Electrical Adjustments; Adjustment Procedure; Basic Adjustments - Toshiba 27AF44 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 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 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
17 BRIGHT MIN
18 CONTRAST MAX

ELECTRICAL ADJUSTMENTS

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

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.
Adjust the VR502 until the digital voltmeter is 135 ± 0.5V.
4.
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 to
select 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 PHASE
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. PHAS".
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.
D-1