Panasonic TX-25P20T / TX-34P250T / TX-80P250Z Service Manual ▷ View online
5 Adjustments
Item / Preparation
Adjustment Procedure
B Voltage
1.
1.
Operate the TV set.
2.
Set control: (MARKET MODE CHK 2)
Brightness.............min imum
Sub Bright.............minimum
Volume.................min imum
Sub Bright.............minimum
Volume.................min imum
Confirm the indicated test points for the specified voltage:
TPA 140 : 140 ± 0.2V
TPA 12 : 12 ± 1V
TPA 9 : 9 ± 1V
TPA 5 & TPA 32 : 5 ± 1V
TPA 140 : 140 ± 0.2V
TPA 12 : 12 ± 1V
TPA 9 : 9 ± 1V
TPA 5 & TPA 32 : 5 ± 1V
RF AGC
1.
1.
Receive a colour bar pattern.
2.
Set the input level to 63 ± 1dB. (75
Ω
opened).
3.
Connect an oscilloscope to AGC:TPA20 with DC mode.
1.
Set RF AGC Control such as to procedure a snowy picture.
2.
Set RF AGC Control at the point just before the voltage at
AGC:TPA20 begins to drop.
AGC:TPA20 begins to drop.
3.
Increase the input level by 2dB and confirm that the voltage
changes.
changes.
High Voltage
1.
1.
Operate the TV set.
2.
Receive the crosshatch pattern.
3.
Set to 0 Beam.
(Screen Control : min. CONTRAST : min)
(Screen Control : min. CONTRAST : min)
1.
Connect a DC voltage meter to TPD 16 and confirm the +B voltage
is 141.0 ± 2.0V.
is 141.0 ± 2.0V.
2.
Connect a high voltage meter (Electrostatic Type) to an anode of
the picture tube.
the picture tube.
3.
Confirm that the high voltage is within the range of 31.0 ± 0.7 kV.
Sub Contrast
1.
1.
Receive a colour bar pattern.
2.
Connect an oscilloscope to TPA41.
3.
Connect a short jumper between TPA57 & TPA50 FBT pin3 &
TPA32.
TPA32.
4.
Set controls:
Picture menu....................Dyn amic Normal
Picture menu....................Dyn amic Normal
1.
Adjust Bright Control:
a=2.3 ± 0.2 Vp-p
2.
Adjust Sub Contrast Control:
b=2.8 ± 0.1 Vp-p
PAL Colour Output
1.
1.
Receive a PAL colour bar pattern.
2.
Connect an oscilloscope probe to TPA41.
3.
Connect a short jumper between TPA57 & TPA50 FBT pin3 &
TPA32.
TPA32.
4.
Set controls:
Picture menu....................DYN AMIC NORMAL
Picture menu....................DYN AMIC NORMAL
1.
Adjust Bright Control:
a=2.3 ± 0.2 V
2.
Adjust Sub Colour control.
3.
Connect the oscilloscope probe to TPA41.
4.
Connect the waveform:
b=2.2 ± 0.1 Vp-p
NTSC Colour Output
1.
1.
Apply 3.58MHz NTSC Rainbow pattern.
2.
Connect an oscilloscope probe to TPA40.
3.
Connect a short jumper between D11-1 and D11-2 / TPA53 and
TPA54.
TPA54.
4.
Set controls:
Picture menu....................DYN AMIC NORMAL
Picture menu....................DYN AMIC NORMAL
1.
Adjust Bright Control:
a=2.3 ± 0.2 Vp-p
2.
Confirm that the waveform:
b=1.3 ± 0.5Vp-p
9
TX-25P20T
TPA 220 : 220 ± 15V
Colour Purity
1. Set the Brightness and Contrast controls to their maximum
positions.
2. Operate the TV set for over 15 minutes.
3. Fully degauss the picture tube by using an external
degaussing coil by rotating R-B static convergence magnet.
4. Apply a crosshatch pattern signal and adjust the static
convergence magnets roughly.
5. Apply a green pattern signal.
6. Loosen a clamp screw for the deflection yoke and move the
deflection yoke as close to the purity magnet as possible.
7. Adjust the purity magnetic so that a vertical green field is
obtained at the centre of the screen.
Fig. 20
8. Slowly press the deflection yoke and set it where a uniform
green field is obtained.
9. Adjust roughly the Low Light controls and make sure that a
uniform white field is obtained.
10. Tighten the clamp screw.
Convergence
1. Apply a crosshatch pattern signal and set Contrast control
to the maximum position.
2. Adjust Brightness control to obtain a clear pattern.
3. Adjust the Red and Blue line at the centre of the screen.
Fig. 22
4. Adjust Red and Blue with Green line at centre of the screen
by rotating (RB) -G static convergence magnet.
5. Lock convergence magnets with silicone sealer.
6. Remove the DY wedges and slightly tilt the deflection yoke
vertically and horizontally to obtain the good overall
convergence.
convergence.
Fig. 23
7. Fix the deflection yoke by reinserting the DY wedges. Refer
to Fig. 24.
8. If purity error is found, repeat “Colour Purity” adjustment.
Before Colour Purity, Convergence and White Balance adjustments are attempted, V.
Center, V. Height, H. Width, H. Centre and Focus adjustments must be completed.
Center, V. Height, H. Width, H. Centre and Focus adjustments must be completed.
10
TX-25P20T
5.1.1. Preparation
1. Receive a colour bar signal with colour “OFF”, and operate
the TV set for more than 15 minutes.
2. Set the picture menu to “DYNAMIC NORMAL” and the AI to
off.
3. Connect an oscilloscope to TPL7 with DC mode.
4. Set the TV set to Market Mode : white balance adjustment
(CHK 3).
5. Set the data level of SUB BRIGHT, R,G,B-CUT OFF and
R,G,B-DRIV to the table values.
Display
Data Level
R-CUT OFF
63
G-CUT OFF
128
B-CUT OFF
63
R-DRIVE
128
B-DRIVE
128
SUB BRIGHT
63
5.1.2.
Adjustment
1. Select G-CUT OFF adjustment mode and collapse vertical
scan.
2. Adjust G-CUT OFF control to become the DC=0V to video
level at 180 V as shown in Fig. 1.
3. Slowly turn the screen control clockwise until a green colour
horizontal line appears on the picture tube. This is the
setting point for the screen control.
Note that do not adjust the G-CUT OFF setting in the
following procedure.
setting point for the screen control.
Note that do not adjust the G-CUT OFF setting in the
following procedure.
4. Adjust the remained R and B-CUT OFF contyrols so as to
get a white horizontal line on the screen.
5. Return to full SCAN by pushing the position 5 key on the
remote control.
6. Adjust the R-Drive and B-Drive controls as to obtain uniform
white on the white bar of the grey scale pattern.
7. Confirm correct B/W rendition and greyscale tracking or
repeat CUT OFF and drive control set up.
Note : Write down the original value for each address
before adjusting anything.
before adjusting anything.
8. Wedge A shown in Fig. 2 should be fixed within a range of
45 to the left of the vertical line as shown.
9. After inserting wedge A, insert wedges B, C and D. The
wedges should be set 90 degrees apart from each other.
10. Be certain that the four wedges are firmly fixed and the
Deflection Yoke is tightly clamped in place otherwise the
Deflection Yoke may shift its position and cause a loss of
convergence and purity.
Deflection Yoke may shift its position and cause a loss of
convergence and purity.
5.1.3.
Adjustment of Pincushion
1. Receive the crosshatch pattern.
2. Adjust the vertical line to straight line by PARABOLA.
3. Adjust the vertical line to straight line of bothside vertical
line in Fig. 1 by TRAPEZOID.
4. Adjust the corner-pincushion in Fig. 2 by EW-CORNER 1
and EW-CORNER 2.
5.1. White Balance (MARKET MODE CHK 3)
11
TX-25P20T
6 G-BOARD
TNP4G120AK
TX-25P20T
13
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