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Model
28HW-53 (serv.man4)
Pages
10
Size
172.8 KB
Type
PDF
Document
Service Manual
Brand
Device
TV / CTR / Part 1 - Text (1-10)
File
28hw-53-sm4.pdf
Date

Sharp 28HW-53 (serv.man4) Service Manual ▷ View online

7
28HW-53H
barrel shape.
• When the volume down button is pressed, side pincushion changes from pincushion to
barrel shape.
• Press the stand-by button on the remote control to store.
Corner Symmetry
Adjust the Corner Symmetry so that the picture is centred.
The effect of this adjustment is shown in figure 7.
Note: This adjustment affects to upper and lower sides.
•  When the volume up button is pressed, side pincushion changes from pincushion to
barrel shape.
• When the volume down button is pressed, side pincushion changes from pincushion to
barrel shape.
• Press the stand-by button on the remote control to store.
Vertical Linearity
Adjust the Vertical Linearity so that the upper and lower parts of the picture are symmetrical.
The effect of this adjustment is shown in figure 8.
• When the volume up button is pressed, the upper picture scanning decreases and the
lower picture scanning increases.
• When the volume down button is pressed, the upper picture scanning increases and the
lower picture scanning decreases.
• Press the stand-by button on the remote control to store.
Vertical Angle
Adjust the Vertical Angle so that the picture is centred.
The effect of this adjustment is shown in figure 9.
•  When the volume up button is pressed, side pincushion changes, specially the lower
picture.
• When the volume down button is pressed, side pincushion changes, specially the lower
picture.
• Press the stand-by button on the remote control to store.
Vertical Bow
Adjust the Vertical Amplitude so that the picture is centred.
The effect of this adjustment is shown in figure 10.
•  When the volume up button is pressed, side pincushion changes from pincushion to
barrel shape, specially the lower picture.
• When the volume down button is pressed, side pincushion changes from pincushion to
barrel shape, specially the lower picture.
• Press the stand-by button on the remote control to store.
Vertical Amplitude
Adjust the Vertical Amplitude so that the picture is over-scanned.
The effect of this adjustment is shown in figure 9.
• When the volume up button is pressed, the vertical size of the picture increases.
Fig.8
Fig.9
Fig.10
Fig.11
Fig.7
8
28HW-53H
Colour Adjustments
The following adjustments should only be carried out when
the CRT or IC801 are replaced.
G2, Cut Off and Gain Adjustments
1. Follow the procedure below to set the G2
1.1 Tune the set to the output of a signal generator
(cross hatch pattern).
1.2 In the user menu, set contrast to 80/100 and
brightness to 40/100.
1.3 Connect the oscilloscope to the red cathode and
adjust G2 to read 140V on the sensor pulse as
in the drawing:
NOTE:
Oscilloscope should be adjusted for vertical TV field trigger
and synchronized with video signal.
2. Follow the procedure below to set the Cut Off.
2.1 Adjust G2.
2.2 Tune a white card.
2.3 Adjust colour to minimum.
   140 V
CH1 gnd
2.4 Position colorimeter in the centre of screen.
2.5 Adjust brightness and contrast to obtain a lumi-
nance of 
≈20 NITS.
2.6 Operate in Service Mode and select location RED
CUT OFF, GREEN CUT OFF and  BLUE CUT
OFF, to obtain colour coordinates:
 X=0.290 ± 0.015       Y=0.284 ± 0.015
To increase press volume-up button and to decrease press
volume down button.
RED CUT OFF
 alter «X» coordinate.
GREEN CUT OFF  alter «Y» coordinate.
BLUE CUT OFF
 alter «X» and «Y» coordinate.
3. Follow the procedure below to set the GAIN.
3.1 Using brightness and contrast buttons, select a
luminance of 
≈120 NITS.
3.2 Operate in Service Mode and select location RED
GAIN, GREEN GAIN and  BLUE GAIN, to obtain
colour coordinates:
X=0.290 ± 0.015       Y=0.284 ± 0.015
To increase press volume-up button and to decrease
press volume down button.
RED CUT OFF
 alter «X» coordinate.
GREEN CUT OFF  alter «Y» coordinate.
BLUE CUT OFF
 alter «X» and «Y» coordinate.
3.3 Exit Service Mode and check colour coordinates
«X» and «Y» at 20 and 120 NITS. It may be nec-
essary to repeat procedure 2 and 3 of Colour
Adjustments.
Fig.12
Fig.13
• When the volume down button is pressed, the vertical size of the picture decreases.
• Press the stand-by button on the remote control to store.
S Correction
Adjust the S Correction so that the picture symmetrical between the top, centre and bottom.
The effect of this adjustment is shown in figure 12.
• When the volume up button is pressed, the top and bottom scanning increases and the
centre scanning decreases.
• When the volume down button is pressed the top and bottom scanning decreases and
the centre scanning increases.
• Press the stand-by button on the remote control to store.
Vertical Shift
Adjust the Vertical Shift so that the picture is centred.
The effect of this adjustment is shown in figure 13.
• When the volume up button is pressed, the picture moves up.
• When the volume down button is pressed, the picture moves down.
• Press the stand-by button on the remote control to store.
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28HW-53H
G2, Cut Off and Gain Adjustments (alternative method).
In the event off a Colorimeter not being available, please follow the following procedures to obtain correct G2 and Grey
scale settings.
1. Tune the set to the output of a RF signal generator (cross hatch pattern).
2. In the user menu, set the picture levels to the FACTORY settings.
3. In the user menu, set the tint control to its central position.
4. Enter the service mode.
5. Set the ABL levels in the NVM by adjusting positions 60, 61, 62, 63, 64 and 65 on page 00 to read 80.  Store each
location by pressing the stand-by button on the remote control.
6. Adjust the G2 and grey scale as below.
When adjusting the grey scale the following boxes will appear on the screen.
(RED)     (GREEN)     (BLUE)
(GAIN)                  **               **                **
(CUT OFF)      e.g. 70            **
      **
i. Using cross hatch pattern set the G2 so that the display in the Red cut off box reads between 60 and 80 as above.
NB.  When adjusting the grey scale, the figures displayed in the boxes are an indication of the CRT’s performance
only.  The data to be adjusted is contained in the box at the bottom right corner of the picture.
ii. Select a grey scale signal, then set the Red Cut-off level to 32 and the Red-Gain to 50.
iii.Leave the Red Cut-off and Gain as above and adjust Green and Blue Cut-off and Gain to achieve correct grey scale
tracking.  As with all grey scale adjustments it will be necessary to readjust the settings to achieve good tracking.
Changing NVM Data
To change the data contained within the Non Volatile Memory, it is necessary to first select the page the data is stored in,
then the position and finally to change the data itself.  The procedure below outlines this process.
1. While on ALTER NVM PAGE, use the volume up/down buttons to change this data (data is shown in hexadecimal
format).
2. Press the channel up button and ALTER NVM POSITION appears, use the volume up/down buttons to change this data
(data is shown in hexadecimal format).
3. Press the channel up button and ALTER NVM VALUE appears, use the volume up/down buttons to change this data
(data is shown in hexadecimal format).
4. Once this data has been set, press the standby button to store.
5. If another NVM value has to be changed, use the channel down button to select the page or position and repeat as
necessary.
Note:
DO NOT
 change any NVM data, unless you have been advised to do so by a Sharp representative.  If data is incorrectly
changed, serious damage may occur to the receiver.
Procedure to re-set the NVM:
Modify the NVM values as in the below table.
All the above values are hexadecimal.
NVM Page
NVM Position
Default Value
New value
00
7E
A5
A6
0C
20
Different on every set
Default value + 1
0C
61
Different on every set
Default value + 1
0D
3C
Different on every set
Default value + 1
0D
A5
Different on every set
Default value + 1
10
28HW-53H
Contrast Adjustments
Three types of contrast levels can be varied as listed be-
low:
• TELETEXT MIX MODE CONTRAST
• TELETEXT CONTRAST
• OSD CONTRAST
Use the volume up/down buttons to adjust to a suitable level,
then press the standby button to store.
DVCO Adjustment (PAL)
Carry out the DVCO Adjustment (PAL) as shown below:
1.
Receive a Phillips pattern signal.
2.
While in the DVCO ADJUSTMENT (PAL) menu, press
the standby button.
3.
DVCO Adjustment (NTSC)
No adjustment required.
Auto Installation On/Off
AGC Adjustment
To correctly align the Automatic Gain Control, follow the
procedure outlined below:
automatically.
AFT Adjustment
To correctly align the Automatic Fine Tune, follow the
procedure outlined below:
automatically.
LED FLASHING CODES
This model is not provided with stereo led, so to let “flashing
codes” for IC failures detection when the TV set does not
work, we have answered with the next solution:
• The detection of failure will be made with an external LED.
• The output of the flashing code will be via AV1 (pin 12).
• Insert a generic led diode between pin 12 and ground (i.e.
pin 5, 13 or 21) as shows the below picture.
Follow the sequence according to the information below, as
a guide to fault finding.
1. Unable to read or write into NVM: 66% ON, 33% OFF
twice and OFF for a second.
2.  MSP failure:  66% ON, 33% OFF for three times and
OFF for a second.
3. VDP failure: 66% ON, 33% OFF for four times and OFF
for a second.
NOTE:
If you want to check that the system is working, open resis-
tor R307 to avoid I
2
C comunication with MSP. The TV set
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