Yamaha F-20B Ic Block Diagram, Inspections, Preparation, Power supply, Inspection procedure

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 IC BLOCK DIAGRAM

F-20B

 BA4558 (XO078A00) Dual Operational Amplifier IC BLOCK DIAGRAM

 INSPECTIONS BA4558 (XO078A00) Dual Operational Amplifier

MAIN: IC1,IC2,IC3

Output A

1

 

 

 

 

Inverting

2

 

 

 

 

Input A

 

 

-

 

 

Non-Inverting

3

 

 

 

 

 

 

 

 

Input A

 

 

 

 

 

 

 

 

 

-DC Voltage Supply

4

-V

+

 

+V 8

+DC Voltage

 

Supply

 

 

 

7

Output B

+ -

6

Inverting

Input B

 

5Non-Inverting Input B

1.Preparation INSPECTIONS

1.Preparation

To inspect the main unit, the following jigs are required.

CD player Headphones

Before turning the power on, set all the knobs on the panel to "0".

Raise the Input Level Select Switch to select [PASSIVE] position.

2.Power supply

Connect the power cord to the suitable power supply socket for each version.

(UC-120V, E&BS-220V)

3.Inspection procedure

3-1 Input the audio signal of CD player to the [AUX IN] jack.

3-2 Make sure that rotating the [VOLUME] knob to the right (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 the [BASS] knob to the right (or left) boosts (or cuts) the low frequency.

3-7 Make sure that the sound becomes smaller when you depress the Input Level Select Switch to select [ACTIVE] position.

3-8 Raise the Input Level Select Switch again to select [PASSIVE] position. Make sure that the audio signal sounds over the speaker.

3-9 Connect the headphones to the [PHONES] jack. Make sure that the speaker produces no sound and the audio signal sounds over the headphones.

3-10 Set all the knobs on the panel to "0" and finish the inspection.

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Contents CONTENTS BASS AMPLIFIERF-20B WARNING CHEMICAL CONTENT NOTICEIMPORTANT NOTICE IMPORTANT NOTICE FOR THE UNITED KINGDOMF-20B SPECIFICATIONSPANEL LAYOUT BLOCK DIAGRAM CIRCUIT BOARD LAYOUTPOWER AMP POWER TRANSFORMERDISASSEMBLY PROCEDURE 1.Pre-MainUnit Time required about 2 min2.Speaker Time required about 2 min F-20BTime required about 3 min 5.Power Transformer Time required about 4 minF-20B 4.MAIN 2/2 Circuit Board 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