Toshiba CN27E90 Installation guide

COLOR TELEVISION
CN27E90, CX32E70
CN32E90, CN35E15
CF35E50, CX35E60
CX35E70, CX35E81
CN35E90, CN35E95
TECHNICAL TRAINING MANUAL
N5SS (TG-1, C) CHASSIS
NTDCTV05
PRINTED IN JAPAN Aug. 1995 So

2
Contents
SECTION I
OUTLINE......................................................................6
1. OUTLINE OF N5SS CHASSIS (CN32E90, CN35E90) .................................................................... 7
2. PC BOARD CONFIGURATION........................................................................................................ 7
3. MAJOR SPECIFICATIONS (NEW FUNCTIONS IN ADDITION TO THOSE OF N5SS)........ 7
4. MODIFICATIONS ON CHASSIS..................................................................................................... 7
5. CONSTRUCTION OF CHASSIS...................................................................................................... 8
6. LOCATION OF CONTROLS............................................................................................................ 9
7. CN32D90 BLOCK DIAGRAM ......................................................................................................... 13
8. [US, CANADA] SPECIFICATION FOR MODEL's 1995 ............................................................ 14
SECTION II
TUNER, IF/MTS/S.PRO MODULE.........................16
1. CIRCUIT BLOCK ............................................................................................................................. 17
2. TUNER ................................................................................................................................................ 18
3. IF/MTS/S.PRO MODULE................................................................................................................. 19
4. PIP TUNER......................................................................................................................................... 23
SECTION III
CHANNEL SELECTION CIRCUIT........................24
1. OUTLINE OF CHANNEL SELECTION CIRCUIT SYSTEM.................................................... 25
2. OPERATION OF CHANNEL SELECTION CIRCUIT ................................................................ 25
3. MICROCOMPUTER......................................................................................................................... 26
4. MICROCOMPUTER TERMINAL FUNCTION ........................................................................... 27
5. EEPROM (QA02) ............................................................................................................................... 29
6. ON SCREEN FUNCTION................................................................................................................. 29
7. SYSTEM BLOCK DIAGRAM .........................................................................................................30
8. LOCAL KEY DETECTION METHOD .......................................................................................... 31
9. REMOTE CONTROL CODE ASSIGNMENT............................................................................... 32
10. ENTERING TO SERVICE MODE................................................................................................ 35
11. TEST SIGNAL SELECTION ......................................................................................................... 35
12. SERVICE ADJUSTMENT .............................................................................................................. 35
13. FAILURE DIAGNOSIS PROCEDURE......................................................................................... 36
14. TROUBLE SHOOTING CHART .................................................................................................. 38
SECTION IV
AUDIO OUTPUT CIRCUIT .....................................41
1. OUTLINE............................................................................................................................................ 42
2. AUDIO OUT IC.................................................................................................................................. 43

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SECTION V
A/V SWITCHING CIRCUIT ....................................44
1. OUTLINE............................................................................................................................................ 45
2. IN / OUT TERMINALS..................................................................................................................... 45
3. CIRCUIT OPERATION.................................................................................................................... 45
SECTION VI
VIDEO PROCESSING CIRCUIT............................47
1. OUTLINE............................................................................................................................................ 48
2. SIGNAL FLOW.................................................................................................................................. 48
3. CIRCUIT OPERATION.................................................................................................................... 48
SECTION VII
V/C/D/IC......................................................................52
1. OUTLINE............................................................................................................................................ 53
2. LARGE SCALE EMPLOYMENT OF BUS CONTROL OF PARAMETER FOR PICTURE
CONTROLS...................................................................................................................................... 53
3. EMPLOYMENT OF CONTAINING EACH VIDEO BAND FILTER INSIDE.......................... 53
4. EMPLOYMENT OF CONTAINING EACH FILTER (FOR S/H) INSIDE................................. 53
5. LOW COST OF IC ............................................................................................................................ 53
SECTION VIII
PIP MODULE.............................................................55
SECTION IX
SYNC SEPARATION, H-AFC,
H-OSCILLATOR CIRCUITS ..............................58
1. SYNC SEPARATION CIRCUIT ......................................................................................................59
2. H AFC (Automatic Frequency Control) CIRCUIT......................................................................... 60
3. H OSCILLATOR CIRCUIT ............................................................................................................. 61
SECTION X
VERTICAL OUTPUT CIRCUIT .............................63
1. OUTLINE............................................................................................................................................ 64
2. V OUTPUT CIRCUIT ....................................................................................................................... 65

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SECTION XI
HORIZONTAL DEFLECTION CIRCUIT..............69
1. OUTLINE............................................................................................................................................ 70
2. HORIZONTAL DRIVE CIRCUIT................................................................................................... 70
3. BASIC OPERATION OF HORIZONTAL DRIVE ........................................................................ 71
4. HORIZONTAL OUTPUT CIRCUIT............................................................................................... 74
5. HIGH VOLTAGE GENERATION CIRCUIT................................................................................. 79
6. X-RAY PROTECTION CIRCUIT ................................................................................................... 82
7. OVER CURRENT PROTECTION CIRCUIT................................................................................ 83
8. KINK CORRECTION CIRCUIT..................................................................................................... 84
SECTION XII
DEFLECTION DISTORTION CORRECTION
CIRCUIT (Side DPC Circuit)..............................85
1. DEFLECTION DISTORTION CORRECTION IC (TA8859P) .................................................... 86
2. SIDE DPC............................................................................................................................................ 87
3. DIODE MODULATOR CIRCUIT ................................................................................................... 88
4. ACTUAL CIRCUIT........................................................................................................................... 89
SECTION XIII
CLOSED CAPTION/EDS CIRCUIT .......................92
1. OUTLINE............................................................................................................................................ 93
2. DATA TRANSMISSION FORMAT ................................................................................................ 93
3. DISPLAY FORMAT........................................................................................................................... 94
4. CIRCUIT OPERATION.................................................................................................................... 95
SECTION XIV
POWER CIRCUIT.....................................................98
1. OUTLINE............................................................................................................................................ 99
2. RECTIFYING CIRCUIT AND STANDBY POWER SUPPLY................................................... 100
3. MAIN SUPPLY CIRCUIT............................................................................................................... 100
4. OUTLINE OF CURRENT RESONANT TYPE SUPPLY ........................................................... 101
5. FUNDAMENTAL THEORY........................................................................................................... 101
6. ACTUAL CIRCUIT......................................................................................................................... 102
7. OTHER POWER CIRCUIT ........................................................................................................... 105
8. PROTECTOR MODULE (Z801).................................................................................................... 106

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SECTION XV
DSP CIRCUIT ..........................................................109
1. ORIGINS OF DOLBY SURROUND ............................................................................................. 110
2. THE DOLBY MP MATRIX............................................................................................................ 110
3. THE DOLBY SURROUND DECODER.........................................................................................111
4. DSP CIRCUIT ...................................................................................................................................111
5. DSP (Digital Surround Processor) IC............................................................................................. 114
6. SURROUND CIRCUIT ................................................................................................................... 116
7. INPUT BALANCE CIRCUIT......................................................................................................... 116
8. MATRIX CIRCUIT ......................................................................................................................... 117
9. FILTER CIRCUIT (ANTI-ALIAS FILTER)................................................................................. 117
10. DSP CIRCUIT (DELAY) ............................................................................................................... 118
11. 7 kHz LOW PASS FILTER ........................................................................................................... 119
12. DOLBY NR CIRCUIT................................................................................................................... 120
13. DSP FRONT ADDITION CIRCUIT............................................................................................ 121
14. BUS CONVERTER ........................................................................................................................ 122
15. NEUTRAL BIAS ............................................................................................................................ 122
16. AUDIO OUTPUT AMPLIFIER (For Rear SP) .......................................................................... 123
17. TROUBLESHOOTING CHART ................................................................................................. 124
SECTION XVI
FAILURE DIAGNOSIS PROCEDURES...............125
1. H STARTING CIRCUIT FAILURE DIAGNOSIS PROCEDURES........................................... 126
2. DEFLECTION CIRCUIT FAILURE DIAGNOSIS PROCEDURES......................................... 127
3. LEFT-RIGHT PIN-CUSHION DISTORTION CORRECTION CIRCUIT.............................. 128
4. X-RAY PROTECTION CIRCUIT FAILURE DIAGNOSIS PROCEDURES........................... 129
5. PROTECTION CIRCUIT DIAGNOSIS PROCEDURE ............................................................. 130
6. VIDEO CIRCUIT DIAGNOSIS PROCEDURES......................................................................... 131

6
SECTION I
OUTLINE

7
1. OUTLINE OF N5SS CHASSIS
(CN32E90, CN35E90)
The N5SS chassis is a complete bus control type
chassis where the deflection circuit is controlled by a newly
developed I2C-bus line control system.
2. PC BOARD CONFIGURATION
(1) Signal unit
(2) Power/def unit
(3) A/V, CRT-D, SP-TERM
(4) CCD, comb (CN32E90)
Digital comb (CN35E90)
(5) D.S.P unit
(6) C.C, EDS/R.G.B SW
3. MAJOR SPECIFICATIONS (NEW
FUNCTIONS IN ADDITION TO THOSE
OF N5SS)
(1) EOS (Extended-Data-Service)
(2) Center-Ch-Audio-Input provided
4. MODIFICATIONS ON CHASSIS
(1) Serviceabilityimprovedwithdirect,frontaccesssystem
employed.
(2) One touch cabinet securing (CN32E90) to the chassis.
(3) Improved serviceability with the bus control system
employed for the defection circuits.
(4) Improved serviceability with the white balance bus
control system employed.
(5) Digitalcomb/CCD miniaturized into a socketable size.

8
Fig. 1-1
5. CONSTRUCTION OF CHASSIS
REAR AMP circuit
CONVERTER trans
POWER/DEF circuit
H.OUT
H.OUT trans
DPC circuit
V. OUT
RF SW
A/V circuit
CRT circuit
PIP circuit
CCD circuit
DPC circuit
EDS, RGB SW
circuit
AUDIO OUT
IF/MTS/A-PRO
module
SIGNAL circuit

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6. LOCATION OF CONTROLS
6-1. TV Set
For specific use of each control, consult the corresponding page numbers in brackets.
Fig. 1-2
POWER
Front View
Press to open
the door
Behind the door
VIDEO/AUDIO IN
jacks <VIDEO 3>
DEMO button
MENU button
CHANNEL buttons
VOLUME
-/+buttons
buttons
ANT/VIDEO button
ADV button
POWER indicato
r
POWER button
Remote sensor

10
Fig. 1-3
Rear view
ANTenna terminals
EXTernal SPEAKER
t
erminals
MAIN SPEAKER
switch
REAR SPEAKER
terminals
S-VIDEO IN jack <VIDEO 1>
VARiable AUDIO OUT
jacks
VIDEO AUDIO OUT
jacks
PIP AUDIO OUT
jacks
VIDEO/AUDIO IN jacks
<VIDEO 2>
VIDEO/AUDIO IN jacks
<VIDEO 1>