Sharp 28JF-73E User manual

1
28JF-73E
This document has been published to
be used for after sales service only.
In the interests of user safety (required by safety
regulations in some countries) the set should restored
to its original condition and only parts identical to
those specified should be used.
CONTENTS
ELECTRICAL SPECIFICATIONS ................... 3
IMPORTANT SERVICING NOTES ................. 4
CONTROLS & TERMINALS ........................... 5
ADJUSTMENT PROCEDURES ...................... 6
LED FLASHING CODES ............................... 12
PRINTED WIRING BOARDS ........................ 13
CHASSIS LAYOUT ......................................... 20
ICs ADDITIONAL INFORMATION .................. 22
SCHEMATIC DIAGRAMS ............................... 32
TROUBLESHOOTING TABLES ..................... 46
PARTS LISTING ............................................. 49
PACKING OF THE SET & ACCESSORIES ... 58
SOURCE OF DOCUMENTATION .................. 59
SHARP CORPORATION
MODEL 28JF-73E ES
PAL B/G, I / SECAM L/L’, B/G, D/K SYSTEM COLOUR TELEVISION
SE0028JF73E00
SERVICE MANUAL
Issued: 24th Sept. 2002
GA-20 CHASSIS

2
28JF-73E
Use this page to keep any special servicing information as Technical Report (Bulletin), Technical Information, etc.
If only part number changes are required, just change part number directly the part number in the Parts Listing Section.
If you need more information, please refer to the Technical Report (Bulletin).
SERVICE MANUAL UPDATE LOG SHEET
Part No.
Technical Report No.
Technical Bulletin No. Cause / Solution Page No. Application
Data /Serial No.

3
28JF-73E
ELECTRICAL SPECIFICATIONS
•White Level
Set brightness control to get total picture tube cathode current of 600 µA under no signal condition.
Maximum necessary correction of each picture tube cathode current to get 8550 degrees K+1 MPCD
screen temperature should not exceed 15% of its original value.
X=0.290 ± 0.015 Y=0.300 ± 0.015
WARNING
The chassis in this receiver is partially hot. Use an isolation transformer between the line cord plug
and power receptacle, when servicing this chassis.
To prevent electric shock, do not remove cover. No user-serviceable parts inside. Refer servicing to
qualified service personnel.
Specifications are subject to change without prior notice.
•Power Input .................... 220V-240 Volts AC 50Hz
•Power Consumption
Normal Operation (Method IEC60107) ............ 77W
Stand-by Operation ............................................ 3W
•Audio Power Output Rating (MPO) / Impedance
Internal Left Speaker ................................. 10W, 7Ω
Internal Right Speaker .............................. 10W, 7Ω
•Speakers
Left / Right ................................................. 13 x 6cm
•Convergence (Maximum Misconvergence)
Static (Centre) between any two colours ... 0.08 cm
Dynamic after static equals zero
Within 10cm (4”) circle ....................... 0.12cm
10-25cm (4-10” ) circle ...................... 0.20 cm
Everywhere else ................................ 0.28 cm
•Focus ................................. High Bi-Potential Electrostatic
•Sweep Deflection ................................................ Magnetic
MODEL DESTINATION (Operation Manual languages).
28JF-73E: Deutsch, Français, Nederlands.
28JF-73EES: Español, Português.
•Picture Intermediate frequency
L’ ................................................ 33.9MHz
L, B/G, D/K,I .............................. 38.9MHz
•Sound Carrier Trap
L’ ................................................ 40.4MHz
L, D/K ......................................... 32.4MHz
B/G ............................................ 33.4MHz
I .................................................. 32.9MHz
•Adjacent Sound Carrier Trap
L’ ................................................ 32.4MHz
L, D/K, B/G ................................ 40.4MHz
I .................................................. 40.9MHz
•Adjacent Picture Carrier Trap
L’ ................................................ 41.9MHz
L, D/K, ........................................ 30.9MHz
B/G ............................................ 31.9MHz
•Aerial Input Impedance
VHF/UHF ................. 75 ohm Unbalanced
•Tuning Ranges ..... 45.75MHz thru 855.25 MHz
VHF: IR A - J / S1 - S41 CH (Hiperband)
UHF: I21 - I69 CH
CATV Special Channels

4
28JF-73E
IMPORTANT SERVICING NOTES
Only qualified service personnel are allowed to carry out maintenance and repair of this receiver.
Servicing of High Voltage System and CRT
It is important that the static charge is removed from the high voltage system when carrying out work on the
receiver. This can be achieved by connecting a 10K resistor (with a suitably insulated lead) from the CRT
cavity connector to the CRT ground tag. This must be carried out with the AC supply disconnected from the
receiver.
Note the following:
•The CRT in this receiver employs Integral Implosion Protection.
•If the CRT has to be changed it MUST be replaced with the correct type for continued safe working.
•DO NOT lift the CRT by its neck.
•When handing the CRT, ensure that shatterproof goggles are worn.
•Ensure that the CRT is discharge before handling.
X-Ray
This receiver is designed to keep any x-ray emission to an absolute minimum. Some fault conditions and
servicing procedures may produce potentially hazardous x-ray radiation levels. This is a problem when in
close proximity to the receiver for long periods of time. To reduce any risks associated with this, please
observe the following precautions:
1. When undertaking any servicing on this chassis, DO NOT increase the EHT to more than 32.5 KV, (at a
instantaneous beam current of 1500µA).
2. Ensure that during normal operation the EHT does not exceed 30.0 KV±1.5KV (at a beam current of
1700µA). This level has been preset in the factory. Always check that this level has not been exceeded
after carrying out any repair on the receiver.
3. DO NOT replace the CRT with any other type than that specified in the parts listing as this may cause
excessive x-ray radiation.
Before returning the receiver to the customer
In addition to the above checks, the following should also be carried out before returning the receiver to the
customer.
1. Inspect all the leads to ensure that they are dressed correctly and that they are not obstructed or pinched
by any other parts.
2. Ensure that all protective devices are in good condition. These will include nonmetallic control knobs,
insulating fish papers, cabinets backs, compartment covers or shields, mechanical insulators, etc.

5
28JF-73E
1 2 3
HOW TO OPEN THE DOOR
Lift the projection at the lower right of the door with
your finger in the direction of the arrow.
8
42 3
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CONTROLS & TERMINALS

6
28JF-73E
REMOTE CONTROL
ADJUSTMENT PROCEDURES
All adjustments to this chassis, except for focus, are carried out in the Service Mode.
Service Mode
The Service Mode is provided to enable the engineer to correctly set up the receiver to the CRT fitted in the set.
Note that these adjustments may vary from one receiver to another.
To enter the Service Mode, carry out the following procedure.
1. Connect a test pattern to the antenna terminal.
2. Tune the receiver to this signal.
3. Turn the receiver off using the mains switch.
4. Press volume down and channel up buttons on the
front of the receiver at the same time.
5. Keeping these buttons pressed, turn the mains on.
6. When the set starts up it will be in Service Mode.
7. Release the two buttons. Figure 1
4
5
TV 1. Stand-by button (TV)
Video 2. Power button (VCR)
TV 3. 0 ~ 9 digit buttons
4. Flash back button
Teletext 5. GREEN button
6. RED button
TV 7. Volume DOWN button
8. MENU button
Teletext 9. REVEAL button
10. LIST button
11. STORE button
12. CANCEL button
13. HALF PAGE button
TV 14. RESET button
Video 15. Rewind/picture search reverse
16. Play button
17. Pause/Still button
18. Stop button
TV 19. TV/VIDEO button
20. Channel Call button
21. Single/Double entry button
Teletext 22. YELLOW button
23. BLUE button
TV 24. Channel UP button
25. Volume UP button
26. Channel DOWN button
27. Wide mode button
TV /Teletext 28. CLOCK button
TV 29. Sound mode button
Teletext 30. HOLD button
TV 31. Sound Mute button
Teletext 32. TEXT/MIX/PICTURE button
33. INDEX button
Video 34. Channel UP button (VCR)
35. Fast forward/picture search forward
36. Channel DOWN button (VCR)
37. Record button
1. 19.
23.
21.
24.
25.
26.
27.
28.
29.
30.
31.
32.
34.
37.
36.
35.
33.
22.
20.
4.
5.
6.
7.
8.
10.
11.
12.
13.
15.
18.
17.
16.
14.
9.
2.
3.

7
28JF-73E
••
••
•Use the channel up and down buttons to move between the options.
••
••
•Use the volume control buttons to change the data.
••
••
•To store the data, use the stand-by button on the remote control.
••
••
•To exit the Service Mode, turn the receiver off using the mains switch.
When the Service Mode is entered the following On Screen Display appears
SERVICE SOFTWARE ∗∗−∗∗x∗∗
SW on: XXXX SW off: XXXX Hours ON: XXXX
The figures displayed in the “XXXX” locations are hexadecimal representations of the number of times that particular
function has been executed. For example if the hexadecimal number displayed after “SW on” was 0E4A, this would
correspond to the receiver being turned on 3658 times.
The figure displayed in the “ ∗∗−∗∗x∗∗ ” location is the EPROM version.
X
Adjustment menu:
The following adjustments can be carried out in the Service Mode.
When in the Service Mode it is possible to access certain functions by using the teletext keys as below.
••
••
•By pressing the Blue button each adjustment can be directly accessed via the remote control. Referring to the
list above, press the Blue button followed by the adjustment number, this will directly access the selected
adjustment. If any number above 29 is selected, the set will revert to the Service Mode entry page. To access a
number less than 10, use the 0 key first, i.e. 02.
••
••
•Press the Yellow button to go straight to the AGC adjustment.
••
••
•Press the Green button once to enter “FACTORY VOLUME” level. Use volume control keys to change the
setting. The original value will be recovered after resetting the TV set.
••
••
•Press the Green button twice to enter “FACTORY BALANCE” level. Use volume control keys to change the
setting. The original value will be recovered after resetting the TV set.
••
••
•Press the Green button three times to enter “FACTORY BASS” level. Use volume control keys to change the
setting. The original value will be recovered after resetting the TV set.
••
••
•Press the Green button four times to enter “FACTORY TREBLE” level. Use volume control keys to change the
setting. The original value will be recovered after resetting the TV set.
••
••
•Press the Red button once to enter “FACTORY CONTRAST” level. Use volume control keys to change the
setting. The adjustment is stored automatically.
••
••
•Press the Red button twice to enter “FACTORY BRIGHTNESS” level. Use volume control keys to change the
setting. The adjustment is stored automatically.
••
••
•Press the Red button three times to enter “FACTORY COLOUR” level. Use volume control keys to change the
setting. The adjustment is stored automatically.
••
••
•If buttons 0 through 9 are pressed, the set will automatically go to that program number.
••
••
•By pressing the Menu button, the unit will normalise Picture and Audio settings. The Auto Installation is then
turned “on”.
01. Horizontal Shift
02. East West Width
03. Pin Phase
04. Pin Amp (Amplitude)
05. Corner Amplitude
06. Corner Symmetry
07. Vertical Linearity
08. Vertical Angle
09. Vertical Bow
10. Vertical Amplitude
11. S Correction
12. Vertical Shift
13. Red Gain
14. Green Gain
15. Blue Gain
16. Red Cut Off
17. Green Cut Off
18. Blue Cut Off
19. Alter NVM Pag (Page)
20. Alter NVM Pos (Position)
21. Alter NVM Val (Value)
22. Teletext Mix Mode Contrast
23. Teletext Contrast
24. OSD Contrast
25. DVCO Adjustment (Only PAL)
26. DVCO Adjustment (Only NTSC)
27. AGC Adjustment
28. Rotation Inspection
29. Auto Installation On/Off

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28JF-73E
Vertical
• Vertical Amplitude
• Vertical Shift
• Vertical Bow
• Vertical Angle
• S Correction
• Vertical Linearity
Horizontal Shift
Adjust the Horizontal Shift so that the picture is centred.
The effect of this adjustment is shown in figure 2.
•When the volume up button is pressed, the picture moves to the right.
•When the volume down button is pressed, the picture moves to the left.
•Press the stand-by button on the remote control to store.
E-W Width
Adjust the E-W Width so that 8% over-scan is achieved.
The effect of this adjustment is shown in figure 3.
•When the volume up button is pressed, horizontal scanning decreases.
•When the volume down button is pressed, horizontal scanning increases.
•Press the stand-by button on the remote control to store.
Pin Phase
Adjust the Pin Phase so that the picture is symmetrical top and bottom.
The effect of this adjustment is shown in figure 4.
•When the volume up button is pressed, side pincushion changes.
•When the volume down button is pressed, side pincushion changes.
•Press the stand-by button on the remote control to store.
Pin Amp
Adjust the Pin Amp so that the picture is centred.
The effect of this adjustment is shown in figure 5.
•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 barrel
shape to pincushion.
•Press the stand-by button on the remote control to store.
Figure 2
Figure 3
Figure 4
Figure 5
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Note that the receiver should be set to FULL MODE before carrying out any geometry adjustments. This can be achieved
by pressing the widescreen mode button on the remote control until FULL MODE appears on the OSD. This can only be
done out of the Service Mode.
The following geometry adjustments can be carried out. Detailed instructions on how to execute these are given on the
following pages.
Horizontal
• Horizontal Shift
• E-W Width
• Pin Phase
• Pin Amp
• Corner Amplitude
• Corner Symmetry
Just in case the TV set requires a full geometry adjustment, please proceed first with Vertical according to the above
order, and after that, adjust Horizontal according to the above order.

9
28JF-73E
Corner Amplitude
Adjust the Corner Amplitude so that the picture is centred.
The effect of this adjustment is shown in figure 6.
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 barrel shape to
pincushion.
•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 barrel shape to
pincushion.
• 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, the vertical angle changes to right.
• When the volume down button is pressed, the vertical angle changes to left.
• Press the stand-by button on the remote control to store.
Vertical Bow
Adjust the Vertical Bow so that the picture is centred.
The effect of this adjustment is shown in figure 10.
• When the volume up button is pressed, the vertical bow changes to right.
• When the volume down button is pressed, the vertical bow changes to left.
• Press the stand-by button on the remote control to store.
Vertical Amplitude
Adjust the Vertical Amplitude so that 8% over-scan is achieved.
The effect of this adjustment is shown in figure 11.
• When the volume up button is pressed, the vertical size of the picture increases.
• 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.
Figure 8
Figure 11
Figure 10
Figure 9
Figure 7
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Figure 6
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10
28JF-73E
Colour Adjustments
The following adjustments should only be carried out when the CRT or IC850 are replaced.
G2 (screen), R-G-B 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 (monoscope pattern).
1.2 In the user menu, set contrast to 80/100 and brightness to 40/100 (TV normalized).
1.3 Select FULL MODE.
1.4 Enter the Service Mode.
1.5 Select RED GAIN in Service Mode.
1.6 Adjust SCREEN VR so that the OSD value (indicated on Figure 14) reaches 50h ± 8h.
2. Follow the procedure below to set the Cut Off.
2.1 Adjust G2.
2.2 Tune a white pattern.
2.3 Adjust colour to minimum.
2.4 Position colorimeter in the centre of screen.
2.5 Adjust brightness and contrast to obtain a luminance of ≈ 3 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=0.300 ± 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 ≈100 NITS.
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 down.
• When the volume down button is pressed, the picture moves up.
• Press the stand-by button on the remote control to store. Figure 13
Figure 14
RED GAIN XX
XX XX XX XX
XX 50 XX XX
Adjust value
to 50h ± 8h
Figure 12

11
28JF-73E
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=0.300 ± 0.015
To increase press volume-up button and to decrease press volume down button.
RED GAIN alter «X» coordinate.
GREEN GAIN alter «Y» coordinate.
BLUE GAIN alter «X» and «Y» coordinate.
3.3 Exit Service Mode and check colour coordinates «X» and «Y» at 3 and 100 NITS. It may be necessary to repeat
procedure 2 and 3 of Colour Adjustments.
R-G-B Cut Off and Gain Adjustments (alternative method).
In the event off a Colorimeter not being available, please follow the following procedures to obtain correct and Grey
scale settings (R-G-B Cut Off and Gain).
1. In the user menu, set the picture levels to the FACTORY settings (normalised).
2. Enter the Service Mode.
3. Adjust the G2 as in the previous page procedure.
4. Set the 50, 51, 52, 53, 54 and 55 NVM positions on page 00 from the original value to 80. Store each location by
pressing the stand-by button on the remote control.
5. Adjust grey scale as follows.
5.1 Select a grey scale signal, then set the Red Cut-off level to 32 and the Red-Gain to 50.
5.2 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 neces-
sary to readjust the settings to achieve good tracking.
Note: The data to be adjusted is contained at the bottom right corner of the picture. See
Figure 15.
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. Press the channel up/down buttons and ALTER NVM PAG appears, use the volume up/down buttons to change this
data (it is shown in hexadecimal format).
2. Press the channel up button and ALTER NVM POS appears, use the volume up/down buttons to change this data (it is
shown in hexadecimal format).
3. Press the channel up button and ALTER NVM VAL appears, use the volume up/down buttons to change this data (it is
shown in hexadecimal format).
4. Once this data has been set, press the stand-by 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.
Contrast Adjustments
Three types of contrast levels can be varied as listed below:
• TELETEXT MIX MODE CONTRAST
• TELETEXT CONTRAST
• OSD CONTRAST
Use the volume up/down buttons to adjust to a suitable level, then. It is not necessary to press the stand-by button to store,
data are memorized by exiting the Service Mode.
Figure 15
BLUE GAIN XX
XX XX XX XX
XX XX XX XX

12
28JF-73E
DVCO Adjustment (PAL)
Carry out the DVCO Adjustment (PAL) as shown below:
1. Receive a Philips pattern signal.
2. While in the DVCO ADJUSTMENT (PAL) menu, press the stand-by button.
3. The adjustment will be carried out automatically and stored.
DVCO Adjustment (NTSC)
No adjustment required.
AGC Adjustment
To correctly align the Automatic Gain Control, follow the procedure outlined below:
1. Tune the set into a pattern generator on CH12.
2. Adjust the signal strength of the pattern generator to 59dB/µV (75Ω).
3. Enter the Service Mode.
4. Enter the AGC Adjustment menu.
5. Press the stand-by button on the remote control.
6. The adjustment will be carried out and stored automatically.
Rotation Inspection
No adjustment required. Just to check the proper working of this user feature. It cannot be memorized and after reset the
TV, the picture will appear normalized as other features.
Auto Installation On/Off
To return the receiver to the original Auto Installation mode, using the volume up or down button, set the Auto Installation
On/Off to On. This setting is automatically stored and when the receiver is turned on the next time it will start up in Auto
Installation mode.
LED FLASHING CODES
If the TV set does not work and the power indicator is flashing, 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. VCT failure: 66% ON, 33% OFF for four times and OFF for a second.
On Off
On Off
On Off

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