Sharp DV-5145 User manual

SHARP SERVICE MANUAL
S85E7DV-51451
pE!
NEW COSMOS-3 CHASSIS
ARETUBE] ’
PAL SYSTEM
COLOUR TELEVISION
MODEL DV-5145
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.
7 CoNTENTS
ELECTRICAL SPECIFICATIONS
~
Page
.ELECTRICAL SPECIFICATIONS .............
1
.IMPORTANT SERVICE NOTES .............
2
l DESCRIPTION OF NEW CIRCUIT. .......... 3
. SERVICE ADJUSTMENT
..................
. TROUBLE SHOOTING TABLE
..............
,;
l CHASSIS LAYOUT DIAGRAM
..............
15
. PRINTED WIRING BOARD ASSEMBLIES
......
17
l BLOCK DIAGRAMS
.....................
19
. SCHEMATIC DIAGRAMS AND WAVEFORMS
... 21
l REPLACEMENT PARTS LIST.
..............
27
Aerial Input Impedance ..........
75 ohm unbalanced
Convergence ..............
Self Converging System
Focus
............... High Bi-potential electrostatic
Audio Power Output Rating
..............
2W max.
Intermediate Frequencies
Picture IF Frequency
..............36.875MHz
Sound Carrier Trap ................31.375MHz
Adjacent Sound Carrier Trap
.........38.375MHz
Powerlnput ...................
.240VAC50Hz
Power Consumption
......................80
W
Speaker
.......... 5 cm x 9 cm Oval Dynamic x 1 pc.
Sweep Deflection
.....................
Magnetic
Tuning Ranges
............VHF
Channels 9 thru 11
UHF Channels 28 thru 63
Specifications are subject to change without prior notice.
-.
SHARP CORPORATION OF AUSTRALIA PlY LTD.
Incorporated in Victoria
64-72 Seville St., Fairfield. N.S.W. 2165, Australia
Tel: [phone]

IMPORTANT SERVICE NOTES
Maintenance and repair of this receiver
should be done by qualified
service personnel only.
SERVICING OF HIGH VOLTAGE SYSTEM AND PICTURE
TUBE
When servicing the high voltage system, remove static charge from it by
connecting a 10k ohm Resistor in series with an insulated wire (such
as a test probe) between picture tube tag and 2nd 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 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 pro-
duce potentially hazardous rediation with prolonged exposure at close
range, the following precautions should be observed:
1: When repairing the circuit, be sure not to increase the high voltage to
more the 28kV, (at beam 1 .l mA), for the set.
2. To keep the set in a normal operation, be sure to make it function
on 25.0kV + 1.5 kV (at beam 1.2 mA) in the case of the set. The set
has been factory-adjusted to the above-mentioned high voltage.
’
. .
If there is a possibility that the high voltage fluctuates as a result
of the repairs, never forget to check for such high voltage after
the work.
3. 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 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 fishpapers, cabinet backs, adjustment and compartment
covers or shields, isolation resistor-capacity networks, mechinical
insulators etc.
2

DESCRIPTION OF NEW CIRCUIT
ICl 01 RH-iX0605CEZZ (MICRO PROCESSOR)
1. Outline of IClOl
(1) IClOl consists of ROM (1270 words x 8 bits) and
RAM (32 words x 4 bits).
(2) Presetting of the described stations allowed by
operating the TUNING (+)I(-) keys and FINE TUN-
ING (+)/(-) keys.
(3) Tuning voltage available in 16,384 steps due to D/A
output.
(4) Channel number display by 2-digit 7-segment LED.
(5) Display of 11 ch. to 16ch. is allowed by using “10”
key in combination with one of “1” to “6” keys.
2. Pins arrangement of IClOl and its external connec-
tion
3. Key matrix
Table l-l
Eo
El
E2
E3
I
Fo / F, / F2
’ :
F3 j F4
I
10 i
I
4 / 8 ’
/ FT(+)
1
5 9
!
1 FT(-)
6 !
2
’ T(+)
I
3 / 7 //
T(-)
F”
ICI101
rt. ~~~-wlOUTP"T
J
VI)‘ - - 22 t-4
21 F5
4L
~+$&-j E.
vss *+5v
CLOCK vGG -- -30~
20 Fe
VHF
’ ’
::&f”’
lc3 IL,
BAND OUTPl
JT
c AFT MUTE
- SOUND MUTE
Figure l-l
4. Sweeping speed of tuning key
Table l-3
Tyew /
I
TUNING (+)I(-)
FINE TUNING (+)I(-)
/
/ Resolution Sweeping
speed , Reso,ution Sweeping speed
within a band 1
within a band
3 min
VHF-L
10sec /,
VHF-H
8116,384 20 set
! 2/16,384 I
6 min
UHF 1
/
I
/
40 set I
12 min
Table 1-2
1
I
I
C
E/ E
1
1
I
E2 I
-
I
3

5. Key operation at each mode
Key
1 - 10
T(+)
V-1
F-n+)
m-1
10
Normal mode Preset mode
When one of “1” to “10” keys is pushed, the data
of the corresponding position is read out of the
memory so that the desired station is tuned in.
The currently selected station is stored as lastly
selected position in the memory.
When one of “1 fl to “10” keys is pushed, the
corresponding position is displayed on LED. But
the data in the memory remains as it is.
Not operative.
When FT(+) or FT(-) key is pushed, APT is turned
off and the unit performs a sweeping of tuning
voltage. And when the key is touched off, the data
of tuning voltage is written in the memory.
Within 2 seconds after “10” key has been pushed,
when one of “I” to “6” keys is pushed, one of
“11“ to “16” positions is displayed and tuned in;
when one of “7” to “IO” keys is, however,
pushed, one of “7” to “10” positions is displayed
and tuned in.
t
1
When T(+) or T(- key is pushed, the unit performs
a sweeping of tuning voltage. And when the key is
touched off, the data of tuning voltage is written in
the memory.
When FT(+) or FT(-) key is pushed, the unit
performs a sweeping of tuning voltage. And when
the key is touched off, the data of tuning voltage is
written in the memon/.
Within 2 seconds after “10” key has been pushed,
when one of “1” to “6” keys is pushed, one of
“11” to “16” positions is displayed but not tuned
in since the data in the memory is kept as it is.
6. Tuning operation
When one of “1” to “IO” keys is pushed in the normal
mode, the corresponding data is read out of the EA
ROM so that the band output and tuning voltage are set
up to allow the unit to tune in the desired station. Then
the currently tuned in station is stored as a lastly
selected position in the specified address of EA ROM.
During the tuning operation, AFT output and MUTE
output are caused in the following timing.
AFT output
(AI) 11
I
I
MUTE output *
I
I
MO)
Writing /Reading
l
of last
pf tuninq
I
I
data voltage
i” ’
ata
Ii
1
II
I
1 50-60
i’-
50 msec
16 msec 1
200 msec msec
‘1
0 AFT turns on when AFI output is at High level.
l Muting occurs when MUTE output is at High level.
Figure 1-2

IC203 RH-iXO6OlCEZZ (PIF/SIF/JUNGLE)
1. Outline of IC203
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
PIF amplifier of sync demodulator type
Negative modulation AGC detector circuit
Tuner RF AGUIF AGC
AFC circuit
Video preamplifier
Sound IF amplifier and demodulator circuit
Horizontal oscillator drive circuit/horizontal oscilla-
tor/horizontal output circuit
Audio preamplifier
Horizontal sync circuit with two control loops
Sawtooth wave generator/vertical sync circuit with
50Hz/60Hz automatic verfical amplitude control cir-
cuit
Sand castle pulse generator circuit
2. Pins arrangement
AGC TAKEOVER
RAMP GENERATOR
VERTICAL DRIVE
VERTICAL FEEDBACK
TUNER AGC
GROUND
SUPPLY (+B)
IF INPUT
IF INPUT
DECOUPLING CAPACITOR
VOLUME CONTROL
AUDIO OUTPUT
SOUND DEMODULATOR
SOUND IF DECOUPLING
Figure 2-l.
3. Function
PHASE-U DETECTOR (APC)
SAND CASTLE
HORIZONTAL DRIVE
SYNCSEPARATOR
FREQUENCY CONTROL
HORIZONTAL OSCILLATOR
COINCIDENCE DETECTOR
SYNC DEMODULATOR
SYNC DEMODULATOR
AGC DETECTOR
AFT
VIDEO OUTPUT
GROUND
SOUND IF INPUT
Pin 0: AGC cut-in level
Pin 0: Generation of vertical sawtooth wave
Pin 0: Vertical drive output
Pin @: Vertical feedback circuit (correction of vertical
linearity and size)
Pin 0: Tuner RF AGC
Pin @: PIF ground
Pin 0: Power supply + B (1 IV)
Pin @: IF input
Pin @: IF input
Pin @I: IF decoupling capacitor
Pin 0: Sound volume control
Pin 0: Audio output
Pin 0: SIF detection
Pin @: SIF decoupling capacitor
Pin 0: SIF input
Pin @: SIF.horizontal oscillator ground
Pin 0: Video output
Pin @: AFT
Pin @: AGC detector
Pin @I: IF sync detector circuit
Pin @I: IF sync detector circuit
Pin @: Sync circuit
Pin @I:
Pin @:
Pin @:
Pin @:
Pin @:
I
1 I
I 1
II
f 1
/
$/ith no;
*
/ -I
Fast’ ’ Slow 1
Field intensity
Sync
stgnal
flow ’I
-
’ Fast -cI Slow y
Figure 2-2.
Horizontal oscillator circuit
AFC circuit (1st control loop for frequency con-
trol)
Sync separator circuit (to decide sync separa-
tion level)
Horizontal drive output circuit (also works as
horizontal drive pulse input circuit.)
Sand castle output
Resulted from
FBT pulse and
sync signal made
together
Figure 2-3.
l This output is used for the following functions; @ Burst
samPling. @ Blanking, @ DC restoration and @ Flip-flop
Pin @: Phase-II detector (APC circuit 2nd control loop
for phase control)
5

IC501 RH-iX0640CEZZ (VERTICAL OUTPUT)
1. Outline of IC501
(I) High output
(2) Lower power consumption thanks to the built-in
4. Circuitry bhaviors
(I) The vertical oscillation signal entering pin @of
pump up circuit
(3) The number of external parts reduced
2. Pins arrangement
,
VERTICAL
DRIVE
4 4
5
F”
K+ -
IAJX
-s
>o,
I 2
1
--d
1
-io-o~o?j,+j-
g .k 5 - .g .g 2 3
0
s
a
-2s s
sf -
+ 5
2
;: -
c”
tij
>
0
E
P
3
iG
2
& .z
5
.z
r
%a
m
;
E f
F
8 o>
5:
3 z
0 2
lC501 activates the vertical drive circuit and vertical
output circuit.
(2
) When the vertical drive circuit and vertical output
circuit are in action, it is only in the flyback period
that the booster (pump up) circuit is allowed to
operate to provide the voltage about twice Vcc.
(3
I) The design that the supply voltage is boosted only
in the flyback period results in remarkably reduced
power consumption.
(4) In the c onventional
SRPP output circuit, Vcc must
be supplied until the flyback pulse voltage reaches
its highest value. In this circuit, however, it is
sufficient to use about half of Vcc for the circuitry
operation.
Figure 3-1.
3. Block diagram and application
DC. NF B
0
D.Y
+BI
AC. NF B
JVP-P
INPUT
Figure 3-2.
6

IC701 RH-iX0689CEZZ (POWER REGULATOR)
1. Oscillation principle
(1) When the power switch is turned on, a current IsI is
applied to the base of TR5.
(2) Then, a current lc=hfe.ls, is applied to the collector
of TR5.
(3) The current lc available at the collector of TR5
causes a voltage (feedback voltage of the same
polarity) at T701.
(4) As the feedback voltage is given, a current IF
available at pin @of l701 is allowed to run through
0705 and R711 and enter the base of TR5. When the
feedback voltage increases to more than the speci-
fied level, TR5 starts its oscillation.
(5) As the voltage at the collector of TR5 increases to
its saturation point, a reverse bias is applied to its
base to interrupt the oscillation.
(6) When the oscillation of TR5 is stopped, the energy
stored in T701 is discharged through the secondary
winding N4.
(7) Then there is caused a voltage (of the reverse
polarity) at Nl and N2 to turn on TR5 again.
Thereafter, the process is repeated for TR5 to
perform the oscillation continuously.
2. Operational principle of error amplifier
(1) The voltage which is induced at N3 winding is DC
rectified to produce a control voltage (between pins
@and 0).
The control voltage available at N3 is highly correla-
tive with the output voltage of N4 because both N3
and N4 are electrically coupled with each other.
(2) Variation of the control voltage is detected by TRl
and ZDl.
(3) As the detec e voltage increases, it is amplified by
t d
TR2 and TR3 so that the current at the base of TR5
is bypassed.
(4) Then the current at the collector of TR5 is limited to
the smallest.
(5) Accordingly, the pulse width is controlled to decide
the duration where TR5 is kept turned on.
3. Over-current protector circuit
(1) An over-current 12 is applied to TR4. With TR4
turned on, the current at the base of TR5 is so
reduced that TR5 will eventually stop the oscillation.
(2) With the over-current applied to TR5, there
is caused a
voltage between pins@and@of T701 and this voltage
is supplied via 0705 and R711 to the base of TR5, so
that Vin DC is allowed to run in C708 and R708 to
enter the base of TR5.
In the actual circuitry, however,
this current Vin DC can’t reach the base of TR5 because
that C708 has already been charged up.
h31
0
11
N.C
R3 =
* TRl
1 1
u
Figure 4.
D2
7
+B

IC801 RH-iX0603CEZZ (VIDEO/CHROMA)
1. Outline of MO1
1) PAL signal demodulation and R/G/B matrix output
2) White peak limiter control circuit 3) R/G/B mixing circuit included
4) Sand castle pulse processor
2. Pins arrangement
+12V POWER SUPPLY
CONTROL VOLTAGE FOR INDENTIFICATION
CHROMINANCE INPUT
REFERENCE VOLTAGE A.C.C DETECTOR
CONTROL VOLTAGE A.C.C
SATURATION CONTROL
CONTRAST CONTROL
SANDCASTLE AND FIELD BLANKING INPUT
VIDEO DATA SWITCHING
LUMINANCE SIGNAL INPUT
BRIGHTNESS CONTROL
RED OUTPUT
(INPUT OF EXTERNAL RED)
GREEN OUTPUT
Figure 5.
3. Circuitry behaviors
Pin 0: 12V power supply
Pin 0: Generation of ACC detector control voltage
(generation of killer on/off control voltage)
Pin 0: Chroma input
Pin @: Reference voltage for ACC detector
Pin 0: ACC control voltage
The peak detector ACC works to detect the
voltage which is proportional to the burst signal
level.
Pin @: Colour saturation control
Pin 0: Contrast control
Pin @: Sand castle puise input
The sand castle pulse is divided into two pulses;
the first pulse is set at 1.5V DC and used for
blanking of the R/G/B output signal, and the
second pulse is set at 7.OV DC and used for
black level clamping and burst keying.
Pin @: Video data switching
Switching between R/G/B input and video input
is performed: R/G/B input at High level, video
input at Low level.
Pin @I: Luminance signal input
Pin 0: Brightness control
Pin 0: Red output
Pin 8: Input of external red
Pin @I: Green output
Pin @: Input of external green
Pin @I: Blue output
Pin 0: Input of external blue
Pin 0:
Pin @I:
Pin @:
Black level clamping (only with R/G/B signal
input) to provide the same black level in both
R/G/B input mode and video mode.
Pin 0: B-Y input demodulator
Pin @I: R-Y input demodulator
Pin @: Burst phase detector output
Pin @:
1
These are used to compare the burst gate
signal with the reference signal coming from
the reference oscillator, so that the resultant
signal in applied to the external low pass filter
(R804, C818) to produce a phase control vol-
tage.
Pin @
Pin @:
1
Reference oscillator
8.86 MHz of the reference oscillator is halved
to be 4.43 MHz (this makes esier a 90” phase
shift operation).
Pin @I: Ground
) OUTPUT OF THE CHROMA AMPLIFIER
I GROUND
REFERENCE OSCILLATOR
I REFERENCE OSCILLATOR
BURST PHASE DETECTOR OUTPUT
’ BURST PHASE DETECTOR OUTPUT
R-Y INPUT DEMODULATOR
1 B-Y INPUT DEMODULATOR
BLACK LEVEL CLAMP CAPACITOR
BLACK LEVEL CLAMP CAPACITOR
I BLACK LEVEL CLAMP CAPACITOR
(INPUT OF EXTERNAL BLUE)
) BLUE OUTPUT
) (INPUT OF EXTERNAL GREEN)
Pin @I: Chroma output

SERVICE ADJUSTMENT
Precautions:
How to prevent ICs from damages due to static elec-
tricity
1.
2.
3.
4
When replacing or handling the IC, be sure to put on
your wrist a metal ring (earth ring) that is connected
to ground.
+ Avoid touching the IC directly by hand as much as
possible.
For the soldering iron and other jigs in use, be sure
to connect them to ground so that their potential is
the same as that of the PWB and/or IC.
The PWB cannot be connected to ground in some
condition although you attempt to attach the IC to
that PWB. In this case, be sure to keep the PWB at the
same potential as ground by touching it by your
hand on which a metal ring is put.
When handling the IC, it is recommended for you to
wear such clothes as not causing static electricity;
the ones of wool, silk or synthetic fiber should be
avoided. This is important in particular when hand-
ling the IC in a dry environment.
Overall waveform
1.
2.
3.
4.
Receive 10 ch. signal.
Connect the sweep output to the tuner TP (test point)
through the specified jig.
Connect the response lead to TP403.
l Oscilloscope range: 0.2V/cm
Connect a resistor (100 ohms) to both ends of R229
(10 kohms) and short C,.
Note: Keep the lead of the 100 ohm resistor as short
as possible.
A Shorting __
L --= J T201 (P-DET)
5. Apply DC voltage (about 5V) TP207 (IF-AGC) and
adjust so that the output waveform on oscilloscope is
at O.GVp-p.
Note: The voltage applied to TP207 should not ex-
ceed 7V in any case.
6. Check that the overall waveform is within the speci-
fied range shown below.
‘\il’
C: -8 f 2.5 dB
P: -6 ?I 2.5 dB
If the waveform is out of the specified range, adjust it by
using the IF transformer (IFT) on the tuner.
n Location of TP and IFT of the tuner:
Adjustment of AFT: T201
1.
2.
3.
4.
5.
6,
Receive luminance-order colour bar signal.
Adjust R225 (RF-AGC control) so that normal picture
appears on TV screen.
(Set the band switch at NORMAL position.)
Connect 36.875 MHz oscillator to TP204 across a
capacitor of 1 pF.
Connect oscilloscope to TP403.
l Oscilloscope range: 0.5 V/cm AC
l Sync operation: Horizontal
Adjust the oscillator’s output so that signal beating is
observed on oscilloscope.
Adjust the tuning control to have zero beating on
oscilloscope as shown in the figure below.
(Set the band switch at VHF position.)
6
Zero beating
7. Set the band switch at NORMAL position and adjust
T201 to make zero the beating.
r
[1
Adjusting point
T201
9

RF AGC cut-in adjustment: RZ25
1. Receive 10 ch. signal.
2. Set the signal input level at 52 +1 dBu.
3. Connect CR oscillator to TP202 across a capacitor of
10 uF/lGV: This capacitor is to cut off DC supply.
I aIsl2.L ToTP202
c
r -,
r.
I
- To TP201
l Oscillation frequency: 1 kHz sine wave
l Output voltage : 0.1 vp-p
(when connected to TP202)
4. Adjust R225 so that 1 kHz signal disappears from TV
screen.
5. Set the signal input level at 52+3 dBp and check that
1 kHz signal appears on TV screen.
If 1 kHz signal does not appear, set the input signal
level at 52 dBu again and follow the procedure in
step 4 again.
Sound detector coil adjustment: T301
1. Connect signal generator’s output to TP301.
l Generator’s central frequency: 5.5 MHz
l Modulation: No modulation
l Generator output: 80 dBu (terminated with 50R)
2. Connect DC voltmeter to TP302.
3. Adjust sound volume to minimum and measure the
voltage then available at TP302; this voltage (about
2.5V) should be regarded as a reference voltage.
4. Adjust sound volume to maximum and turn the core
of T301 (sound detector coil) until DC voltmeter reads
the reference voltage obtained in step 3 above.
Horizontal frequency adjustment: R605
1. Receive monoscope pattern signal.
2. Short TP601 and TP602 (at both ends of R606).
3. Adjust R605 to obtain good horizontal sync on TV
screen.
4. Remove the short-circuit between TP601 and TP602.
Sub-brightness adjustment: R415
1. Short TP401 and TP402.
2. Set each control as follows:
l Screen control: at MIN position
l G-bias control (R853-A): at MIN position
l B-bias control (R853-B): at MIN position
l R-bias control (R869): at MIN position
l G-drive control (R854-A): at CENTER position
l B-drive control (R854-B): at CENTER position
l Contrast control (R 1110) : at M IN position
l Brightness control (Rl 110): at CENTER position
l Picture control (R 1110) : at CENTER position
l Colour control (Rl 110) : at MIN position.
3. Receive monoscope pattern signal.
4. Connect oscilloscope to TP850 (with L2 connected to
ground)
5. Adjust R415 (sub-brightness control) so that the
output waveform on oscilloscope is at 15 Vp-p.
6. Remove the short-circuit between TP401 and TP402.
Background adjustment:
R854-A; G-drive control, R853-A; G-bias control
R854-B; B-drive control, R853-B; B-bias control
Screen control, R869; R-bias control
1. Receive monoscope pattern signal.
2. Set each control as follows:
l Brightness control: at CENTER position
l Contrast control: at MIN position
l Screen control: at MIN position
l G-, B-drive controls: at CENTER position
l R-, G-, B-bias controls: at MIN position
3. Short TP401 and TP402.
4. Turn screen control until horizontal raster slightly
appears on TV screen.
5. One of the colours (R, G and B) appears first as
screen control is turned. So touching off the bias
control belonging to the first colour, adjust the other
controls as follows to make white the horizontal
raster.
I
First /
colour 1
Bias controls to be next turned.
I
Red
I
R853-A, R853-B
I
Green 1
R869, R853-B
I
Blue 1
R869,
B853-A
6. Turn screen control until the raster disappears and
stop it.
7. Remove the short-circuit between TP401 and TP402.
8. Set contrast control at MAX position.
10

9. Adjust each drive control for good white balance.
l Colour temperature: 7300°K
I
x = 0.303
y = 0.310
1
10. Adjust brightness control and contrast control to
obtain a dark picture, then follow the procedure in
step 5 to make white the raster.
11. Again brighten the picture and adjust each drive
control for good white balance as in step 9 above.
1H delay line adjustment: R806, T802
1.
2.
3.
4.
5.
6.
Receive colour bar signal.
Set each control as follows:
l Brightness control: at CENTER position
l Colour control: at CENTER position
Connect oscilloscope to TP851 (collector of Q852) on
CRT PWB (with L2 grounded).
l Sync operation: Horizontal
Note: The probe of oscilloscope in use must be of a low
capacitance (2 to 3 pF).
Adjust contrast control so that the top of output
waveform on oscilloscope won’t be depressed.
Short TP401 and TP402.
Adjust R806 and T802 so that the parts “A” and “B”
shown below become minimum respectively.
waveform after
adjustment
Horizontal size adjustment: S601
1. Receive monoscope pattern signal.
2. If the horizontal size is at less than 7% of overscan-
ning, insert the socket into the opening (2) of SSOl.
(1) (2)
H-SIZE
Horizontal center adjustment: R618
1. Adjust R618 to have proper horizontal center.
Vertical size adjustment: R508
1. Adjust R508 to have the vertical size be at 8% of
overscanning.
Vertical center adjustment: S501
1. If the vertical center of picture is 5 mm higher than
the geometrical center of CRT, set S501 at “down”
position.
If it is 5 mm lower than the geometrical center of
CRT, set S501 at “up” position.
D
+5 mm or
more
$
t
-5 mm or
more
- downh
APC adjustment: R802
Protector check
1. Receive luminance-order colour bar signal.
2. Short TP803 and TP804, and also TP801 and TP802.
4. Remove the short-circuits between TP803 and T804,
3. Adjust R802 so that barber pole pattern appears on
and between TP801 and TP802.
lV screen.
1. Apply DC 22V to TP703 (0 side of C728), and check
that the protector remains inoperative.
3. Connect a resistor of 10 kohms between TP704 (base
2. Apply DC 28V to TP703, and check that the protector
of Q703) and ground, and check that the protector
gets operative.
gets operative.
Sub colour adjustment: R817 Sub-sound adjustment: R4008
1. Receive luminance-order colour bar signal.
l Signal input level: 80 dBp _+ 5 dBp
2. Set each control as follows:
l Brightness control: at CENTER position
l Contrast control: at MAX position
l Colour control: at CENTER position
l Picture tone control: at CENTER position
3. Connect oscilloscope to TP850 (collector of Q850)
(with L2 grounded).
4. Adjust R817 (sub colour control) so that the white
output (75%) and red output will have the same level.
11
1. Receive an audio signal of 400 Hz and 30% modulation.
2. Connect a dummy resistor of 8ohms to the speaker
terminal.
3. Set sound volume (R 1111) at MAX position.
4. Connect an effective-value voltmeter to the dummy
resistor. .
5. Adjust R4008 (Sub-sound control) so that the output
voltage of the dummy resistor is 3.35 Vms.

TROUBLE SHOOTING TABLE
I
NO RASTER
I
No
I
15V line
is normal?
No
1
I
Check D701 - 704,
D706, D708, T701,
L706, IC701 and
F7001
115V line
is normal?
I
25V line No
Yes
is normal?
_ . )‘r’<;>~’
Check Q702,
.,
Check D502, 0711,
1
R741, T701 and
115 V line.
R725
Waveform at
base of 0601
No
1
4
Check R724,
I
YCS
I
Q701, Q703,
D710 and
D716.
I
Check IC203.
I
I
No
,
Check R617
and T602.
Yes
c
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+
((HI-4 terminal)
No
Check D709
and R732.
@;gi;;;&>
No I
Waveform at
YCS
TP403 is
normal?
No I
I 1 I
)I
Check IC203, Q401
and A/V Unit.
Check IC801
12

I
NO COLOUR
I
I
No
I
YOS
Check IC801.
I
I I
No
I
I
1
I
Check RlllOand
R817.
I
I
Check IC801.
I
NO PICTURE
.
I
YIK
Check
IC801,
RlOOl,
Q40 1
and
Video
Switch
Unit.
I
Check Q850,0851
and Q852.
IC203,
Q203
and
Tuner.
13

Waveform at
No
Check IC203.
No
,
w
w
1
@c,k IC501 andCheck L501.
I.
I
NO SOUND
Yes
Check IC201,
0301 and IClOl.
Waveform at
Yes
c 4
No
I,
Check IC301.
1 1
.
.
I
Check SP301,
J3001 and L301.
I
14

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