Adjustments, B1 power supply, Focus adjustment – JVC AV-20NMG3 EN User Manual

Page 20: If circuit adjustment

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No. 52025

AV-20N3

AV-20NMG3

AV-20NMG3B

20

ADJUSTMENTS

B1 POWER SUPPLY

Item

Measuring

instrument

Test point

Ad justment part

Description

Check of
B1 Power
Supply

Signal
generator

DC Volt-
meter

TP-91 ( B1)
TP-E (
#

#

#

#

)

1. Input a whole black signal.
2. Connect a DC voltmeter to TP-91(B1) and TP-E (#).
3. Make sure that the voltage is DC116.5±2.0V.

FOCUS ADJUSTMENT

Item

Measuring

instrument

Test point

Ad justment part

Description

Ad justment
of FOCUS

Signal
generator

FOCUS VR
[In HVT]

1. Input a cross-hatch s ignal.
2. While watching the s creen, 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

Please us e s ignal generator which is correct proof about the
sending frequency.

Ad justment
of VCO(CW)

Signal
generator

Remote
control unit

1. VCO

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 s elect 1.VCO.
5. Select VCO ADJUST with MENU ▲/▼ key.
6. Press MENU -/+ k ey until the colour of the c haracters 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.

VCO (CW) ***.** MHz

TOO HIGH
ABOVE REFERENCE
JUST REFERENCE

BELOW REFERENCE
TOO LOW
AFT ADJUST

** *(* *)

** *(* *)

** *(* *)

** *(* *)

VCO ADJUST

** *(* *)

** *(* *)

** *(* *)

** *(* *)

FINE

DISP : EXIT

YELLOW

Do no t adjust

ADJUST MENT AT T HIS POINT IS USELESS

ABOVE REFERENCE

TOO HIGH

BELOW REFERENCE

J US T R EFE RE NC E

TOO LOW

ADJUST MENT POINT

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