Electrical Adjustments; Adjustment Procedure; Basic Adjustments - Toshiba 20AF45 Service Manual

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 with a heat sink,
•
apply silicon grease on the contact section of the heat
sink. Befor 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 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 2
seconds to appear the adjustment mode on the screen
as shown in Fig. 1-1.
00 OSD
2. Use the Channel UP/DOWN button or Channel button
(0-9) on the remote control to select the options shown
in Fig. 1-2.
3. 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. LINERITY
09 VS CORRECTION
10 R DRIVE
11 B DRIVE
12 R BIAS
13 G BIAS
14 B BIAS
15 BRIGHT MAX
16 BRIGHT CENT
17 BRIGHT MIN

ELECTRICAL ADJUSTMENTS

TV
29
Fig. 1-1
NO. FUNCTION
18 CONTRAST MAX
19 CONTRAST CENT
20 CONTRAST MIN
21 COLOR MAX
22 COLOR CENTER
23 COLOR MIN
24 TINT
25 SHARPNESS
26 CB DL
27 CR DL
28 CB PED
29 CR PED
30 PARABOLA
31 CORNER
32 TRAPWZIUM
33 LEVEL
34 SEPARATION1
35 SEPARATION2
Fig. 1-2

2. BASIC ADJUSTMENTS

2-1: CONSTANT VOLTAGE
1. Place the set in AV MODE without signal.
2. Connect the digital voltmeter to the TP003.
Adjust the VR502 until the digital voltmeter is 113 ± 0.5V.
3.
2-2: CUT OFF
1. Place the set in Aging Test for more than 15 minutes.
2. Set condition is AV MODE without signal.
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 (01) on the remote control to
select "CUT OFF".
5. Adjust the Screen Volume until a dim raster is obtained.
2-3: WHITE BALANCE, WHITE BALANCE CS
NOTE: Adjust after performing CUT OFF adjustment.
1. Place the set in Aging Test for more than 15 minutes.
2. Receive the gray scale pattern from the Pattern Generator
with Brust On.
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 to
select the "R. BIAS", "G. BIAS", "B. BIAS", "B. DRIVE" or
"R. DRIVE".
6. Adjust the VOL. UP/DOWN button on the remote control
to whiten the R. BIAS, G. BIAS, B. BIAS, B. DRIVE and
R. DRIVE at each step tone sections equally.
7. Perform the above adjustments 5 and 6 until the white
color is looked like a white.
8. Press the TV/VIDEO button on the remote control to set
to the CS mode.
9. Receive the gray scale pattern from the Pattern Generat
or with Brust On.
10. If the picture is too much green.Activate the adjustment
mode display of Fig. 1-1 and press the channel button
(28) on the remote control to select "CB PED".
11. Adjust the VOL. UP/DOWN button on the remote control
to select the step up.
12. If the picture is too much red.Activate the adjustment mode
display of Fig. 1-1 and press the channel button
(29) on the remote control to select "CR PED".
13. Adjust the VOL. UP/DOWN button on the remote control
to select the step down.
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.
D-1
20AF45/20AF45C