Electrical Adjustments; Adjustment Procedure; Basic Adjustments - Toshiba 27DF47 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. 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 2 seconds
to appear the adjustment mode on the screen as shown in
Fig. 1-1.
00 OSD H
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.
4. To display the adjustment screen for TV-A, TV-D, AV
and YUV mode, press the INPUT button on the remote
control. Press the VOL.DOWN button on the set and
the channel (9) on the remote control for more than 2
seconds.

ELECTRICAL ADJUSTMENTS

TV-A
4:3
20
Fig. 1-1
NO. FUNCTION
00 OSD H
01 OSD C
02 CUT OFF
03 H.POSI
04 H BLK L
05 H BLK R
06 V. SIZE
07 V. POSI
08 V. LIN
09 VS CORR
10 V COMP
11 R.BIAS
12 G.BIAS
13 B.BIAS
14 R.DRV
15 G.DRV
16 B.DRV
29 BRI.CENT
30 BRI.MAX
31 BRI.MIN

2. BASIC ADJUSTMENTS

2-1: CONSTANT VOLTAGE
1. Place the set in AV MODE without signal.
2. Connect the digital voltmeter to the TP003.
3. Adjust the VR502 until the digital voltmeter is 130 ± 0.5V.
2-2: CUT OFF
1. Place the set in Aging Test for more than 15 minutes.
2. Place the set in 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 (02) on the remote control to
select "CUT OFF".
5. 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 in Aging Test for more than 15 minutes.
2. Receive the white 100% signal from the Pattern
Generator.
3. Using the adjustment control, set the brightness and
contrast to normal position.
4. Activate the adjustment mode display of Fig. 1-1 and
press the channel button (11) on the remote control to
select "R.BIAS".
5. Using the VOL. UP/DOWN button on the remote control,
adjust the R.BIAS.
6. Press the CH. UP/DOWN button on the remote control to
select the "R.DRIVE", "B.DRIVE", "G.BIAS" or "B.BIAS".
7. Using the VOL. UP/DOWN button on the remote control,
adjust the R.DRIVE, B.DRIVE, G.BIAS or B.BIAS.
8. Perform the above adjustments 6 and 7 until the white
color is achieved.
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
NO.
FUNCTION
32 CONT.CENT
33
CONT.MAX
34 CONT.MIN
35 COL.CENT
36
COL.MAX
37 COL.MIN
38
TINT CENT
39 SHARP.CENT
40
SHARP.MAX
41 SHARP.MIN
42 SUB BIAS
43
H.SIZE
44 PARABOLA
45
TRAPEZIUM
46 COR TOP
47
COR BTM
48 TEST STEREO
49 X-RAY
Fig. 1-2