Sharp 8C221 User manual

m Service Manual
PAL SYSTEM
COLOUR TELEWSION
ELECTRICAL SPECIFICATIONS
Aerial Input Imp’edance
..................
75 ohm
Convergence.
...............
Self Converging System
Focus
...................
Bi-potential electrostatic
Audio Power Output Rating
.......... 2.0 Watt (max.)
Intermediate Frequencies
Picture IF Carrier Frequency.
......... 36,875 MHz
Sound IF Carrier Frequency
.......... 31,375 MHz
Colour Sub-Carrie;-Frequency . . 32,445 MHz (Nominal)
Powerlnput .................
.240VoltsAC50Hz
Power Rating
........................
165 Watt
Speaker Size.
................. 19 x 10cm Dynamic
Voice Coil Impedance ...........
.8 ohms (at 400 Hz)
Sweep Deflection .....................
.Magnetic
Tuning Ranges .............
VHF-Channels 0 thru 11
UH F Channels 28 thru 63
I
IMPORTANT SERVICE NOTES
Maintenance and repair of this receiver should be down by
qualified service persona4 only.
SERVICING OF HIGH VOLTAGE SYSTEM AND
PICTURE TUBE
When servicing the high voltage system, remove static
charge from it by connecting a 1 OK ohm Resistor in series
with an insulated wire (such as a test probe) between picture
tube dag and 2nd anode lead. (AC line cord shodd be
disconnected from AC outlet.)
1. Picture tube in this receiver employs ixitegral implosion
protection.
,\ 3. Replace with tube of the same type number for continu-
ed safety.
3. Do not lift picture tube by the neck.
4. Handle the picture tube only when wearing shatter-proof
goggles and after discharging the high voltage completely.
X-RAY
This receiver is designed so that any X-ray radiation is
kept to an absolute minimum. Since certain malfunctions
or servicing may produce potentially hazardous radiation
with prolonged exposure at close range, the following
precautions should be observed:
1. Do not adjust the high voltage level above 27.5 KV at
1 .lmA.
2. Do not substitute a picture tube with unauthorized
types and/or brands which may cause excess X-ray
radiation.
BEFORE RETURNING THE RECEIVER
Before returning the receiver to the user, perform the
following safety checks.
1. Inspect all lead dress to make certain that leads are nol
pinched or that hardware is not lodged between the
chassis and other metal parts in the receiver.
2. Inspect al4 protective devices such as non-metal4ic control
knobs, insulating fishpapers, cabinet backs, adjustment
and compartment covers or shields, isolation resistor-
capacity networks, mechanical insulators etc.
The manufacturer reserves the right to vary specifications or use alternative materials as may be deemed necessary or desirable
at any time, any such change or variation being of a kind as not to reduce the quality performance or appearance substantially.
SHARP CORPORATION OF AUSTRALLA PTY. LTD.
64-80 SEVILLE ST.,
FAIRFIELD, 2165
N.S.W. TEL: [phone]

INSTALLATION AND SERVICE ADJUSTMENTS
INSTALLATION OF NEW COLOUR TELEVISION
RECEIVER
Adjust the receiver for a black and white picture. Check
the horizontal oscillator adjustment, focus, vertical size
and linearity. Observe the picture for good
black-and-
white reproduction over all areas of the screen. No ob-
jectionable colour shading should be evident. If shading
is evident, demagnetize the receiver. It is seldom necessary
to go through a complete “set-up” routine when installing
a new colour receiver. In the majority of cases a technician
needs only to degauss the face plate area of the picture
tube and touch up the static convergence.
Colour television receivers leaving the factory are adjusted
by experts who specialize in the set-up of colour receivers.
Normally, readjustment of picture tube temperature or
even dynamic convergence should not be required upon
delivery. However, since a receiver or parts of it, may
become magnetized as it is transported from one location
to another, it is very important to demagnetize the picture
tube face plate area once the receiver is set in its final
operating position.
DEGAUSSING
This receiver is equipped with an automatic degaussing coil
which effectively demagnetizes the picture tube each time
the receiver is turned on. The degaussing coil will operate
at any time the set is turned on after having been off for at
least five minutes.
Since this degaussing effect is confined to the picture tube,
should any part of the chassis or cabinet become magnetized,
it will be necessary to degauss the affected area by means of
a manual degaussing coil. Move the coil slowly around the
parts to be demagnetized, then slowly withdraw for a
distance of six feet before disconnecting the coil from
the AC power supply.
Note:
Degaussing (or demagnetising) is an important
function in the setting up and installation of colour T.V.
receivers.
The receiver should be positioned in its foal
location before degaussing because of possible loss of
purity due to the re-location of the receiver.
Because of possible loss of purity caused by the re-location
of the receiver, the cabinet should be positioned in its
final location before degaussing.
MODULE SERVICE PERCAUTIONS
1. DO NOT remove or insert module units whilst the set is
switched on.
2. Semiconductor heat sinks should be regarded as potential
shock hazards when the receiver is operation.
HOWTOADJUSTTHECHANNELSETTING(UHF/VHF)
(1) Touch the Channel Selector Button corresponding to
the channel, that you wish to select.
(2) Adjust the Band Selector switch to either of 3
positions (VL, VH , U) as shown below, depending on
what channel you now wish to select.
BAND VL . . . . . . . . .
VHF 0 - Sch.
BANDVH . . . . . . . . .
VHF5A-llch.
BANDU
. . . . . . . . . UHF21-69ch.
(3) Note the number on the Channel Selector Button and
relate it to the Preset Tuning knob and Band Selector
switch with corresponding number.
(4) Tune in the desired channel by turning the Preset
Tuning knob clockwise or counterclockwise until the
channel is properly tuned.
Note:
Whenever the ON-OFF switch is turned on, No. 1 program
will always be selected. However, when you want to change
this No. 1 program to another program by depressing the
channel selector button, it sometimes occurs that the
corresponding indicator lamp does not light up - this
means that your desired program has not been selected.
In this case, set the ON-OFF switch to “OFF” position and
reverse the polarity of power cord. Then, the unit will
function normally, assuring a proper program selection. The
aforesaid, however, may take place only when the antenna
terminal is grounded or a separate transformer is used as a
power supply source and, therefore, this is out of the
question as long as you operate the unit in a normal receiv-
ing condition.
Preset Channel Table
(at factory setting)
No. 1 A2
No.2 Al
No. 3 ASA
No.4 A6
No. 5 A2
No. 6
E23
No. 7 E34
No. 8 E68
Figure 1. Front Panel Controls
7

HIGHVOLTAGECHECK
High voltage is not adjustable but must be checked to
verify that the receiver is operating within safe and efficient
design limitations as specified:
1.
2.
3.
4.
If
Remove cabinet back.
Operate receiver for at least 15 minutes, with strong air
signal or test signal properly tuned in.
Set Brightness and contrast controls to maximum
position.
Connect an accurate high voltage meter to CRT anode.
Reading should be 24.5 + 1 SW. (at 1 .15mA)
correct reading cannot be obtained, check circuitry for
malfunctioningcomponents.
FOCUS
Adjust the Focus control(R667), located on the rear of the
TV chassis, for maximum over-alldefinition and fine picture
detail with Brightness and Contrast controls set at normal
viewinglevels.
VERTICAL SIZE AND LINEARITY
The Vertical Linearity control (RS 15) primarily affects the
top of the raster while the Vertical Size control (R517)
primarily affects the bottom of the raster. However,
there is some interaction between these two controls.
Vertical Centering properly positioned and Brightness and
Contrast controls adjusted for normal picture, alternately
adjust Vertical Linearity and Vertical Size controls to
obtain a linear picture.
HORIZONTAL OSCILLATOR ADJUSTMENT
The receiver should be operating for at least 10 minutes
before proceeding.
1. Tune in a local station and set the Horizontal Hold
control (R618) at the center of its rotation.
2. Connect a short clip lead between test point TP401
and ground.
3. Adjust the Horizontal Frequency Control (R617) to
obtain minimum horizontal movement of the picture.
4. Remove a short clip lead between test point TP401 and
ground.
5. Check the operation of the Horizontal Hold control to
verify that the picture is porperly synchronized with the
control set at the mechanical centre of its range.
RF AGC ADJUSTMENT
The receiver should be operating for at least 10 minutes
before proceeding.
1. Connect a 58db input signal to the antenna terminal.
2. Connect VTVM to TP204.
3. Fully turn RF AGC control (R206) counter-clock-
wise.
4. Observing the indication of VTVM, slowly turn RF
AGC control (R206) clockwise and fix it when the
voltage starts to fall.
+13OV ADJUSTMENT
The +13OV Adj. control (R724) is adjusted at the factory.
However, should readjustment be required, proceed as
follows:
1. Operate receiver for at least 15 minutes.
2. Connect positive lead of VTVM to TWO 1, negative lead
to chass is ground.
3. Rotate +13OV Adjust control (R724) to clockwise and/
or counter clockwise until a VTVM reading of DC 13OV.
4. Remove VTVM to TP?Ol.
CAUTION:
Do not exceed 130 volt for protecting
the set from failure.
H-SIZE ADJUSTMENT
Since the horizontal amplitude of receiver has been com-
pletely adjusted before delivery from the factory, normally
readjustment should not be required. However, if it
becomes necessary for any reasons, take the following steps.
1. Receive cross-hatch pattern.
2. Rotate H-Size coil (L608) until over scanning is more
than 6 percent.
CENTERING ADJUSTMENT
H-Center Adjustment:
If the picture is one-sided from right to left of the screen,
rotate H-CENT adjust control (R627) until the picture is
centered.
V-Centre Adjustment:
If the picture is one-sided from top lo bottom of the
screen, change V-CENT adjust tip to adjust so that the
picture is centered.
PINCUSHION ADJUSTMENT
The pin-cushion adjustments are preset at the factory and
normally need no further adjustment. However, if necessary,
corrections can be made by adjusting for straight horizontal
lines at the top and bottom of the rester.
The receiver should be allowed to operate for at least five
minutes with a cross-hatch pattern displayed on the screen.
Top and Bottom Pincushion Adjustment
1. Adjust the Pincushion coil (LSO 1) to move the maximum
curvature of the horizontal lines to the center of the
screen.
2. Adjust the Pincushion Transformer Magnet (TSOl) so as
to straighten out the horizontal lines at both the top and
bottom of the screen.
Side Pincushion Adjustment
1. Rotate the Side Pin. Phase control (R638) until the pin-
cushion distortion is at the centre of screen.
2. Rotate the Side Pin. Amp. control (R639) to compensate
for pincushion distortion until vertical lines at both sides
of screen are straight .
3

WHITEBALANCE ADJUSTMENT
The purpose of this procedure is to optimize the picture
tube to obtain good black and white picture at all brightness
levels while at the same time achieving maximum usable
brightness. Normal RF AGC setting and purity adjustments
must procede this procedure.
This adjustment is to be made only after a warm-up
operation is provided for 5 minutes at least.
With antenna connected to the receiver, tune in picture
on a strong channel.
Rotate the Colour control (R839) to maximum CCW
position and misadjust pre-set Tuning so that the receiver
will not produce a color picture while the following
adjustments are being performed.
1. Set the Green Drive (R1015) and Blue Drive (R1016)
controls to mid-position.
2. Rotate the Red, Green and Blue Bias controls to the full
CCW end of their rotation ranges.
3. Set the Service Switch, on PWB-B, to Service position.
4. Rotate the Screen control (R1032), to the full CCW
end of its rotation range. Then, rotate it CW until a
dim raster of one pronounced color (Red, Green or
Blue) is obtained.
5. The other two color Bias controls must be rotated CW
until a dim white raster is obtained.
6. Set the Service switch to Normal position
7. Set the Brightness control (R480) to maximum.
8. Set the two Drive controls to obtain best white uni-
formity on the picture tube screen.
9. Rotate the Brightness control to minimum.
10. Rotate the Brightness control to clockwise until a dim
raster is obtained.
11. Touch-up adjustment of the three Bias Controls to
obtain best white uniformity on the screen.
BEAMCURRENTADJUSTMENT
Black and white tracking procedure must have been com-
pleted before attempting this adjustment.
Operate receiver for at least 15 minutes and with antenna
connected to the receiver, tune in picture on a strong
channel.
1. Connect voltmeter positive probe to TP603 and negative
probe to TP602, on PWB-B.
2. Rotate Brightness and Contrast controls to maximum.
3. Adjust s-lb contrast control (R671) to obtain a reading
of 1.15v.
PURITYADJUSTMENT
Before purity adjustment can be made, the receiver
should be demagnetized and allow to run with full bright-
ness (without bloom) for a minimum of 10 minutes and
static convergence must be correct.
1. With antenna connected receiver.
2. Fully turn the R-Bias (R1007) and B-Bias (R1009)
controls counterclockwise to get green alone.
3. Loosen the clamp screw for deflection yoke and draw it
back as much as possible.
4. Turn the purity magnet rings and fn them so that a
green band is produced and that red and blue bands are
made at the right and left.
5. Slowly slide the deflection yoke forward and fuc it by
tightening up the clamp screw when the best over-all
green is obtained in the screen.
6. When purity is not achieved, repeat the steps 3, 4 and
5, then the best purity can be obtained.
7. Fully turn the G-Bias control (R1008) counterclockwise
and then the R-Bias control clockwise. Check if the
purity of red has been achieved. After that, check
the purity of blue as well.
DEFLECTLON YOKE
H-SIZE COIL
6-POLE MAGNET
PURITY MAGNET
Figure 2.
CONVERGENCEADJUSTMENT
Any colour impurity induced as a result of relocation of
the receiver normally will be removed by the Automatic
Degaussing Operation. The
degaussing recurs any time
the receiver is turned on, after being off for at least 5
minutes.
The receiver, with the Brightness and Contrast controls
in normal position, should be operated for minimum of
10 minutes before proceeding. Also, adjustments such as
purity, vertical size and vertical linearity must be made,
as directed in this manual, before attempting convergence
adjustment.
Connect the cross hach pattern Generator to the VHF
antenna terminals of the receiver and turn the receiver to a
channel suitable for operation with the particular generator
being used.
4

Static Convergence Adjustment
1. Rotate two pieces of 4-pole magnet in different direc-
tions reverse to each other so as to make the same the
vertical lines of red beam and blue beam.
2. Rotate both magnets in combination without changing
the created angle between them and fix them when the
vertical line and horizontal line for both red beam and
blue beam are the nearest.
3. Rotate both magnets gradually in different direction
until the red line and Blue line are focussed upon
one to another producing a mazenta line.
4. Rotate two pieces of 6-pole magnets to bring the green
line onto the mazenta line.
CHASSIS REMOVAL
1. Loosen the back cover retaining screws and separate the
back cover from cabinet.
2. In this position the chassis can be inspect from all sides.
3. Remove PWB-B chassis (deflection PWB) retaining
screws.
4. After all plug connections on PWB-B and picture tube
anode cap have been disconnection the PWB-B chassis
can be pulled out of the cabinet.
5. Remove PWB-E chassis (power PWB) retaining screws.
6. After all plug connections on PWB-E have been discon-
nection the PWB-E chassis can be pulled out of the
cabinet.
7. When remove the PWB-A chassis (signal PWB) after pull
out of the all connections on PWB-A and pull out the
PWB-A chassis.
PICTURE TUBE ASSEMBLY REMOVAL AND REPLACE-
MENT
1.
2.
3.
4.
5.
6.
7.
8.
Remove PWB-B and PWB-E chassis from cabinet.
(Refer to CHASSIS REMOVAL procedure)
Disconnect picture tube coating earth tip from the PWB-
C.
Unplug picture tube socket board (PWB-C) from picture
tube.
Spread a heavy pad on blanket on the wark surface to be
used to prevent scratching the cabinet and carefully
place cabinet face down on this protective covering.
Remove the four nuts that secure the picture tube
mounting tubs to the front frame.
Carefully grasp the picture tube assembly by its mounting
tubs and lift from the cabinet front.
The picture tube must be handled with care.
Remove the picture tube dag ground harness assembly.
Carefully seat the new picture tube assembly in place on
the cabinet front and install all hardware in reverse other
sequence.
5

GENERALALIGNMENTINSTRLJCTION
Equipment
The test equipment specified on page 7 or its equivalent,
is required to properly perform the alignment procedures
which are outlined on the following pages. Use of equip-
ment which does not meet these requirements may result
in the inability to properly align the instrument.
A warm-up period of at least fifteen minutes should be
allowed for proper stabilization of equipments such as
Marker and Sweep Generators.
It is essential that the proper bias values, as specified,
are maintained during alignment to insure the proper
results.
Equipment Terminations
The alignment pads and the input lead are designed for
correct matching of the equipment to the circuits involved.
Failure to use proper matching will result in responses
which cannot be depended upon as representing the true
operation of the receiver. The pads should be constructed
as compactly as possible and all unshielded leads at the end
of the test equipment cables should be as short as possible,
preferably not in excess of one inch long. In many
instances a small ceramic capacitor, approximately lOOOPF,
connected from the oscilloscope probe to ground will
eliminate stray pick-up of unwanted signals. If used, make
sure the capacitor does not affect the shape of the response
being observed.
Signal Overload
Use of excessive signal from the Sweep Generator can cause
overloading of the receiver circuits. To determine that this
condition is not present and that the response curve is true,
turn the Sweep Generator output to zero and then gradually
increase the output until a response is obtained. Further
increase of the sweep output should not change the con-
figuration of the response except in amplitude. If the
response changes in configuration, such as flattening at the
top or dropping below the base line at the bottom, decrease
the sweep output to restore the proper configuration. The
oscilloscope gain should be run as high as possible to main-
tain a usable pattern with the peak-to-peak values specified,
thus requiring a lower output from the Sweep Generator
and less chance of overload.
Insertion of markers from the Marker Generator should
not cause distortion of the response curve. The markers
should be kept as small as possible and still remain visible.
6

TESTEQUIPMENT
To facilitate service and alignment for this chassis, it is
recomended that the following test equipments should be
used.
VARIABLE POWER SUPPLY . . . .
Range: DC 0 . . .25V
TEST PATTERN GENERATOR
VOLT METER . . . . . . . . . . . High input
inpeadance type.
SWEEP GENERATOR.
MARKER GENERATOR . . . . . . . With crystal caliblated
accuracy.
OSCOLLOSCOPE
IF-TEST BLOCKS . . . . . . . . . . . . . . . .
Shown in Fig. 3.
VIDEO DETECTOR TEST BLOCK . . . Shown in Fig. 4.
OUTPUT PADS
. . . . . . . . .
Shown in Fig. 5 (A) (B) (C).
(A)
TO TEST POINT
loop
I N60
47K -- I5000
.
CHASSIS
Figure 3. IF Test Block
Figure 4. Video Detector Test Blodc
TO TEST POINT
I
001
5.6K
CHASSIS
SWEEP
GENERATOR
CHUSi
(A) SIF Sweep Generator Output Pad
(B) PIF Sweep Geneator Output Pad
SWEEP
GENERATOR
SWEEP
GENERATOR
CHfiSIS
ICI Chroma Sweep Generator Output Pad
Figure 5. Output Pad
7

TUNER PERFORMANCE CHECK
Preliminary Information
Unless there is evidence of tempering or if electrical repairs
have been made tuner alignment is normally not required.
Response Curve
“A” is an indicator of the quality of tuner
performance. If the response curve is obviously bad on all
channels,repair, ratherthan alignment,is indicated.
Also check for bad solder connections and contacts.
Visually inspect the circuits for overheated components
and obvious wiring defects.
Test Equipment Connections: Refer to Figure 6.
GENERAL . . . .
The set under -test should be correctly
fine tuned, fine tuning should not be adjusted while
performing this tuner check.
OSCILLOSCOPE . . . With at 1 .OV P-P calibration, connect
to terminal TP203.
SWEEP GENERATOR . . . ..Connect output to the tuner
aerial terminals using proper matching pad.
MARKER GENERATOR
. . . . . . . . Connect markers at loosely
to Sweep Generator output lead.
BIAS SUPPLY . . . . . . . . . . . . . . . .
Apply +7.S volts bias to TP204.
Performance Check
Starting with the tuner placed in the Channel 12 position
and the Sweep Generator .set at the proper frequency, check
the overall response curve as viewed on the Oscilloscope.
This viewed curve should match, approximately, Response
Curve “A”. The same procedure should be used for
Channels 11 through 0.
.
31.375
Response Curve “A”
Figure 6. Tuner Performance Check

PICTURE IF TRANSFORMER & TRAP ALIGNMENT
Test Equipment Connections: Refer to Figure 7.
GENERAL . . . . . . . . . . . . . . . .
Connect AC power plug through
isolation transformer to power supply.
BIAS SUPPLY . . . . . . . . . . . .
Apply t8V volts bias to TP204.
OSCILLOSCOPE
. . . . . . Connect to TP203 through “IF TEST
BLOCK” shown in Figure 3. Detector terminal B
is connected to TP201.
SWEEP GENERATOR . . . . . . .
Connect IF/VF output in
series with “Out Put Pad” shown in Figure 5 to
TP201.
MARKER GENERATOR
. . . . . . Couple loosely to Sweep
Generator Output Cable to provide markers.
VTVM . . . . . . . . . . . . .
Used to check bias voltage.
Note: . . . . . . . Preset RF AGC control to mid-position. Set
Channel Selector to Channel 10.
Alignment Procedure
. . . . . . . . . See “General Alignment In-
struction” before attempting alignment.
STEP
4
5
6
7
8 Recheck adjustment of Tl on tuner and T201 for correct response as shown in “B” of Figure 7.
9
10
11
12 Reset RF AGC control (R206) for normal operation.
ADJUSTMENT
WEEP
GENERATOR MARKER
GENERATOR
COMPONENT
PROCEDURE
Detector stage 30-42MHz
36.875MHq
32.445MHz
3 1.375MHz
T206
(bottom core)
Adjust as shown on response curve “A” of
Figure 7.
Adjust 3 1.375MHz
attenuation of PIF Same as Step 1 31.375MHz T206
Adjust T206 (Top core) alternately for
(Top co=)
maximum attenuation of 31.375MHz as
Det. transformer. shown on response curve “A” of Figure
7.
Recheck adjustment of I206 (Bottom core) for response as shown in “A” Figure 7.
Remove the Sweep Generator lead from TP201 and reconnect it to test point on tuner.
Remove the IF Test Block terminal A from the TP203 and reconnect it to TP201 of IF Test Block terminal B.
Apply +8.0 volts ACC bias to TP204.
Set channel selector to channel 10.
Check 31.375MHz
38.375MHz
Adjacent channel
trap & sound trap
transformers
Same as Step 1
Adjust mixer col-
lector coil in VHF
tuner
Same as Step 1
Adjust 1st PIF
transformer Same as Step 1
31.375MHz T202
Adjust for minimum dip at 31.375 MHz,
38.375MHz T203 38.375MHz.
3 1.375MHz
32.445MHz
36.875MHz
38.375MHz
Tl on
Adjust for maximum gain and the response
VHF Tuner curve
“B” in Figure 7.
Same as Step 6 T201
Remove the IF Test Block terminal B from the TP201 and reconnect it to TP203 of IF Test Block terminal A.
Apply +8.0 volts ACC bias to TP204.
Adjust for proper
PIF curve Same as Step 1 Same as Step 6
T204
T205
Align T204 and T205 for maximum gain and
obtain the response as shown in “C” Figure
7.
Recheck adjustment T204, T205 and for correct response as shown in “C” Figure 7.
9

3 1.375
Response Curve “A”
31.376 38.376
Response Curve %”
Figure 7. PIF Transformer and Trap Alignment
10

RF AFT ALIGNMENT
Test Equipment Connections* Refer to Figure 9 .
GENERAL . . . . . . . . . . . . . . . .
Set channel selector to the highest
unused channel. Read the General Alignment
Instruction (Page 6)
Connect. AC power plug through the isolation trans-
former to power supply.
oscILLOscoPE . . . . . . . .
Connect through a direct probe to
TP201. Calibrate for a two inch equal OSV P-P
display.
Note:
Set base line in centre of CRT for reference.
SWEEP GENERATOR . . . . . . .
Connect the IF video output
through the Output Pad A or B. (Figure 5 ) Set
for a 1 V P-P output.
MARKER GENERATOR . . . Adjust to produce 36.875
MHz couple loosely to Sweep Generator output cable
to provide marker.
ALIGNMENT PROCEDURE
Before attempting this alignment, check the PIF response and realign if necessary. Make sure that the signal appearing at the
output of the video detector has an amplitude of 1V P-P.
STEP ADJUSTMENT
SWEEP MARKER
GENERATOR GENERATOR
COMPONENT PROCEDURE
1
I
Readjust Marker Generator for visible 36,875MHz marker, if necessary, without distorting the response cuIye.
2
Move the core of T201 to its bottom end of range.
3 AFT Transformer
35 - 40MHz
36.875MHz 1208
Adjust T208 to obtain the maximum amplitude
I
and response cuve “A” as shown in Figure 8.
4
AFT Discriminator
35 - 40MHz.
36.875MHz T209
Adjust T209 to bring 36.875MHz marker to the
centre of S curve “B” as shown in Figure 8.
5
APT Transformer 35 - 4OMHz.
36875MHz
T208
Adjust T208 to make the S curve symmetrical
as shown in Figure 8.
6 ( Repeat Steps 3 through 5 so that the final response curve matches Response Curve, “B”.
When property aligned maximum allowable amplitude ratio above and below zero reference is approximately A=B.
7 (See Response Curve “B”).
Check all channels for same response, if response is not the same, adjust T208, T209 for each charmeL
With the tuner set to an outside signal, observe whether or not the AFT locks in a black and white station and a colour station.
8 Note:
If AFT is found to lock in B/W but not colour, perform the Burst Alignment. If AFT does not B/W or colour, repeat this
AFT alignment.
36.875MHz
Respmse Curve “A”
Response Curve “B”
1%
Figure 8.

T3Ol
T206
cl 0
Q 0207
1200
T205
-0 TP206 cl
0
0 0206
0 TP205 0
0 T203
0
0 0 T202
Q202
0
Q 00205
0204
cl 0 TPOI
( ouT,:, /---
Figure 9. RF AFT Alignment
12

SOUNDIFDETECTORALIGNMENT
The following alignment procedures are accomplished with
the receiver operating normally while connected to an
antenna and tuned to receiver a local telecast.
STEP
I
ADJUSTMENT
I
COMPONENT
I
PROCEDURE
1 Transformer Input
2 Discriminator
T301
T302
Adjust the input transformer for maximum sound.
Adjust the discriminator for least distortion with maximum
sound and minimum buzz.
VIDEO TRAP(4.43MHz)ALlGNMENT
GENERAL . . . . . . . . . . . Connect AC power plug through the isolation transformer to power supply.
STEP
1
PROCEDURE
Connect Colour Bar Generator to receiver antenna terminals. Switch Pattern control to Colour Bar Position. Adjust receiver
for normal colour reception.
2
Connect Oscilloscope to TP404.
3
I
Adjust the Video Trap (T401) for minimum chroma carria in the Video signal.
R454
R436
ADJUST
VIDEO
RB24
-
I
SUB CONTRAST
“T401 f
“2 E-l
nTPL
I 0 0 n” II I, I uLo”‘l I I
TP402
w
l-l
YU
0413 0412
D
“‘“‘0 17 O yip808
0
I I r
Lj ,
Figure 10. Video Trap Alignment
13

PEDESTAL LEVEL ALIGNMENT
Tune in a black and White Signal. The receiver should
have been operating at least 10 minutes before proceeding
with Pedestal Level Alignment.
Connect AC power plug through the isolation transformer
to power supply.
STEP PROCEDURE
1 Set the Brightness control to mid. positions.
2
Set the R-Drive, G-Drive and B-Drive controls to mid range.
3
Set the R, G and B Bias controls to minimum (fully CCW)
4
Connect oscilloscope to collector of red output transistor ((21001)
5
Connect a short clip lead between TP402 and TP403.
6
Adjust the Pedestal control (R436) to make the pedestal level be aligned with the pulse level (A) of the waveform drawn on an
oscilloscope.
7
Adjust the white balance in such manners as in page 4.
/
J-J-
(A)
______--______ 1 - -_____________ DC130V
Waveform “A”
q
T6Ol
0
0 0
TP TP
810 809
TP806
SUB-COLOR u SUB-CONT
1
L40
0’4’0
OTP
402
0 TP401
-
0 TP404
PEDESTAL LEVEL
0
@ R436
PEDESTAL
RI032
RI015
RIO07
Figure 11. Pedestal Level Alignment
14

CHROMABANDPASSALIGNMENT
Test Equipment Connections:
Refer to Figure 12.
OSCILLOSCOPE . . . . . .
GENERAL
Connect to TP802 through “Video
. . . . . . . .
Connect AC power plug through the
Detector Test Block” shown in Figure 4.
isolation transformer to power supply. SWEEP GENERATOR
. . . . . . . . . . .
Connect the IF Video Out-
Set Channel selector to the highest unused channel. put through the Out Put Pad. (Refer to Figure
5 ).
Preset Colour control to approximately midposition.
MARKER GENERATOR
. . . . . . . .
Connect as shown.
Set the Contrast control to maximum. Connect a
SIGNAL GENERATOR . . . . . . . . . . . .
Connect as shown Produce
short clip lead between TP806 and 807.
of 36.875MHz signal.
BIAS SUPPLY . . . . . . . . . . .
Apply t7.5 volts bias to TP204.
RF MODULATOR
. . . . . . . . . . . . . . . . . .
Connect as shown.
OUT PUT PAD . . . . . . . . . . . . . . . . . . . . . . . . .
Connect as shown.
VTVM
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Check to bias voltage.
STEP ADJUSTMENT SWEEP
MARKER
GENERATOR GENERATOR
COMPONENT
PROCEDURE
1 Set the Colour control to centre of its range.
2
Apply output of Sweep Generator to the RF Modulater.
Set the Colour control to the centre of it range.
3
Apply 7.W bias to TP204.
4
Bandpass Trans. 4.4MHz
TZOS
6466
TC601g
0 0207
(TCI
1202 I-J
DL6Ol
(TS) r-1
T206 1205
0 TP206
(TA) [I
Figure 12. Chroma Bandpass Alignment

4.43MHz OSCILLATOR AND COLOUR SYNC. ALIGNMENT
Test Equipment Connections: Refer to Figure 13.
OSCILLOSCOPE
. . . . . . . . . . . .
Connect through direct probe
GENERAL . . . . . . .
Connect AC power plug through the isola-
described. The frequency response of vertical input
tion framsformer to power supply. should be flat to at least
MHz.
Set the Colour control to the centre of its range.
COLOUR BAR GENERATOR
......... ..Connect to receiver
Set the receiver to normal operation. antenna terminals. Switch Pattern control to Colour
Bar position. Adjust receiver for normal colour
reception.
4.43MHz OSCILLATOR ALIGNMENT
STEP
ADJUSTMENT
COMPONENT PROCEDURE
1
Connect Oscilloscope to TP805 (Vertical range O.SV/cm)
2
Adjust 4.43MHz T803
Adjust T803 for maximum deflection on scope.
(CW Trans.)
(Output level 1 .l * 0.3V p-p)
COLOUR SYNC. ALIGNMENT
STEP
ADJUSTMENT
COMPONENT
I
PROCEDURE
1
Connect a short clip lead between TP806 and TP807.
Turn the Colour Killer control to fully counter cloc!:wise position.
2
Adjust APC Trans. T802
Adjust APC Trans (T802) to obtain colour sync.
3
Remove a short clip lead between TP806 and TP807.
Chedc whether colour sync. obtain or not.
R454
R436
ADJUST
SUB CARRIER
ADJUST
AR C
TRANSFORM ER
0407
-
R824
T801 -
COLOR
--\- tot
0
0408
SUB CONTRAST
0
0’
0
0
w
9802
3 TP802
m)TP
PEDESTAL 040g
0
T 401
0 0 0402 8 TP
0
TP403
0410 ‘04
0 0
no
rP402
[-I @&Ap
TP80
L
T804
n-
:K)
l-J
0
TP803s0
DL801
rl
0
0404
1821
Figure 13. 4.43MHz Oscillator and Colour Sync. Alignment

PALDELAYCIRCUITALIGNMENT
STEP
1
ADJUSTMENT
COMPONENT
Set the Colour control to centre of its range.
Connect Oscilloscope to TP803.
PROCEDURE
2
Adjust Delay Time
control
R821
Adjust R821 to the response curve “A” shown in Figure 14.
3 Adjust Phase trans. T804
Adjust T804 to the response curve “B” shown in Figure 14.
4
Remove Oscilloscope to TP804.
SOUNDTRAPALIGNMENT
STEP
I
ADJUSTMENT
COMPONENT
PROCEDURE
1
Connect Oscilloscope to TP802.
Fine tune until sound appears in the chroma signal.
2
Adjust 5.5MHz Sound
Trap trans.
T207
Adjust the 5.5MHz sound trap (T207) for minimum sound in the
chroma signal.
CORRECT IN CORRECT
Response “A”
CORRECT IN CORRECT
Response “6”
Figure 14. H-l Delay Circuit Alignment

TROUBLE SHOOTING GUIDE
Methods of Checking
Repairs will be considerably simplified by careful observa-
tion of the defect and its location to a specific part of the
circuit. Once this has been done it can be said that 90%
of the repair has been completed.
To do this an understanding of the outline of the ICs used
in solid state colour T.V. will be of great assistance in
quickly diagnosing the cause of trouble.
When checking, the following procedure is recommended:-
1) Carefully note the symptoms of the trouble. Ensure
that the defect is in fact caused by the receiver and not
by a fault in transmission, by switching to alternative
channels.
2) If the fault is present on all channels locate the defective
circuit in the receiver.
3) Where the defective circuit has adjustable controls
ensure that these are correctly set. If adjustments have
no effect on the fault be sure to re-set to the original
positions.
4) Measure voltages and waveforms of the suspected circuit
block and, if defects are found, replace the transistors,
ICs or other components.
(a) Check the collector voltage and waveform of
transistors.
(b) Check voltage between base and emitter of
transistors. (Generally 0.3 - 1 v for silicon
transistors and 0.1
- 0.5 v for germanium tran-
sistors).
(c) Measure the terminal voltages and waveforms of
ICS.
(d) Check resistors, capacitors and coils.
Note: When removing components from the
PWB dis-
connect the leads by heating the soldered portions
with a soldering iron, removing surplus solder
with a desoldering tool.
PART
r==h
PWB
COPPER FOIL
- OESOLDERING TOOL
Melt the solder and suck it
up by the desoldering tool.
Figure 15.
PRECAUTIONS TO BE TAKEN DURING REPLAIR
In servicing, some of the methods used for valve systems
do not work on solid state colour T.V. receivers. Keep in
mind that:-
1) Transistors and KS MUST NOT be overloaded, even
momentarily.
In the case of valves, damage is rarely caused even if the
anodes and screens are severely overloaded, provided
that this condition is not maintained for very long.
Transistors and ICs, however, should not be subjected
to overload even for a moment.
Be sure to switch off the power source when removing
or soldering leads or measuring resistance.
2) Essential Conditions in Checking Transistors
The test and replacement of power transistors must be
carried out in such a way that the transistor is kept in
its heat-sink. Valve checking is simple but with tran-
sistors testing is complicated by the fact that screws and
solder must be removed. Never test a power transistor
which is not securely fixed in its heat-sink otherwise
damage will be caused by overheating as power tran-
sistors consume large current.
To check small transistors, remove as quickly as possible
with a soldering iron avoiding excessive heating of the
transistor.
3) Avoiding short-circuits
When checking voltages or waveforms take care not to
produce shortcircuits with the test probes or test clips
of the meter or oscilloscope.
During operation: -
DO NOT short the emitter resistor.
DO NOT short or open circuit the bias resistor.
DO NOT short the collector resistor.
DO NOT allow adjacent legs of ICs to come into contact
with each other.
4) Do Not Operate Vertical Output Circuit With Parts
Removed.
If the vertical output circuit is operated with parts
removed a large flyback pulse may be produced which
can cause short-circuting or deterioration of transistors.
5) In checking the horizontal deflection circuit, abnormal
oscillation such, as sparking the high voltage circuit and
stopping the oscillator circuit must be avoided.
If the high voltage circuit is checked by sparking the
driver or the input pulse is cut off abruptly with the
horizontal output circuit operated, the output transistor
may be damaged. The output transistor is designed to
withstand high voltages but if it is heated or subjected
to abnormal conditions for long periods the resistance
against voltages’ will be considerably reduced, and the
transistor may be damaged if subjected to an input
circuit shock (cutting off the input instantly) or output
circuit shock (sparking the high voltage circuit).
6) Others
Wires must be carefully arranged after check and repair.
(Be sure to connect them to the original places taking
care not to induce high voltages or other circuitry).
18

These notes may give the impression that the repair of
IC and transistorised sets is a complicated procedure.
,
However, no difficulties should be encountered provided
that it is remembered that extra care must be taken in
comparision to valve-operated receivers.
EXAMPLES OF DEFECTIVE PARTS
1) Transistors
(a) Short-circuit of connections . . . Continuity in
both forward and backward directions when
measured by an ohmmeter.
(b) Burn-out of connections (open) . . . No continuity
in both forward and backward directions when
measured by an ohmmeter.
(c) Deterioration of characteristics.
2) Capacitors
(a) Change of capacity
(b) No capacity (open)
(c) Defective insulation (leak)
(d) Short-circuit
3) Resistors
(a) Increase of resistance value
Generally, resistances tend to increase in value
during use. This often occurs in cases of higher
resistances than 1OOK ohms.
(b) Bum-out
Resistance value is extremely increased.
4) Coil, Transformers
(a) Burn-out
(b) Layer short - line short - iron core short . . . etc.
CHECKING OF TRANSISTORS BY OHMMETER
Transistors can be checked by measuring the forward
backward resistances between collector and base,
emitter and base.
and
and
Since the function of a diode exists between emitter and
base, collector and base, low and high resistances
are
indicated by polarity when measured with a test meter.
The former is the for.ward resistance and the latter is the
backward resistance.
Attention must be paid to the range of the ohmmeter.
In the case of an ordinary transistor, the range can be
found by X1000, but the range of a power transistor must
be reduced for the measurement. Alteration of resistance
values measured by tester.
(1) Short-circuit of connections . . . Both forward and
backward resistances become zero.
(2) Burn-out of connections (OPEN) . . . Both forward
and backward resistances become infinite.
(3) Deterioration of characteristic . . . Difference between
forward and backward becomes small.
Note: It is desirable to measure the transistor whilst
disconnected from the PWB.
R
I----- -----1
, :--,';-.C.L, ,
-----+A ‘d+----- R : LEAK RESJSTOR
I
1
LAYER SHORT
LAYER LEAK
-1 I
I
-_.- ----_- -I
SHORT
Figure 16
$6
LAYER SHORT
Figure 17
-4&k-
BURN-OUT
19

EXPLANATION OF CODES FOR RESISTOR AND CAPACITOR
RESISTOR
I
A, B
I
C
I
D
COLOR SIGNIFICANT FIGURES DECIMAL MULTIPLIER EXAMPLE
(POWER OF 10) TOLERANCE
(RESISTANCE)
II
II
I
I
0
loo
BROWN
I
1
I
10’
I
XlOfi
I
-
RED
I
2
I
102
I
XlOOR
I
-
ORANGE
3 103
Xl&!
-
YELLOW 4
lo4 XlOKfi
GREEN
5 lo5
XlOOKR
-
BLUE
6 10”
XlMa
-
VIOLET 7 10’ XlOMR
-
GRAY
I
8
I
lo8
I
XlOOMa
I
-
WHITE
I
9
I
lo9
I
XlOOOMfi
I
-
GOLD
-
SILVER
-
COLORLESS
EXAMPLE
A : RED
B : VIOLET
27 x lo3
C : ORANGE
= 27,OOOa
D : CX)LD 27Kfi2+5%
CAPACITOR
I I
I
(A)
CAPACITY
(B)
(0
TOLERANCE WITHSTAND VOLTAGE
A B
EXAMPLE
1RO 1PF G + 2% 1B
12v 3A 1KV
100 1OPF
J+,
5%
1E
25V 3D 2KV
101 1OOPF K +10% 1H
5ov 3F
3.15KV
102
1OOOPF M
+20% 2E
250V
3G 4KV
103 O.OljfF P +100-O%
2F 315v 2u
104 O.lpF S +150-O%
2H
5oov
Except for the T *200-O%
WITH UNDER LINE
above, the indica-
tion methode 2s
Z +80-20% WITHOUT UNDER LINE
25V or SOOV
,
direct indicated to Except for the above, the indication methode
as
capacity. direct indicated to withstand value.
A 8
2OOOPF f 5%
5ov
O.Ol@ + 10%
630V
20