Sanyo CE21FN1E, CE28FN1-E, CE25FN1-E Schematic

Service Manual

Colour Television

Models:

CE28FN1-E CE25FN1-E CE21FN1-E

CRT 28” A59EAK071X11 CRT 25” A66EAK071X11 CRT 21” A51EAL155X10 CRT 21” A51EAL155X11

CHASSIS No 2103 EB5-A

Index

1. Safety instructions..................................................................................................................................................................................................1

2. WARNING.............................................................................................................................................................................................................1

3. Precaution against X-Rays.....................................................................................................................................................................................1

4. Technical characteristics........................................................................................................................................................................................2

5. Safety.....................................................................................................................................................................................................................2

6. EMC (Electromagnetic Compatibility).....................................................................................................................................................................2

7. Factory special mode..............................................................................................................................................................................................3

8. “HOTEL” and “RENTAL” modes............................................................................................................................................................................3

9. Automatic channel search reactivating...................................................................................................................................................................3

10. Block diagram.......................................................................................................................................................................................................4

11. Power supply........................................................................................................................................................................................................5

12. Microprocessor and Teletext ................................................................................................................................................................................5

13. Video processor/Comb filter.................................................................................................................................................................................5

13.1 Video Intermediate Frequency Section ..........................................................................................................................................................5

13.2 Horizontal and vertical synchronisation..........................................................................................................................................................5

13.3 Geometry.......................................................................................................................................................................................................6

13.4 Filters and video switches..............................................................................................................................................................................6

13.5 Colour decoder ..............................................................................................................................................................................................6

13.6 RGB Processing............................................................................................................................................................................................6

13.7 RGB Control..................................................................................................................................................................................................7

13.8 Supply and bandgap decoupling....................................................................................................................................................................7

14. Audio processor/A3D Surround/Output amplifiers/Sound IF................................................................................................................................7

15. Service menu........................................................................................................................................................................................................8

16. Adjustment and repair procedures .....................................................................................................................................................................10

16.1 Notes about the adjustment:........................................................................................................................................................................10

16.2 Switch-on sequence. ...................................................................................................................................................................................11

16.3 Protect modes and failure indication............................................................................................................................................................11

16.4 Protect mode inhibition ................................................................................................................................................................................11

16.5 Power supply repair procedure....................................................................................................................................................................11

16.6 Non-volatile memory (NVM) replacement, IC125.........................................................................................................................................11

17. Failure location flow-charts.................................................................................................................................................................................12

18. Complete PCB codes for after sales service......................................................................................................................................................15

19. CHASSIS ELECTRICAL PARTS LIST CE21FN1-E / CE25FN1-E / CE28FN1-E ...........................................................................................16

20. CE21FN1-E CABINET PARTS LIST ................................................................................................................................................................17

21. CE25FN1-E CABINET PARTS LIST ................................................................................................................................................................18

22. CE28FN1-E CABINET PARTS LIST ................................................................................................................................................................19

23. Parts List............................................................................................................................................................................................................20

Give complete “SERVICE PART No” for parts order or servicing, it is shown on the rating sheet on the cabinet back of the TV set.

16-11-1998

Note This TV receiver will not work properly in foreign countries where the television transmission system and power source differ from the design specifications. Refer to the specifications for the design specifications.

Ref. Nº

MS CE25FN1-E

Service Manual MS CE25FN1-E

1. Safety instructions

Read this page before doing any operation of adjustment, maintenance or repair the TV set described. Only skilled personnel of Sanyo Technical Service should do the adjustment, maintenance or repair of TV set.

2. WARNING

For the correct and safe use of the TV set, it is essential that the service personnel follow the process of safety generally accepted and the safety precautions specified in this manual.

An isolation transformer should be connected in the power line between the receiver and the AC line when a service is performed on the primary side of the converter transformer of the set.

3. Precaution against X-Rays

The primary source of X-RADIATION in the television receiver is the picture tube. The picture tube is specially constructed to limit X-RADIATION emissions. 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 maintained within specified limit. If high voltage exceeds specified limits, take necessary corrective action. Follow the instructions carefully for +B1 volt power supply adjustment, and high voltage adjustment to maintain the high voltage within the specified limits.

COMPLIANCE TO STANDARDS

All of those marked with X or must be

replaced with original parts

WARNING! This TV set contains components which

are particularly sensitive to static electricity (ESD). It is recommended that all due precaution be taken

handling integrated circuits and semiconductors.

4. Technical characteristics

Cathode-ray tubes 21” (54 cm) Model CE21FN1-E

25” (65 cm) Model CE25FN1-E 28” (70 cm) Model CE28FN1-E In-Line gun type. Black Matrix.

Tuning system Program selection Receiving channels

(Cable and Aerial) TV system

Colour system Audio power Speakers Aerial Headphones AV connectors

Power source Power consumption CE25FN1-E and CE28FN1-E

Power consumption CE21FN1-E

STEREO Systems Sound effects Comb Filter Models CE25FN1-E and CE28FN1-E Clock function Alarm function Timer function Teletext

Hotel mode

Voltage synthesis, 100 programs in non volatile memory, AFT, fine tuning (first 10 programs), automatic, semiautomatic and manual channel search. Sequential selection from the controls on the set. Direct selection of any program from the remote-control device. Band I channels E2 ... E4; S1 ... S10; Band III channels E5 ... E12; S11 ... S41; Band IV-V channels E21 ... E69. B/G and D/K systems PAL, NTSC 4.43 2 x 8 W rms, 10% distortion

2 x 8 Ω, full range External aerial-socket 75 Ω IEC. Jack stereo 3,5 mm (with independent control). 1 SCART connector 21-pin, standard CENELEC AV and RGB. 1 SCART connector 21-pin, standard CENELEC AV and S-video. 1 RCA type Video input (front). 2 RCA type Audio R/L input (front). 220 Vac ... 240 Vac, 50 Hz. 108 W (maximum). 72 W (IEC 107-1)

2.5 W (stand-by). 87 W (maximum). 65 W (IEC 107-1)

2.3 W (stand-by). Nicam and A2. Active 3D Surround. Pseudo Stereo. Bass boost. Auto volume

Auto capture from teletext. Programmable over 24 hours. Switch on and off are programmable over 24 hours. Level 1.5 Flof, Top and List. 10 teletext pages memory. East european TXT included. Can be programmed in Hotel and Hotel Rental mode.

Service Manual MS CE25FN1-E

5. Safety

It fulfils the safety requirements established in the regulation:

• EN 60065:93

6. EMC (Electromagnetic Compatibility)

It fulfils the EMC requirements established in the regulation:

• EN 55013:1990/A12:1994

• EN 55020:1994

• EN 60555-2:1987

Service Manual MS CE25FN1-E

7. Factory special mode

The factory mode is a special TV working mode intended to help in the manufacturing process and it is identified on the screen with the message “FAC”. This mode is never suited for customer use. The main differences respect to normal mode are:

1- The standby mode is always disabled. 2- The Blue-back (no sync. signal present) is disabled.

3- The customer adjustments ( volume, contrast …) work faster. In case of finding the TV set in Factory mode, it must be taken out of this state. To do so, enter the clock setting menu on the customer OSD and then exit.

8. “HOTEL” and “RENTAL” modes

The TV set has a special mode of operation that is adapted for use in hotels, hospitals… Its main purpose is to avoid the manipulation of the basic TV settings. This mode is stored in NVM, so it is maintained even though the TV set is disconnected from the mains. Its main features are:

1. The maximum volume level is limited to the volume chosen when the mode is entered.

2. Channel searching and fine tuning are disabled.

3. The TV set always switches on with the normalisation settings and users can not memorise any of their

personal preferences.

4. Language selection and child lock are disabled.

5. It is possible to force the TV set to always switch-on in a selected program between the 1st and 8th or AV1. To activate this mode, hold down the “VOL -” front key and simultaneously, press the “RECALL” remote control

key. A message like “ HOTEL: 00 “ will appear waiting for two digits entry. The most significant digit indicates the selected mode:

‘0’: normal mode ‘1’: HOTEL mode ‘2’: RENTAL mode The second digit indicates the programme in which the set will switch on:

‘0’: the same as it was selected when the TV set was switched off (normal mode)

‘1’ to ‘8’: always this programme selection (1 to 8).

‘9’: always AV1 mode The ‘RENTAL’ mode has the same features as the ‘HOTEL’ mode and additionally the front keys are inhibited

so it is only possible to change the program with the remote control. In order to exit from this mode, the colour saturation level must be set to zero.

9. Automatic channel search reactivating

In order to reset the initial automatic channel search function, start a channel search in AUTO mode from the user tuning menu and switch-off the TV set before any station is found. The next time the TV set is switched on, it will start an automatic channel-search.

10. Block diagram

Service Manual MS CE25FN1-E

11. Power supply

First, let’s define some TV states or working modes to clarify later explanations:

State Description

SMPS_B_LOW The power supply is in low consumption (low voltage). The deflection is stopped.

SMPS_B_HIGH The power supply works at nominal voltage. The deflection can be on or off.

STANDBY The micro stops “B_HIGH” port oscillation and the power supply is on “SMPS_B_LOW”.

ON The power supply is on “SMPS_B_HIGH” and deflections are on.

ERROR_N Protect situation. The power supply is on SMPS_B_LOW and the micro shows the error by

the led indicator. The TV is not allowed to switch-on (except ERROR_5).

The power supply works in switched mode with “flyback” self oscillating topology and with control in current mode. The outputs of the source are shown in the block diagram. Also there are:

• B8: feeds the power supply controller. The initial source in switch-on situation is extracted through

R803+R816.

• B9: feeds the optocoupler primary part. The power supply sends two signals to the micro processor:

• -PD&FAIL: Switch-off immediately (mains off).

• 16/9&BSYNC: Mains pulses synchronism and 16/9 control. The micro analyses this line in order to switch

correctly from SMPS_B_LOW to SMPS_B_HIGH. In STAND-BY mode all the voltage outputs are reduced except the microprocessor supply (it remains at 5

volts). The triac TR830 disconnects the PTC800 supply.

12. Microprocessor and Teletext

The microprocessor (IC100) main tasks are the following:

• video processor control

• audio processor control

• NVM access

• IR decoding

• Teletext processing and display

• OSD generation

• tuning and AFT

• failure checking

• …

13. Video processor/Comb filter

The video processor (IC400) has the following functional blocks: video Intermediate frequency, mono sound (not used), vertical and horizontal synchronism, geometry processor, video switching and filtering, colour decoder and RGB processing. All the adjustments are performed by the microprocessor via the I2C bus.

13.1 Video Intermediate Frequency Section

• I.F Amplifier: The input signal comes from the tuner (TU250) through the S.A.W. filter SF200 (band pass

filter of the video information and the picture carrier.

• PLL Demodulator and VCO: The VCO does not need any adjust neither external coil. The frequency

adjustment is performed through the I2C bus. The components associated with the PLL are connected to

the pin 5 (PLLLF).

• Video buffer: The demodulated video signal is present at pin 6 (IFVO) with a typical level of 2Vpp.

• AGC: It controls the IF amplifier gain in order to maintain its amplitude constant. The capacitor connected to

the pin 53 (DECAGC) determines the AGC time constant.

• Tuner AGC: It reduces the gain when a high level aerial signal is received. The level at which this reduction

is performed is I2C bus adjusted (AGC in the service menu).

• AFC: The AFC information is accessible via I2C bus.

• Video identification: The video identification information is accessible via I2C bus.

13.2 Horizontal and vertical synchronisation

• Horizontal sync separator

• Horizontal oscillator: it is internal and only needs the crystal oscillator X400 as a reference frequency.

• PHI-1 detector: It is a PLL that synchronises the horizontal oscillator with the video signal. The components associated with the PHI-1 are connected to the pin 43 (PH1LF). The PHI-1 time constant and the noise

Service Manual MS CE25FN1-E

detector are controlled via I2C bus.

• PHI-2 detector and Sandcastle generator: The PHI-2 detector performs a stable picture. It synchronises the

horizontal oscillator with the horizontal flyback signal (pin 41, FBISO) to generate the horizontal output (pin

40, HOUT). . The components associated with the PHI-2 are connected to the pin 42 (PH2LF). The picture

phase is adjusted via I2C (HOR SHIFT in the service menu). The flyback input pin 41 (FBISO) is combined

with the sandcastle output and provides a three level sandcastle signal. The levels are: 2V à vertical

retrace; 3Và horizontal retrace; 5.3V àBurstkey.

• Horizontal output (pin 40, HOUT): It is a open collector type and the duty cycle in normal condition is 45%

high and 55% low. A built in slow start/stop circuit ensures a smooth start/stop behaviour of the line

deflection. Also during switching off via stand by the RGB drive is set to maximum to discharge the EHT

CRT capacitance.

• Coincidence detector

• Vertical sync separator

• Vertical divider

13.3 Geometry

• Vertical sawtooth generator: it delivers the reference signals for vertical and horizontal geometry processor.

An accurate reference current is used to charge the external capacitor during vertical scan. The resistor

R426 in pin 52 (IREF) determines this reference current. It is a Metal Film resistor with 1% tolerance in

order to provide a temperature stabilisation and lower dispersion. The ramp capacitor (C425) is connected

to pin 51 (VCS). It is a polycarbon one in order to provide temperature stabilisation.

• Vertical geometry processor: it performs the sawtooth signal and it has a differential current output in pins

47 (VDRA) and 46 (VDRB) for a DC coupled vertical output stage (drive). Control functions accessible via

I2C are VERT SLOPE, VERT AMPL, S-CORREC, VERT SHIFT (see service menu).

• Horizontal geometry processor (E/W drive): it has a single-ended current output for E-W drive (pin 45

EWD). This current is amplified and applied to the diode modulator of the horizontal deflection. The

adjustments are accessible via I2C (EW AMPLIT, PARABOLA, CORNER PAR, TRAPEZIUM in the service

menu).

• EHT tracking (pin 50, EHTO): this tracking makes the picture size independent of EHT variations due to the

beam current.

13.4 Filters and video switches

• Video signal selection: the input selector has CVBS_INT(pin 13), CVBS_EXT (pin 17), CVBS/Y (pin11) and

CHROMA (pin 10) as inputs which can be selected via I2C bus. The selected video signal is present at pin

38 (CVBSO).

• Filter calibration: it is an auto-tuning loop which calibrates every field retrace. The filters are the

chrominance bandpass and the chrominance trap.

• Chrominance signal processing: this circuit keeps constant the colour saturation level.

• Luminance signal processing: the selected video signal is supplied to the chrominance trap. The output

signal is supplied to the peaking and coring stages. Both are controlled via I2C bus. The output (pin 28

LUMOUT) is fed through a band pass filter (L409, R439 and C440) as internal luminance signal (pin 27

LUMIN).

13.5 Colour decoder

• PLL/VCXO: The PLL operates during the burstkey period. In the lock condition the VCXO reference signal

(X400 in pin 35) and the burstkey become synchronous. An optimum transient response can be chosen with

the loop filter connected to pin 36 (DET). The reference output (4,43MHz in pin 33) can be used for comb

filter applications.

• PAL/NTSC Demodulation: The reference signals from the VCXO are supplied to the HUE phase rotator; its

outputs are supplied to the (R-Y) and (B-Y) demodulators. The (B-Y)/(R-Y) baseband signals are filtered and

supplied via the PAL/SECAM switch to the internal baseband delay line. The signals from the delay line are

RYO (pin 30) and BYO (pin 29).

• SECAM Demodulation: It is realised with a PLL type demodulator. The SECAM reference voltage is

generated at pin 16 (SECPLL). The demodulated signal is distributed to the (R-Y) and (B-Y) amplifiers and

via de PAL/SECAM switch to the baseband delay line.

• Automatic system manager: it can identify PAL/SECAM/NTSC colour standards. The different possibilities

are controlled by the I2C bus.

13.6 RGB Processing

• (R-Y)/(B-Y) processing/matrixing: The amplitude of this signals (pins 32 (RYI) and 31 (BYI)) is controlled via

the I2C bus (colour saturation) and also this signals are supplied to dynamic skin control. After the R-Y and

Service Manual MS CE25FN1-E

B-Y matrixing, the output signals are added with the luminance signal in order to generate the internal RGB

signals.

• RGB selector: it is controlled by the FB signal in signal 26 (RGBIN). The external RGB signals are present

in pins 23 (RI), 24 (GI) and 25 (BI). The RGB selector output is fed to then RGB control.

13.7 RGB Control

• Contrast and brightness control: There are I2C bus controlled. These adjustments can be reduced by the

beam current limiter stage. Furthermore, contrast is affected by the Peak Beam Limiter (Q670 and Q671

circuitry). This circuit’s output is the PBL signal to microprocessor’s pin 11 and must be 5V with a black

pattern on the screen.

• Beam current limiter/vertical guard: The BCLIN (pin 22) input circuit functions as an average beam current

limiter as well as a peak white limiter. The vertical deflection works correctly when there is a pulse level

above 3.7V during the vertical retrace. The vertical guard function can be I2C controlled. The contrast and

brightness reduction begins when BCLIN level is below 3.0V and 2.0V respectively.

• Continuous cathode calibration (AKB): it is divided into two loops: a black level stabilisation and a cathode

drive stabilisation. Each gun of the CRT is stabilised sequentially and independently and a feedback current

flows to the black current input (pin 18 BLKIN) supplied by the RGB amplifier (IC500). In order to change the

cathode levels at the picture tube three I2C bits are available.

• White point adjust and blue stretcher.

13.8 Supply and bandgap decoupling

The IC400 has two supply pins 12 and 37. Both pins must be supplied simultaneously. The nominal supply voltage is 8V. The pins 14 and 44 must be connected to ground. The bandgap circuit provides a very stable and temperature independent reference voltage that ensures optimal performance of the video processor. Short decoupling (pin 9 DECBG) to pin 14 of the external capacitor is important for stable horizontal drive.

The comb-filter (IC1050) is only performed with a PAL signal. To enhance the image quality its main features are: cross colour reduction (only at vertical frequencies), cross luminance reduction and improved video bandwidth. The input signal is composite video. It comes from the IC400 (pin 38 CVBSO) to the pin 17 (YEXT/CVBS). It is processed internally and the resultant signals are Luminance (pin 14 Y0) and chrominance (pin 12 C0). These signals return to the colour decoder in the video processor. The comb-filter is switched on through the I2C bus by writing a bit in the video processor. This one outputs a 4,43MHz signal on the REF0 port superposed to a high level one. With SECAM, NTSC or S-VHS signals the comb-filter is disabled. It bypasses the luminance (pin 17 YEXT/CVBS- to pin 14 -YO-) and chrominance (pin 10 -CEXT- to pin 12 -CO-) signals. The video processor outputs a low level on pin 33. In the models without the comb-filter, the jumpers JO1050 and JO1051 bypass the signals.

14. Audio processor/A3D Surround/Output amplifiers/Sound IF

The audio processor (IC1300) is controlled via I2C bus. It has 3 main sections: analog, digital and DSP (digital signal processing).

• The analog part takes: audio input and output switching, A/D and D/A conversion of input/output sound

signals.

• The digital part: demodulates FM (multistandard) and decodes the two carrier signals, controls the sound IF

AGC, demodulates DQPSK (multistandard) and decodes NICAM.

• The DSP section takes: sound controls, sound effects for loudspeakers, mute for loudspeakers and

headphones, beeper (alarm function) and digital audio switching matrix. The IC1380 produces the Active 3D Surround (A3DS) effect. The models without A3DS effect use the jumpers

JO1381 and JO1382 to bypass the audio signals to the audio amplifier for loudspeakers. IC300 is the stereo audio amplifier for loudspeakers, it has a variable gain through the resistive dividers

R303/R304 and R305/R306 (for channels L and R respectively). The power driven is approximately 8W rms. at 10% of distortion (each channel). The input pins (1 and 5) are connected to the audio processor (IC1300) or to the Active 3D Surround in models that have this feature. Pins 10 and 8 are the loudspeakers power outputs (channels L and R respectively). The microprocessor can mute the audio by setting high the MUTE signal. This pin is used only at TV set switch-on and off and in case of bad aerial reception. In all other situations the mute function is performed by the IC1300.

A fixed gain stereo amplifier is used for headphones (IC350). The input pins (7 and 6 for channels L and R) come from the audio processor headphones outputs. The headphones connector outputs are the pins 1 and 3.

Service Manual MS CE25FN1-E

The microprocessor detects the headphones presence via the HP_SW signal. The MUTE signal also affects the headphones audio. The FM or NICAM-modulated sound IF signal, which inputs the audio processor, is produced by the sound IF circuit, IC1350. This IC takes the signal from the tuner and converts it to the intercarrier frequency. The internal VCO frequency is adjusted by means of L1351.

15. Service menu

The service menu is accessed by holding down the front key “VOL-“ and simultaneously pressing the teletext green key from the remote control. The service menu is a two level structure as shown in the diagram below. The active keys (local or remote) in service mode are: VOL-, VOL+, P-, P+, MENU and the digits. The navigation through this menu works the same than in the user menu. * The P+ and P- keys allow to navigate through the options in the active menu. * The VOL+ key opens the second level menu if available. If there is a highlighted adjustment, the VOL- and VOL+ keys allow to change it. * The MENU key goes back one level menu. If the active menu is the main one, it exits the service mode. * The digit keys allow direct entry for adjustments. * The SERVICE mode is exited by pressing any other key.

SERVICE

GEOMET

HOR SHIFT

EW AMPLIT

PARABOLA

CORNER PAR

TRAPEZIUM

VERT SLOPE

VERT AMPL

S-CORREC

VERT SHIFT

VIF

PLL

PLL L'

AGC

WHITE

GREEN

BLUE

BRI

ADJ

AKB

K-DRV

Y/C PAL

Y/C SECAM

Y/C NTSC

Y/C AV

PBL SPEED

CONTR OSD

CONTR TXT

CENTR TXT

SEMI MUTE

INI NVM

CONFIG

TXEAST

FFI

SCS

CMB

DSA

OSO

OEM

16:9

STANDARD

PAL BG

PAL DK

PAL I

SECAM BG

SECAM DK

SECAM L

NTSC BG

NTSC M

V-STAT S-STAT I2C BUS

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