Service Adjustments; Electrical Adjustments; Basic Adjustments; Adjustment Procedure - JVC AV-14F704 Service Manual

AV-14F704

SERVICE ADJUSTMENTS

1. ADJUSTMENT PROCEDURE

Read and perform these adjustments when repairing the circuits or
replacing electrical parts or PCB assemblies.
CAUTION
• Use an isolation transformer when performing any service on this
chassis.
• Before removing the anode cap, discharge electricity because it
contains high voltage.
• When removing a PCB or related component, after unfastening
or changing a wire, be sure to put the wire back in its original
position.
• When you exchange IC and Transistor for a heat sink, apply the
silicon grease on the contact section of the heat sink. Before
applying new silicon grease, remove all the old silicon grease.
(Old grease may cause damages to the IC and Transistor.)
Prepare the following measurement tools for electrical
adjustments.
1. Oscilloscope
2. Digital Voltmeter
3. Multi-Sound Signal Generator
4. Pattern Generator
On-Screen Display Adjustment
1. In the condition of NO indication on the screen.
Press the VOL. DOWN button on the set and the Channel button
(9) on the remote control for more than 1 second to appear the
adjustment mode on the screen as shown in Fig. 1-1.
00 OSD
3. Use the Channel UP/DOWN button or Channel button (0-9) on
the remote control to select the options shown in Fig. 1-2.
4. Press the MENU button on the remote control to end the
adjustments.
NO. FUNCTION
00 OSD H
01 CUT OFF
02 H. VCO
03 H. PHASE
04 AFC GAIN
05 V. SHIFT
06 H. SIZE
07 V. SIZE
08 V. LINEARITY
09 VS CORRECTION
10 DRIVE R
11 DRIVE B
12 R CUT OFF
13 G CUT OFF
14 B CUT OFF
15 BRIGHT MAX
16 BRIGHT CENT
BRIGHT MIN
17
8

ELECTRICAL ADJUSTMENTS

TV
35
Fig. 1-1
NO. FUNCTION
18 CONTRAST MAX
19 CONTRAST CENT
20 CONTRAST MIN
21 COLOR MAX
22 COLOR CENT
23 COLOR MIN
24 TINT
25 SHARPNESS
26 Cb DELAY FINE
27 Cr DELAY FINE
28 Cb PEDESTAL ADJ
29 Cr PEDESTAL ADJ
E/W PARABOLA
30
31 E/W CORNER
32 E/W TRAPEZIUM
33 LEVEL
34 SEPARATION1
SEPARATION2
35
Fig. 1-2
No. 52130

2. BASIC ADJUSTMENTS

2-1: CONSTANT VOLTAGE
1. Place the set with Aging Test for more than 5 minutes.
2. Set condition is AV MODE without signal.
3. Connect the digital voltmeter to the TP003.
4. Adjust the VR502 until the DC voltage is 115 ± 1V.
2-2: CUT OFF
1. Place the set with Aging Test for more than 15 minutes.
2. Activate the adjustment mode display of Fig. 1-1 and press the
channel button (01) on the remote control to select "CUT OFF".
3. Adjust the Screen Volume until a dim raster is obtained.
2-3: WHITE BALANCE
NOTE: Adjust after performing CUT OFF adjustment.
1. Place the set with Aging Test for more than 10 minutes.
2. Receive the gray scale pattern from the Pattern Generator.
3. Using the remote control, set the brightness and contrast to
normal position.
4. Activate the adjustment mode display of Fig. 1-1 and press the
channel button (12) on the remote control to select "R. BIAS".
5. Press the CH. UP/DOWN button on the remote control toselect
the "R. BIAS", "G. BIAS", "B. BIAS", "B. DRIVE" or "G. DRIVE".
6. Adjust the VOL. UP/DOWN button on the remote control to
whiten the R. BIAS, G. BIAS, B. BIAS, B. DRIVE, and G. DRIVE
at each step tone sections equally.
7. Perform the above adjustments 5 and 6 until the white color is
looked like a white.
2-4: FOCUS
1. Receive the monoscope pattern.
2. Turn the Focus Volume fully counterclockwise once.
3. Adjust the Focus Volume until picture is distinct.
2-5: HORIZONTAL POSITION
1. Receive the monoscope pattern.
2. Using the remote control, set the brightness and contrast to
normal position.
3. Activate the adjustment mode display of Fig. 1-1 and press the
channel button (03) on the remote control to select "H.PHASE".
4. Press the VOL. UP/DOWN button on the remote control until the
SHIFT quantity of the OVER SCAN on right and left becomes
minimum.
2-6: VERTICAL POSITION
1. Receive the monoscope pattern.
2. Using the remote control, set the brightness and contrast to
normal position.
3. Adjust the VR401 until the horizontal line becomes fit to the
notch of the shadow mask.