Sanyo C25PP86N Service Manual
SA\j411!Y
SERVICE MANUAL Colour Television
Specifications
FILE NO.
Model”No. C25PP86N
(New Zealand)
Service Ref. No. C25PP86N- 00
.
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Power Source .................... AC 220-240 Volts, 50 Hz.
Colour System ...................
PAL (AV INPUT: PAL/NTSC/NTSC4.43/PAL- 60Hz)
L
Television System .............
B/G
Channel Coverage ............. VHF: 1-11
UHF: 21-69
CATV: S1 - S41 , X. Y, Z, Z+l , Z+2
Video IF
.............................
38.9 MHz
Sound IF............................ 33.4 MHz
Aerial Input Impedance ...... 75 S2
Ext. Terminals ....................
AV inputs:
Video inputs: Phono jack x 2
Audio inputs: Phono jack(R/L) x 2
AV outputs:
Video outputs: Phono jack x 1
Audio outputs: Phono jack(R/L) x 1
Headphone Jack: Mini. Stereo Jack x 1
Sound Output (Music) ........ 10W+1OW
Dimensions
........................
616(W)x530(H)x458.5 (D)mm
Weight(approx.) ................. 29Kg
Product Code: 111335319
Original Version
Chassis Series: AAl -A
Give complete “SERVICE REF. No.” for parts
order or servicing. It is shown on the rating plate
at the cabinet back of the unit.
-
This T.V. receiver will not work properly in
foreign countries where the television trans -
mission system and power source differ from the
Refer to “T1520004” Training Manual
for this model.
I I
Specifications subject to change without notice.
L
F6WZ
REFERENCE NO. SM 520248
I
Alol
TUNER
NICAM
DECODER
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TEXT DECODER
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1
SCL %
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SDA L
1
* SDA
Digital Control
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Vcc
1
Band Switch
.. . . .. .. .. .. .. .. .. .. ... . ..
1
1
43, 44
;3:Volume, 4: Co10ur, ;
I
3-8 +
5: Bright, 6: Contrast, :
~
10
;7: Sharpness, 8: TINT:
9
. . . .. .. .. .. .. .. .. .. .. .. ..4
: Rout 49
8
0
~ G out
n
m
~ B out
R out
OSD
[
~ G out
m
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~ B out
X180 SAW I
111-‘‘
IC2B0
SECAM
R-YuJl‘:
Iclol
+
‘-------r----:
HV
%
IC1103
SOUND
IC181
CONTROLLER
Video
I
lFjCOLOUR/
SIF ~ “2 h
16
DEFLECTION
IC270
Q21OI
— 2
21
— SOA
lH DELAY
Q211/Q212
\\\
SCART WI
19 —
SCL
IF in
4645
~ ,F ,“ B-YUII 31
14
w
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CRT
14
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B-Y in
6
R-Yti 30
; R-Y in
24 ‘h B-Y III :8
B-Y out
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R-Y o;t
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5
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22
08:
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SIFM
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27
RGB
out
T471 FBT
SCARTWI
Audio(UR) out@
\.
1
7
Exlwnd CVSS h
* 15
Q431
/$
NH -
Drive
Q432
Hcul 37
H-OUT
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CVBS In
13
=;:
Audio(L/R)in ~
2/1 2
. . .. . . . . . .
Wad Veflco 43
14/
IC451
=
3
15 ‘
Vert. Output
4
Deflection
1/13
4
Yoke
2
—
IC801
AV SWITCH
~ 3
~ Filter
H
~
Speakers
T501
POWER
TRANS
------
‘-----------:TRANS. ;-----------------------:
Headphone Jack
............................
..........................
Block Diagram (Formulti-standardModel)
.
L
.
,
.............................................
ICI 01 (TDA8362
El--d-+
NTSC
Band Limited
-J
Fin
V in
TvOut
SECAM
REF,
>IFin
CHROMA ID
TV ID,
(TIME BASE;
13
4
1
7
32
—
26
—
A
gt+
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......
gg:~~
.........-........
+~
+~
Zuy
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ti
*’
------
6.5MHz Filter
l’+%
Sll
(Q156)
F-----
6.OMHZFilter
~%
Slo
(Q155)
------
5.5MHz Filter
~%
S9
(Q154)
......
0%
SIF Filter
(Q153)
1-7==%
lzx$
S3 Sound Cam.er Trap
D121)
i
5.516.016.5MHz Trap
P
+----:
P%iE!5
10,
......
j (Q2%) ~
............
................................................
IC701 (CPU) !
j,;
SECAM 40--:
~ C ID.
~ TVID.
4.5 MHZ ?.!. .. . .. .. .. . ....+
5.5 MHZ :*----------.: :
6.OMHZ 3~------0 ~ ;
42 4.43 MHZ
.. .. .
:::
~,5MHz 36-, : : :
:::
::::
.-~3 3.58 MHZ
::, :
::
::
V-SYNC.
::
::
2
::
::
::::
V-SYNC. Pulse
:::
(for O.S.D.)
:::
:::
...................................:,:
::
::
::
::
:::
:::
......................................... .
::
::
::
::
::
::
............................................. :
...................................................
L
–3–
Circuit Description
1. POWER SUPPLY
The power supply circuit of the AAl - A chassis is
comprises a primary rectifier smoothing circuit, an
oscillation circuit, a control circuit and an output rectifier
circuit.
The AC input voltage is rectified at the double or full-wave
rectifier smoothing circuit, and an unstable DC voltage is
generated at both terminals of the smoothing capacitor
C307.
The double or full-wave rectifier circuit is build by
switching the triac on or off in IC501 <STR81 145A>. This
voltage is supplied to the oscillation circuit, which is
composed of a blocking oscillator circuit that switches the
switching transistor Q313 ON and OFF.
A square-wave oscillation is generated in the input
winding according to operation of the control circuit. A
quare-wave with amplitude dependent on the turns ratio of
the input and output windings is obtained in the output
winding. This is rectified in the output rectifier circuit, and
the desired DC voltage is produced.
2.
IF& DEFLECTION (TDA8361/8362)
The IF output signal from the tuner passes through the
SAW filter, and it is input to pins
45 and 46 of ICI 01.
Within the IC, the IF signal passes through the IF
amplifier,
video detection and video amplifier circuits, and
is outputted from pin 7 as a composite video signal. In the
monaural model, this composite video signal passes
through the 5.5 MHz(B/G) / 6.OMHZ(I) / 6.5 MHz(D/K) /
4.5 MHz(M) sound bandpass filtering circuit, and it is
inputted into pin5 of IC101. In the stereo model, the SIF
signal is supplied from pin
14 of IC181 cTDA2546A> to
pin 5 of ICI 01 through the sound bandpass circuit for
modulation of the main carrier. In the IC101, this sound IF
signal passes through the SIF amplifier, FM detector,
external audio switch and audio output circuit, and it is
then outputted from pin 50 as audio drive signal (Monaural
model). In the stereo model, the main audio signal is fed
from pinl to the stereo controller IC (MC44131 PB).
The video signals applied to pins 13 or 15 are separated
into vertical - and horizontal - sync. signals respectively by
the sync. separator in the IC.
The horizontal oscillator requires no external components
and is fully integrated. This oscillator is always running
when the start - pin 36 is supplied with 8V, and the
horizontal drive signal is outputted from pin 37. VR401 is
used for horizontal centring adjustment.
The separated vertical sync. signal from the sync.
separation circuit passes through the vertical - separation
circuit, and is applied to trigger divider circuit.
The horizontal oscillation pulse and vertical sync. pulse
are monitored by the trigger divider circuit to select either
the 50Hz or 60Hz system, and automatically adjust the
vertical amplitude.
The output signal from the trigger divider triggers the
vertical oscillator
circuit
whose
external timing –
components consist of R402, C401 to pin 42, and the
vertical ramp signal is outputted from pin 43. VR451 is for
controlling the amount of AC feedback applied to pin 41
for adjustment of the vertical amplitude.
3. VIDEO CHROMA (TDA8361/8362)
The composite video signal output from the pin 7ofIC101,
passes through Q122, and the sound traps Xl 24, X125,
X126, X127 to reject the sound carrier components, is
then supplied to pin 13 through the equalizing circuit
consisting of Q135, Q132 and Q1 34. The external video
signal from SCART or other AV terminals is supplied to
pin 15.
The video signal input to pin 13 or pin 15 is separated into
luminance (Y) signal and chroma signal in IC101. These
pins are also common to the H/V- sync. separation circuit _,
input already described.
The peaking of Y signal is adjusted by DC voltage on pin
14.(’’SHARPNESS” control)
The chroma signal is divided into R-Y and B-Y chroma
signals, which are demodulated and output from pin 30 (R
- Y) and pin 31 (B - Y). These chroma signals pass
through the 1H delay line circuit (IC270), and are re inputted at pin 29 (R-Y) and pin 28 (B- Y). These R- Y/BY signals pass through the RGB matrix circuit and the
RGB selector circuit of ICI 01. The internal RGB signals
are generated in the RGB matrix circuit and the RGB
selector, consisting of linear amplifiers, clamps and
selects either the internal RGB signals or the external
RGB signals input from pin 22 (R) , pin 23 (G), pin 24 (B).
Selection is controlled by the voltage at the RGB switch
control (pin
21) and mixed RGB modes are possible since
the RGB switching is fast.
The RGB switch also functions as a fast blanking pin by
blanking the RGB output stages; here internal and external RGB signals are overruled.
The RGB signals for the on - screen display are
superimposed onto the selected RGB signals at the base
of transistors Q21 O, Q211 and Q212 respectively.
The saturation of colour gain is controlled by the DC
voltage of pin 26. (“COLOUR” control)
The contrast control voltage present at pin 25, controls the
RGB signal gain, and the brightness control voltage
present at pin 17, controls DC level of RGB signals.
The RGB signals are finally buffered before being
presented to the RGB output pins [pin 20 (R),
pin 19 (G),
pin 18 (B)].
–4–
Circuit Description
.-
4. AUDIO OUTPUT
4-1 (AN5265)-Monaural model
The audio signal output from pin 50ofIC101 is inputted to
pin 2 of ICI 71 and passes through the pre - amplifier
circuit and the drive circuit into the audio amplifier. The
audio amplifier is the SEPP (Single - Ended Push Pull)
type and the output from pin 8 drives the speaker directly.
4-2 (TDA7263M)-Stereo model
The audio signals output from pins 17 and 18 of
IC1 101 (MC44131 PB) are inputted to pins 1(Left) and
5( Right) of IC1 102 and passes through the pre - amplifier
circuit and drive circuit, after which it is input to the audio
amplifier. The audio amplifier is the SEPP (single-ended,
push - pull) OTL type and the outputs
from pins 8(Right)
and 10(Left) drive the speakers directly.
5. VERTICAL OUTPUT
L
An LA7833 is used for the vertical output circuit in this
chassis. The vertical ramp signal from pin 43 of IC101 is
inputted to pin 4 of IC451. This ramp drives IC451, and
vertical scanning is performed. In the first half of scanning
a deflecting current is outputted from pin 2 and passes
through the following path:
VCC(B4) + D451 + pin 3 + pin 2 + DY + C461 +
vR451/R459.
An electric charge is then stored in C461. In the last half of
scanning the current path is:
C461 + DY+ pin 2+ pin 1 +VR451/R459 +C461
In this way, an increasing sawtooth waveform current
flows directly to the DY to perform electron beam
deflection. During the first half of the blanking period the
vertical ramp signal suddenly turns OFF. Since there is no
longer any current flowing into the DY, the magnetic field
collapses causing an induced current to flow as follows:
DY+ pin 2+ pin 1
@VR451/R459QC461 a DY
L
Once the magnetic field in DY has dissipated, the current
path becomes:
Vcc+ pin 6+ pin 7+ C452Q pin 3+
pin 2+ DY+ C461
+ VR451 /R459
.
and when the prescribed current value is reached, the
vertical drive ramp signal turns ON.
This completes one cycle.
6. HORIZONTAL OUTPUT
The horizontal oscillation signal is outputted from pin 37 of
IC101 and used to switch the drive transistor Q431. This
switching signal is current amplified by the drive
transformer T431 and drives the output transistor Q432.
When Q432 turns ON, an increasing current flows directly
to the DY through
C441 /C442 + L441 /R441 + DY + Q432- C + Q432- E
and the deflection occurs during the last half of the
scanning period. When Q432 turns OFF, the magnetic
LJ
field stored in the DY up to that point causes a resonant
current to flow into the capacitors C420 and C423 and
charges them.
The current stored in C420 and C423 then flows back to
the DY causing an opposite magnetic field to be stored in
the DY. This field then collapses increasing a current
which switches the dumper diode in Q432 ON. The
resonance state is completed, and an increasing current
then flows again directly to the DY through the dumper
diode.
By this means, the deflection in the first half of the
scanning period is performed. When Q432 turns ON at the
end of the first half of the scanning period, the deflection
during the last half is begun, thus completing one cycle.
In the PCC circuit consisting of Q461 and Q462, the
parabola signal supplied from the vertical circuit is added
at the horizontal output stage
and pincushion
compensation is performed by varying the DC bias.
Further, the ABL voltage is fedback to the base of Q462 to
compensate for width variations due to variations in the
beam current.
–5–
Service Adjustments
MAIN UNIT
B1 POWER SUPPLY ADJ.
HORIZONTAL WIDTH ADJ.
—
%
0718
a
w
IC790
0s57
*
MEMORY
%
0313
%
POWER
\
0311B
*
(SERVICE)
0312
POWER DRIVE
\
o
Pf
H-ORIVE
TRANS.
❑
T431
o
KOY
VR462
?n .-
1
/—
I II
0432
HORIZ.
OUT
I
0
IC451
T471
VERT,
F.B.T.
AMP,
J /)0
L~fl
VR451 VERT,
KSC
KB 0431
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VERT. CENTER \ [
0245
B
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-...-,
Ay+
W“*,, .
CRT UNIT
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a
Om
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0183
3
z
OIMB B $
I
ZS
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T181 T,’2
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W-1
3P~.3CWND
a
CIRCUIT WITH 5 WHZ
0181
DEMCOUIATK4
1
/
—
@
,,-.
/
0702
D
= VR120
m
07”: =
‘B
g Omz
‘- c:wR~ VR401
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I
w
B
0221
0101
AUOIO IN
(LEFT)
iR782
3LUE BIAS
VR762
REO BIAS
VR772
GREEN BIAS
VR761
BLUE ORIVE
VR761
REO ORIVE
–6–
Service Adjustments
SAFETY PRECAUTIONS :An isolation transformer should be connected in the power line between the receiver and the AC
line before any service is performed on the receiver.
X-RADIATION PRECAUTION The primary source of X-RADIATION in television receiver is the picture tube. The picture
tube is specially constructed to limit X-RADIATION emission. For continued X-RADIATION protection, the replacement tube must
be the same type as the original including suffix letter, Excessive high voltage may produce potentially hazardous X-RADIATION.
To avoid such hazards, the high voltage must be maintain within specified limit. Refer to this service manual for specific high
voltage limits. If high voltage exceeds specified limits, take necessary corrective action. Carefully follow the instructions for + B1 volt
power supply adjustment, and high voltage check to maintain the high voltage within the specified limits.
NOTE; Do not attempt this adjustment with weak signal.
(1) Tune the receiver to most clearest (or strongest) VHF
station in your area. Set the brightness and contrast
controls to maximum. Set the colour control to minimum.
(2) Set AGC (VR1 20) control to mid- range.
(3) Turn AGC control in direction which causes snow to appear,
then in the opposite direction until the snow iust disatmears.
(1) Connect DC meter to R761 (VR351 side) and the ground.
Set the +Bl adjustment control (VR351 ) to mid - range.
(2) Set the brightness and contrast to normal.
Tune the receiver to an active channel and synchronized
picture.
(3) Adjust +Bl adjustment control(VR351 ) for 140 f
0.5 volt
DC.
(1) Receive the monochrome circular pattern.
(2) Set the brightness and contrast to normal.
(3) Adjust VR401 for optimum horizontal center position.
Horizontal center
(1) Receive the monochrome circular pattern.
(2) Set the brightness and contrast to normal.
(3) Vertical centering can be adjusted by switching SW451.
Vertical center
i/
(1) Receive the monochrome circular pattern.
(2) Set the brightness and contrast to normal.
(3) Vertical size can be adjusted by using VR451.
m
.,.
.
\,
Vertical size
‘\.\ ./’
. .
(1) Receive the monochrome circular pattern.
(2) Set the brightness to normal and contrast to maximum.
(3) Adjust the focus control on the F.B,T for the best focus on
the screen center.
(1) Receiver the monochrome circular pattern.
(2) Set the brightness and the contrast to maximum.
(3) Set the drive volume (VR761 and VR781 ) at their
mechanical center.
(4) Set the bias volume (VR762, VR772 and VR782) to
minimum. (fully counter clockwise).
(5) Set the service switch (SW220) to the service side.
(6) Turn the screen volume on the FBT to obtain just visible
one coloured line.
(7) Adjust each bias volume (VR782- blue, VR772- green and
VR762- red) alternately until a dim white line produced.
(8) Set the service switch (SW220) to the normal side.
(9) Adjust the drive volume (VR781 - blue and VR761 - red)
alternately to produce normal black and white picture.
(1O)Check for proper grey scale tracking at all brightness
levels.
NOTE: If the grey scale adjustment is made after picturetube
replacement, check high voltage and sub - brightness
adjustment.
(1) Receive the monochrom circular pattern.
(2) Set the brightness and contrast to normal.
(3) If the picture is too wide or narrow, adjust the horizontal
width using VR462.
NOTE: The horiz, width adjustment affects the high voltage.
Therefore, recheck the high voltage.
(1) Connect a high voltage probe to anode lead of the picture
tube.
(2) Receive the monochrom circular pattern,
(3) Set the brightness and contrast to maximum.
(4) The high voltage must be between 28-30 f 1KV.
NOTE: If the picture tube is replaced, check the high voltage.
I
–7–
VIF Adjustment
Overall Waveform Adj.
Oscilloscope
k
—
c
o
.-
:
al
c
c
~
—
c
0
.=
.-
-0
c
6
—
R368(C364 side)
ICI 01- pin48
No band
DC 15V
IF AGC(3.5-4.5V)
BAND
Output Probe
Input Probe
Ground
SIF System
Sweep ATT.
Output Probe
Oscilloscope Sens.
R368(C364 side)
IC101 - pin48
No band (Q784-Base * Ground,
through 1k C? resistor)
TUNER-IF
Q122- Emitter
TP-A
TUNER-IF
Q1 22- Emitter
TP-A
100 S2Dumping Resistor*R124
any
18dB
any
18dB
side a
100mV/DIV
side a
100mV/DIV
Adjust the overall waveform level
to become lVP – p with IF AGC
VOLTAGE.
Adjust P (38.9MHz) to be
Adjustment
maximum amplitude by using
T121 .
D
A
J
Waveform
078?
J
o
D,
cm
w
0793
07C6
!’37
~,18 -
Input Probe
D
07M
Bcasd
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0%1
Omo
-#%Ft-
7
1311
cONVERTER
TR4NS.
lc7m
MEMORY
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L
x--
I
0
cm
0
L441
Detector Adj.
.----’
-a
100 S2Dumping
Resistor
a
U242
KDY
H- WIDTH
Y%
0702
““;G
Output Probe
w
T471
F,B.T.
-J ‘%
DOWN ~ UP
VERT. CENTER
MAIN UNIT
Nclum
(RlOHn
AUDn WT
AUW3 M
(Em
(lEFT)
(h Band Setting)
-“77
lKQ
–8–
SIF Adjustment
u
Item
Detector Adj.
DC 15V
R368(C364 side)
5 IF AGC(3.5- 4.5V) IC181 -pin 3
g Output Probe-1
IC181 -pin 1
: Input Probe
IC181 -pin 14
s
: Sweep ATT.
31 dB
~ Output Probe
side a
: Oscilloscope Sens.
100mV/DIV
3
Adjust AGC voltage to be
Adjustment
A=O.5VP -p.
By using T1 81, adjust P to be
equal center line.
+
(38.9 MHz) P A
Waveform
Item
FM Detector Adj.
DC 15V
R368(C364 side)
~ Output Probe-2
IC181 -pin 12
~ Input Probe
IC181 -pin 6
c
c
2
: Carrier Freq.
5.74 MHZ
- Mod. Freq
1KHz(sine wave)
z
= Scope Sens.
lVldiv
s
By using T1 82, adjust DC Voltage of
Adjustment
sine wave to be 4.OV.
Waveform
E
4.OV
DC=OV
D
cm
o
1441
n7911
MEMC+7Y
u
n~ n
w KBB
c
B
al n
07M
Dwd
OIM
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D D014J
cd57 /
Q7CQ
a
In OE!AY
07% mm
-T
a
0222
,.
0
:
q’”
~.1
H-CENTER
w
B
0221
Oml
ilX71 -g
TELETEXT UNIT
— I
I
~&w43EJ I ‘w
DOWN + UP
VERT, CENTER
AUDiU OUT
(Rk3HT1
–.
\
Detector Adj.
FM Detector Adj.
{
Input Probe
10KQ
+
Oscilloscope
I I
DC 3.5-4.5V
1
Output Probe-1
--E53!
\
Output Probe-2
* SIF Signal
Generator
MAIN UNIT
%%!!- ( ( ,,DEOI”
L
- VIDEO WT
AUDK3 CUT AUDk3 IN
(LEFT)
[LEFT]
–9–
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