Electrical Adjustments; Before Making Electrical Adjustments; Basic Adjustments; Constant Voltage - Toshiba 14af42 Service Manual

1. BEFORE MAKING ELECTRICAL
ADJUSTMENTS
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
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
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 RF.AGC
03 ---
04 H.POSI
05 V.POSI
06 H.SIZE
07 V.SIZE
08 V.CENT
09 V.LIN
10 VS CORR
11 G.DRV
12 B.DRV
13 R.BIAS
14 G.BIAS
15 B.BIAS
16 BRI.CENT
17 SUB CONT
18 CONT.MAX
19 CONT.CENT
20 CONT.MIN

ELECTRICAL ADJUSTMENTS

TV
15
Fig. 1-1
NO. FUNCTION
21 BRI.MAX
22 BRI.MIN
23 COL.MAX
24 COL.CENT
25 COL.MIN
26 TINT
27 SHARPNESS
28 RGB CONTRAST
29 PARABORA
30 TRAPEZIU
31 COR TOP
32 COR BTM
33 V EHT
34 H EHT
35 FM.LVL
36 LEVEL
37 SEP 1
38 SEP 2
39 T.STE
40 X-RAY
88 READ DATA
Fig. 1-2

2. BASIC ADJUSTMENTS

2-1: CONSTANT VOLTAGE

1. Set condition is AV MODE without signal.
2. Connect the digital voltmeter to TP002.
3. Adjust the VR502 until the digital voltmeter is 115 ± 1V.
2-2: RF AGC
1. Place the set with Aging Test for more than 15 minutes.
2. Receive the VHF HIGH (63dB).
3. Connect the digital voltmeter between the pin 5 of
CP101 and the GND.
4. Activate the adjustment mode display of Fig. 1-1 and
press the channel button (02) on the remote control to
select "RF.AGC".
5. Press the VOL. UP/DOWN button on the remote
control until the digital voltmeter is 2.5 ± 0.05V.
2-3: CUT OFF
1. Adjust the unit to the following settings.
G. DRIVE =64, B. DRIVE=64, R. BIAS=64, G. BIAS=64,
B. BIAS=64.
2. Place the set with Aging Test for more than 15 minutes.
3. Activate the adjustment mode display of Fig. 1-1 and
press the channel button (01) on the remote control to
select "CUT OFF".
4. Adjust the Screen Volume until a dim raster is obtained.
2-4: 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 (13) 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.
2-5: FOCUS
1. Receive the monoscope pattern.
2. Turn the Focus Volume fully counterclockwise once.
3. Adjust the Focus Volume until picture is distinct.
2-6: 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 (04) on the remote control to
select "H.POSI".
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.