIRCUIT BOARD CIRCUIT BOARDS MAIN 1 2 J U C CNA V755470 MAIN 1 2 H B CNA V755480 MAIN 2 2 J U C CNA V755470 MAIN 2 2 H B CNA V755480 MAIN2 2 CIRCUIT BOARD Component side to MAIN 1 2 CN5 VERSION FUSE RATE INDICATION J U 250V 315mAL E BS 250V T160mAL Must be erased Must be erased Component side ...

Page 8: ...t or left makes the sound gradually larger or smaller 3 3 Make sure that rotating the TREBLE knob to the right or left boosts or cuts the high frequency 3 4 Make sure that rotating the HIGH MID knob to the right or left boosts or cuts the upper middle frequency 3 5 Make sure that rotating the LOW MID knob to the right or left boosts or cuts the lower middle frequency 3 6 Make sure that rotating th...

Page 9: ...eral export model 110V H North European model W General export model 220V I Indonesian model N X General export model J Japanese model Y Export model WARNING Components having special characteristics are marked and must be replaced with parts having specifications equal to those originally installed The numbers in QTY shows quantities for each unit The parts with in Part No are not available as sp...

Page 10: ...F 20B 2 OVERALL ASSEMBLY 50 20 10 C40 C60 C50 C60 C50 C30 C30 A C20 C70 C90 C80 40 30 C100 C110 Overall Cabinet Assembly Pre Main Unit 60 60a ...

Page 11: ...ss Head Screw Flat Washer Label Label Label Speaker Unit Bind Head Screw OVERALL CABINET ASSEMBLY Overall Cabinet Assembly Cabinet Assembly Corner Protector Oval Head Screw Handle Handle Holder Oval Head Screw Foot Bind Head Tapping Screw 1 Flat Washer Name Plate Bind Head Tapping Screw 1 Bind Head Tapping Screw 4 0X25 MFZN2BL 4 0X10X0 8 MFZN2BL 4ohm 30W 3 0X12 MFZN2BL KPBO KAH1D 205 KPBO KAH3D400...

Page 12: ...F 20B 4 A10 A70 A60 A40 A10 A30 A80 A90 A20 P60 P40 P60 P30 P75 P70 P50 P10 P20 P90 P80 A50 P100 P120 P110 A100 A110 A130 A140 A120 Amp Kit P77 PRE MAIN UNIT ...

Page 13: ... Pan Head Screw Button Knob Toothed Lock Washer B Earth Mark Amp Kit Amp Kit Amp Kit Amp Kit Circuit Board Circuit Board Insulation Sheet Sleeve Power SW Transformer Transformer Transformer Cord Holder Cord Cord Cord Cord Cord Strain Relief Cord Strain Relief Toothed Lock Washer A Flat Washer Hexagonal Nut Flat Washer Hexagonal Nut PINGOOD LCC 10 4 0X10 MFZN2BL 1 4 0 MFZN2Y 4 0 MFZN2Y 3 0X10 MFZN2...

Page 14: ...ylar Capacitor Mylar Capacitor Electrolytic Cap Electrolytic Cap Capacitor Monolithic Ceramic Cap Monolithic Ceramic Cap Electrolytic Cap Electrolytic Cap Electrolytic Cap Electrolytic Cap Base Post Connector Base Post Connector Base Post Connector Diode Stack Fuse Fuse IC IC IC Phone Jack Phone Jack Phone Jack LED Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon Resistor Car...

Page 15: ...sistor Metal Oxide Film Resistor Metal Oxide Film Resistor Carbon Resistor Carbon Resistor Carbon Resistor Push Switch Rotary Variable Resistor Rotary Variable Resistor Rotary Variable Resistor Rotary Variable Resistor Rotary Variable Resistor Zener Diode Zener Diode Speaker Unit Power SW Transformer Transformer Transformer Cord Cord Cord Cord 3 3K 1 4 J 33 0K 1 4 J 33 0K 1 4 J 100 0K 1 4 J 10 0K ...

Page 16: ... AUX IN PHONES J U C S BS 250V 315mA 250V T160mA L WARNING D2SBA20 VP344100 DIODE STACK 1 5A 200V DB1 GAIN SELECT BASS LOW MID HIGH MID TREBLE VOLUME OP AMP HIFI AMP OP AMP OP AMP OP AMP OP AMP OP AMP OP AMP OP AMP KEC 54238 KEC 54238 Components having special characteristics are marked and must be replaced with parts having specifications equal to those originally installed 4 SPEAKER ...

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