AV-20N3

AV-20NMG3

AV-20NMG3B

ADJUSTMENTS

B1 POWER SUPPLY

Item

Measuring

Test point

Ad justment part

 

Description

instrument

 

 

 

 

 

 

 

 

 

 

 

 

Check of

Signal

TP-91 ( B1)

 

1.

Input a whole black signal.

B1 Power

generator

TP-E (#)

 

2.

Connect a DC voltmeter to TP-91(B1) and TP-E (#).

Supply

 

 

 

 

 

3.

Make sure that the voltage is DC116.5±2.0V.

 

DC Volt-

 

 

 

 

 

 

 

 

meter

 

 

 

 

 

 

 

 

 

 

FOCUS ADJUSTMENT

Item

Measuring

Test point

Ad justment part

 

Description

instrument

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ad justment

Signal

 

FOCUS VR

1.

Input a cross-hatch signal.

of FOCUS

generator

 

[In HVT]

2.

While watching the screen, adjust the FOCUS VR to make the

 

 

 

 

 

 

 

 

vertical and horizontal lines as fine and sharp as possible.

 

 

 

 

3.

Make sure that when the screen is darkened, the lines remain in

 

 

 

 

 

good focus.

 

 

 

 

 

 

IF CIRCUIT ADJUSTMENT

Item

Measuring instrument

Test point

Ad justment part

Description

Ad justment

 

Signal

 

 

 

 

 

 

1. VCO

of VCO(CW)

 

generator

 

 

 

 

 

 

 

 

 

 

 

 

 

Remote

 

 

 

 

 

 

 

 

 

 

 

 

 

control unit

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VCO (CW) ***.** MHz

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TOO HIGH

 

 

 

 

 

 

 

 

 

 

 

 

ABOVE REFERENCE

 

 

 

 

 

 

 

 

 

 

 

 

JUST REFERENCE

 

 

 

 

 

YELLOW

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BELOW REFERENCE

 

 

 

 

 

 

 

 

 

 

 

 

TOO LOW

 

 

 

 

 

 

 

 

 

 

 

 

AFT ADJUST

** *(* *)

 

 

 

 

 

 

 

 

 

VCO ADJUST

** *(* *)

 

 

 

 

 

 

 

 

 

FINE

 

 

 

 

 

 

Do no t adjust

 

 

 

DISP : EXIT

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TOO HIGH

ABOVE REFERENCE

J US T R EFE RE NC E

BELOW REFERENCE

Please use signal generator which is correct proof about the sending frequency.

1.Input the PAL full colour bar (210.25MHz) signal.

2.Enter the SERVICE MENU.

3.Select 1.IF from the SERVICE MENU.

4.Press 1 key and select 1.VCO.

5.Select VCO ADJUST with MENU /key.

6.Press MENU -/+ key until the colour of the characters TOO

HIGH changes blue to yellow. Then gradually press the MENU

-/+ key until the TOO LOW changes yellow. At this time, confirm that the value of VCO ADJUST is near +00.

7.Select AFT ADJUST with MENU /key.

8.Press MENU -/+ key until the characters JUST REFERENCE changes blue to yellow.

9.Press the DISPLAY key three times to return to normal screen.

TOO LOW

ADJUSTMENT AT THIS POINT IS USELESS

ADJUSTMENT POINT

20

No. 52025

Page 20
Image 20
JVC AV-20N3/D, AV-20NMG3/-A, AV-20NMG3B service manual Adjustments, B1 Power Supply, Focus Adjustment, If Circuit Adjustment