Sharp 26SL40 User manual

1
26SL40, 26SL70
29SL80
In the interests of user-safety (Required by safety regulations in some countries) the set should be restored to its
original condition and only parts identical to those specified should be used.
S69J129SL80//
MODELS
»ELECTRICAL SPECIFICATIONS......................................................................................................... 1
»IMPORTANT SERVICE SAFETY PRECAUTION .................................................................................2
»LOCATION OF USER'S CONTROL .....................................................................................................4
»INSTALLATION AND SERVICE INSTRUCTIONS................................................................................5
»CHASSIS LAYOUT............................................................................................................................. 11
»BLOCK DIAGRAM ............................................................................................................................. 12
»SCHEMATIC DIAGRAMS................................................................................................................... 15
»PRINTED WIRING BOARD ASSEMBLIES ........................................................................................ 33
»REPLACEMENT PARTS LIST............................................................................................................ 37
»PACKING OF THE SET...................................................................................................................... 47
Page
POWER INPUT........................................ 110-220 V AC 50/60 Hz
POWER RATING
26SL40..............................................................................120 W
26SL70..............................................................................125 W
29SL80..............................................................................130 W
PICTURE SIZE
26SL40, 26SL70 ................................... 2,032 cm2(315 sq inch)
29SL80.................................................. 2,193 cm2(340 sq inch)
CONVERGENCE............................................................. Magnetic
SWEEP DEFLECTION .....................................................Magnetic
FOCUS ................................................Hi-Bi-Potential Electrostatic
INTERMEDIATE FREQUENCIES
Picture IF Carrier Frequency ..................................... 45.75 MHz
Sound IF Carrier Frequency ...................................... 41.25 MHz
Color Sub-Carrier Frequency..................................... 42.17 MHz
(Nominal)
SHARP CORPORATION
CONTENTS
ELECTRICAL SPECIFICATIONS
Specifications are subject to change without
prior notice.
AUDIO POWER
OUTPUT RATING
26SL40............................................................. 2.5 W + 2.5 W
26SL70, 29SL80 .....................................................5 W + 5 W
(at 5% distortion and Dual CH Operate)
SPEAKER
SIZE ............................................................... 12 ×6 cm (2 pcs.)
VOICE COIL IMPEDANCE ...............................8 ohm at 400 Hz
ANTENNA INPUT IMPEDANCE
VHF/UHF ....................................................75 ohm Unbalanced
TUNING RANGES
VHF-Channels .............................................................. 2 thru 13
UHF-Channels ............................................................ 14 thru 69
CATV Channels........................................................... 1 thru 125
SERVICE MANUAL
26SL40, 26SL70
29SL80
COLORTELEVISION
Chassis No. SN-91A
POWER POWER PUSH OPEN MTS STEREO

2
26SL40, 26SL70
29SL80
IMPORTANT SERVICE SAFETY PRECAUTION
Service work should be performed only by qualified service technicians who are throughly
familiar with all safety checks and the servicing guidelines which follow:
X-RADIATION AND HIGH VOLTAGE LIMITS
1. Be sure all service personnel are aware of the
proceduresandinstructions coveringX-radiation.The
only potential source of X-ray in current solid state
TV receivers is the picture tube.However, the picture
tube does not emit measurable X-Ray radiation, if
the high voltage is as specified in the "High Voltage
Check" instructions.
It is only when high voltage is excessive that X-
radiation is capable of penetrating the shell of the
picture tube including the lead in the glass material.
The important precaution is to keep the high voltage
below the maximum level specified.
2. It is essential that servicemen have available at all
times an accurate high voltage meter.
The calibration of this meter should be checked
periodically.
3. Highvoltage should always bekept at therated value
−no higher. Operation at higher voltages may cause
a failure of the picture tube or high voltage circuitry
and;also, under certain conditions, may produce
radiation in exceeding of desirable levels.
4. Whenthehigh voltage regulator is operatingproperly
thereisnopossibilityofanX-radiationproblem.Every
timeacolorchassisisserviced,thebrightnessshould
be tested while monitoring the high voltage with a
meter to be certain that the high voltage does not
exceed the specified value and that it is regulating
correctly.
5. Do not use a picture tube other than that specified or
make unrecommended circuit modifications to the
high voltage circuitry.
6. Whentroubleshootingandtakingtestmeasurements
onareceiverwithexcessivehighvoltage,avoidbeing
unnecessarily close to the receiver.
Do not operate the receiver longer than is necessary
to locate the cause of excessive voltage.
WARNING
1. For continued safety, no modification of any circuit
should be attempted.
2. Disconnect AC power before servicing.
3. Semiconductor heat sinks are potential shock
hazards when the chassis is operating.
4. The chassis in this receiver has two ground systems
which are separated by insulating material.The non-
isolated (hot) ground system is for the B+ voltage
regulatorcircuit and thehorizontaloutputcircuit.The
isolatedgroundsystemisfor the low B+ DC voltages
and the secondary circuit of the high voltage
transformer.
To prevent electrical shock use an isolation
transformer between the line cord and power
receptacle, when servicing this chassis.
SERVICING OF HIGH VOLTAGE SYSTEM
AND PICTURETUBE
When servicing the high voltage system,
remove the static charge by connecting a
10k ohm resistor in series with an insulated
wire (such as a test probe) between the pic-
ture tube ground and the anode lead. (AC
line cord should be disconnected from AC
outlet.)
1. Picture tube in this receiver employs integral
implosion protection.
2. Replace with tube of the same type number for
continued safety.
3. Do not lift picture tube by the neck.
4. Handle the picture tube only when wearing
shatterproof goggles and after discharging the high
voltage anode completely.

3
26SL40, 26SL70
29SL80
12345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901212
1
234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890121
2
12345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901212
12345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901212
1
234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890121
2
12345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901212
SAFETY NOTICE
Many electrical and mechanical parts in television
receivers have special safety-related characteristics.
These characteristics are often not evident from visual
inspection, nor can protection afforded by them be
necessarilyincreasedbyusingreplacementcomponents
rated for higher voltage, wattage and etc.
Replacement parts which have these special safety
characteristics are identified in this manual; electrical
components having such features are identified by "å"
and shaded areas in the Replacement Parts Lists and
Schematic Diagrams.
IMPORTANT SERVICE SAFETY PRECAUTION
(Continued)
1. Inspect all lead dress to make certain that leads are
not pinched or that hardware is not lodged between
the chassis and other metal parts in the receiver.
2. Inspect all protective devices such as non-metallic
control knobs, insulating materials, cabinet backs,
adjustment and compartment covers or shields,
isolation resistor-capacity networks, mechanical
insulators and etc.
3. To be sure that no shock hazard exists, check for
leakage current in the following manner.
•PlugtheACcorddirectlyintoa110-220voltAC outlet,
(Do not use an isolation transformer for this test).
•Using two clip leads, connect a 1.5k ohm, 10 watt
resistorparalleledbya0.15µFcapacitorinserieswith
all exposed metal cabinet parts and a known earth
ground,suchaselectrical conduit or electrical ground
connected to earth ground.
•Use an AC voltmeter having with 5000 ohm per volt,
or higher, sensitivity to measure the AC voltage drop
across the resistor.
For continued protection, replacement parts must be
identical to those used in the original circuit.The use of
substitutereplacementpartswhichdonothavethesame
safety characteristics as the factory recommended
replacement parts shown in this service manual, may
create shock, fire, X-radiation or other hazards.
BEFORE RETURNINGTHE RECEIVER
(Fire & Shock Hazard)
Before returning the receiver to the user, perform
the following safety checks.
•Connect the resistor connection to all exposed metal
parts having a return to the chassis (antenna, metal
cabinet, screw heads, knobs and control shafts,
escutcheon and etc.) and measure the AC voltage
drop across the resistor.
AII checks must be repeated with the AC ine cord
plug connection reversed. (If necessary, a non-
polarized adapter plug must be used only for the
purpose of completing these check.)
Anycurrent measured mustnot exceed0.5milliamp.
Any measurements not within the limits outlined
above indicate of a potential shock hazard and
corrective action must be taken before returning the
instrument to the customer.
1.5k ohm
10W
0.15µF
TEST PROBE
CONNECT TO
KNOWN EARTH
GROUND
TO EXPOSED
METAL PARTS
AC
VOLTMETER

4
26SL40, 26SL70
29SL80
LOCATION OF USER'S CONTROL
POWER POWER MTS STEREO
VIDEO IN2 L-AUDIO-R– VOL + CH MENU
POWER POWER – VOL + CH MENU
TV
Infrared Transmitter Window
INPUT
Press →Switch to external video
INPUT 1 mode.
Pressagain →Switch toexternalvideo
INPUT 2 mode.
Press 3 times →Switch back to the
original TV mode.
CHANNEL UP/DOWN
( ) Selects next higher channel.
( ) Selects next lower channel.
• Moves the “ ” mark of the MENU
screen.
MENU
Press →Accesses MAIN MENU.
Press again →Exits MAIN MENU.
DISPLAY
Press→Displaysreceiving channel for
4 seconds.
Press again →Removes display.
• Temporarily displays receiving
channel when in Closed Caption
mode.
POWER
Press →On.
Press again →Off.
REMOTE KEYPAD
Accesses any channel from keypad.
FLASHBACK
Returns to previous channel.
VOLUME UP/DOWN
(+) Increases sound.
(–) Decreases sound.
• In menu mode, changes or selects
the TV adjustments.
MUTE
Press →Mutes sound.
Press again →Restores sound.
• CLOSED CAPTION appears when
sound is muted.
CHANNEL
UP/DOWN
() Selects next higher
channel.
() Selects next lower
channel.
SENSOR AREA FOR
REMOTE CONTROL VOLUME UP/DOWN
(+) Increases sound.
(–) Decreases sound.
POWER
Press →On.
Press again →Off.
VIDEO/AUDIO TERMINALS
(VIDEO/AUDIO terminals are also
provided on the rear.)
IN 2
MENU
Press →Accesses MAIN
MENU.
Press again →Exits MAIN
MENU.
Basic Remote Control Functions
Front Panel

5
26SL40, 26SL70
29SL80
CIRCUIT PROTECTION
The receiver is protected by a 5.0A fuse
(F5701),mounted on PWB-P,wired into one
side of the AC line input.
X-RADIATION PROTECTOR CIRCUIT TEST
After service has been performed on the horizontal
deflection system, high voltage system, B+ system,
test the X-Radiation protection circuit to ascertain
proper operation as follows:
1. Apply 110-220V AC using a variac transformer for
accurate input voltage.
2. Allow for warm up and adjust all customer controls
for normal picture and sound.
3. Receive a good local channel.
4. Connect a digital voltmeter toTP653 and make sure
that the voltmeter reads 11.2 ± 0.6V.
5. Apply external 13.8V DC at TP653 by using an
external DC supply, TV must be shut off.
6. To reset the protector, unplug the AC cord and make
ashort circuit betweenTP651 andTP652.Nowmake
sure that normal picture appears on the screen.
7. If the operation of the horizontal oscillator does not
stop in step 5, the circuit must be repaired before the
set is returned to the customer.
HIGH VOLTAGE CHECK
High voltage is not adjustable but must be checked
to verify that the receiver is operating within safe
and efficient design limitations as specified checks
should be as follows:
1. Connect an accurate high voltage meter between
ground and anode of picture tube.
2. Operate receiver for at least 15 minutes at 110-220V
AC line voltage, with a strong air signal or a properly
tuned in test signal.
3. Enter the service mode and select the service
adjustment "S19" and Bus data "01" (Y-mute on).
4. The voltage should be approximately, 28.7kV
(26SL40/70)/29.7kV(29SL80)(at zero beam).
Ifacorrectreadingcannotbeobtained,check circuitry
formalfunctioningcomponents. Afterthe voltagetest,
makeY-mute off to the normal mode.
INSTALLATION AND SERVICE INSTRUCTIONS
Note: (1)When performing any adjustments to resistor controls and transformers use non-metallic
screwdrivers or TV alignment tools.
(2)Before performing adjustments, the TV set must be on at least 15 minutes.