Toshiba MM20E45 Installation guide

COLOUR TELEVISION
MM20E45
TECHNICAL TRAINING MANUAL
FILE NO.016-9502
N5MM1 Chassis

CONTENTS
SECTION I
OUTLINE
SECTION II
CHANNEL SELECTION CIRCUIT
SECTION III
RGB SIGNAL PROCESSING CIRCUIT
SECTION IV
CRT DRIVE CIRCUIT
SECTION V
MODE DISCRIMINATING CIRCUIT AND SYNC SIGNAL PROCESSING CIRCUIT
SECTION VI
SYNC SEPARATION CIRCUIT OF TV MODE
SECTION VII
HORIZONTAL AND VERTICAL OSCILLATION CIRCUIT
SECTION VIII
VERTICAL DEFLECTION CIRCUIT
SECTION IX
HORIZONTAL DEFLECTION CIRCUIT
SECTION X
PROTECTION CIRCUIT
SECTION XI
OSD STABILIZATION CIRCUIT
SECTION XII
PICTURE TUBE
SECTION XIII
POWER SUPPLY CIRCUIT
SECTION XIV
FAILURE DIAGNOSIS PROCEDURES

1-1
SECTION I OUTLINE
1. OUTLINE OF N5MM1 CHASSIS
(MM20E45)
Thismodelisa20”colorTVwith181channeltunerandbuilt
in VGA and Mac II capability. The hybrid design of this
model allows it to serve several purposes. Television
reception, a monitor running Multimedia, PC applications,
or for playback of video games. The 20” FST picture tube
features a stripe pitch 0.58mm, providing a favourable
comparisonstoconventionaldesignswhichgenerallymeasure
0.75 to 0.9mm.
2. PC BOARD CONFIGURATION
(1) Power/V.C.D. PB5226
PB5226-1 Power
PB5226-2 V.C.D.
(2) Deflection PB5227
(3) Signal/Video PB5228
PB5228-1 Signal
PB5228-2 Video
PB5228-3 D-SUB

1-2
3. CONSTRUCTION OF CHASSIS
Power unit
Converter trans
Converter trans
Stand by trans
Sound out radiator
V out radiator
Choke coils
Choke trnas
H out radiator
Signal unit
Jack board
S-VIDEO
Tuner
Video unit
D-sub unit
D-sub connector
Front keys
Power LED
Remote control
receiver
Flyback trans
Def unit
V/C/D unit
Rectifier
Power radiator

1-3
4. LOCATION OF CONTROLS
4-1 TV Set
RGB/
TV/VIDEO
button
MENU button
ADV button
VOLUME
CHANNEL
POWER indicator
REMOTE senser
POWER button

1-4
4-2 Remote Control
ThisRemoteControlallowsyoutocontrolthefunctionsofyourTVsetfrom16feet(5m)away.The“*”markedfunctionbuttons
do not have duplicate locations on your TV set. They can be controlled only by the Remote Control.
Aim at the TV set
TIMER button*
Channel Number
buttons*
CH RTN (Channel Return)
button*
MTS button*
POWER button
MUTE button
SET UP button*
-/+ buttons
OPTION button*
RESET button*
PIC (Picture)* button
T
V/VIDEO button
RECALL button*
AUD (Audio) button*
CHANNEL button
s
VOLUME buttons

1-5
4-3 Monitor Panel
This TV set is equipped with RGB INPUT connector, RGB AUDIO INPUT jacks, S-VIDEO INPUT jack, VIDEO/AUDIO
INPUT jacks and VARIABLE AUDIO OUTPUT jacks of connecting your desired personal computer and video/audio
equipment.
TV Rear
34251
RGB INPUT Connector – provide for direct connection of a personal computer.
RGB AUDIO INPUT Jacks – provide for direct connection of a personal computer with audio output terminals.
S-VIDEO INPUT Jack – provide for direct S-video connection from an S VHS VCR or a video disc player.
VIDEO/AUDIOINPUTJacks–providefordirectconnectionofvideodevices(VCR,videodiscplayer,camcorder,etc.)
with video/audio outputs.
VARIABLE AUDIO OUTPUT Jacks – feed volume-controlled stereo audio out from whatever displayed on the screen,
allows connection of audio amplifier and lets you adjust sound level with TV’s remote.

1-6
5. MM20E45 BLOCK DIAGRAM
Tuner/IF module
20VMMTV BLOCK DIAGRAM
Signal switching
TC4053BP
Audio control
CXA1774S
Micro-computer
Memory
Band pass
Audio output
TA8200AH
C. CAP slicer
Synchronizing signal process M52346SP
Signal switching
TA7730
R-output
Vertical output
LA7837
Horizontal drive Horizontal
output
Mode distinction TA75339AP TC74HC86AP TC4514P TA75902 Horizontal/vertical
oscillation LA7860
S-shape capacitor switching
Linear coil switching
Resonance
capacitor
switching
Drive
switching
Synchronizing
signal switching
TC40538P
F/V conversion
IR9331 Horizontal amplitude
control chopper Horizontal drive Horizontal
output
Power unit
To be added for MM
Model change
( ) For MM
RGB
RF VIDEO
L
R
D.L
Signal
switching
AN5862K
Resonance
capacitor
switching
L
R
V/C/D
TA8801
OSD
R G B
R G B
R-Y G-Y B-Y -Y
EH
G-output B-output
VAR. OUT
FBT
VIDEO
(VERT)
(+15V)
(HEATER)
DAC
DPC
TA8859AP
HEATER
+15V AUDIO VERT.
+100V
TV & MM
H.Sync V.Sync Syncon G
High voltage
control chopper
Drive
switching
L
R
H V

1-7
6. SPECIFICATIONS
SPECIFICATIONS MODEL No. MM20E45
GENERAL
1 Picture Tube D/T Invar
2 Channel Capacity 181ch
3 C. Caption
4 MTS with dbx
5 Bass, Treble, Balance
6 Sub Audio Program
7 Remote hand unit Regu.
8 Nbr of RMT Button 29key
9 LED Indicators (P)
10 Local Keys 8key
11 Front Surround –
12 Sub Bass System
13 Audio Output 5W x 2
14 Speaker Size & Nbr 80 x 120 x 2
15 Comb Filter (GLS)
16 Black Level Expand –
17 Horizontal Resolution 500
18 Parental-Ch Lock
19 Channel Caption –
20 Off Timer (180min)
21 Channel Search –
22 S-Video In-Term (1)
23 Audio, Video In-Term (1)
24 Variable Audio Out (RCA Jack)
25 RGB Audio (L, R)
26 Mini D-Sub 15pin
27 Rod-Ant/Adapter –/–
NEW
SOUND
PICTURE
OTHER
CABINET
TERM

1-8
MM20E45 PC BOARD CONSTRUCTION
ITEM MM20E45 NEW MODEL CIRCUIT NOTE
DEF
PB5227
POWER/VCD
PB5226
SIGNAL/
VIDEO
PB5228
Def.
PB5227
(249.0 x 330.0)
Power/Audio
PB5226-1
(153.0 x 317.0)
Video/Chroma/Def
PB5226-2
(96.0 x 160.0)
Signal
PB5228-1
(110.0 x 330.0)
Video (CRT/D)
PB5228-2
(119.0 x 210.0)
D-Sub
PB5228-3
(28.5 x 41.5)
Printed wiring board
part code
P/P-M/P:
23534680B
Printed wiring board
part code
P/P-M/P:
23534679B
Printed wiring board
part code
P/P: 23534681B
M/P: 23534681C
249 x 330
dro
p
Hole draw-
ing: New Hole drawing: New
249 x 330
Hole drawing: New
249 x 330
Hole drawing: New
SIGNAL
VIDEO
V
-
CUT LINE
drop
D-SUB
Hole draw-
ing: New
POWER
V-CUT LINE
V/C/D
drop
Hole draw-
ing: New

2-1
SECTION II CHANNEL SELECTION CIRCUIT
1. OUTLINE OF CHANNEL SELECTION
SYSTEM
ThechannelselectioncircuitintheN5MM1chassisemploys
abussystemwhichperformsacentralcontrolbyconnecting
a channel selection microcomputer to a control IC in each
circuit block through control lines called a bus.
InthebussystemwhichcontrolseachIC,theI2C-bussystem
(two line bus system) promoted by Philips Co., Ltd. in the
Netherlands has been employed.
TheICscontrolledbytheI2C-buscontrolsystemare:ICG01
for audio system process, ICA02 for non-volatile memory,
H001 for main U/V tuners, IC302 for deflection distortion
corrections.
2. OPERATION OF THE CHANNEL
SELECTION CIRCUIT
2-1 Channel Selection Control Microcomputer
(ICA01 Toshiba TMP87CM34N-3101)
8 bit microcomputer, TLCS-870 series for TV receivers,
TMP87CM34N(42pins,built-inCCD)developedbyToshiba
is employed. With this microcomputer each IC and circuit
shown below are controlled.
2-1-1 Non-volatile Memory IC
(ICA02 NEC µPD672CX)
(1) Memorizes data for video and audio signal adjustment
values,soundvolume,wooferadjustmentvalue,external
input status, etc.
(2) Memorizesadjustmentdataforwhitebalance(RGBcut
off, GB drive), sub-brightness, sub color, sub-tint, etc.
(3) Memorizes deflection distortion correction value data
adjusted for each unit.
2-1-2 U/V Tuner Unit
(H001 Toshiba EL911L)
(1) A desired station can be received by transferring a
channel selection frequency data (division data) to the
I2C-bus type frequency synthesizer provided in the
tunerandbysettingabandswitchdatawhichselectsthe
UHF or VHF band.
2-1-3 Deflection Distortion Correction IC
(IC302 Toshiba TA8859AP)
(1) Sets adjustment memory values for vertical amplitude,
linearity,horizontalamplitude,parabola,corner,pedestal
distortion, etc.
2-1-4 Audio System Process IC
(ICG01, SONY CXA1784S)

2-2
3. SYSTEM BLOCK DIAGRAM
VIDEO SIGNAL
PROCESS CIRCUIT
A/V DSP UNIT
KEY SWITCH
RGB MODE
DISCRIMINATION
RELAY DRIVE
SYNC SEPA.
REMOTE
CONTROLLER LIGHT
ERCEPTION UNIT
PICTURE
CONTROL
AUDIO
CONTROL
TUNER/IF
DAC1
DAC2
5
6
7
STB
CLK
DATA
9
AFT
37
38
SCL
SDA
Y
B
G
R
25
24
23
22
MEMORY
µPD6272CX
QA02
DPG
MTS
H. PULSE
V. PULSE
6.13 MHz
TRF1147T
8MHz CLOCK
TCR1056
26
27
28
29
31
32
33
34
42
21
HD
VD
OSC1
OSC0
X1
X0
RST
HOLD
VDD
VSS
RESET
CIRCUIT,
5V
GND
35
36 RMT
SYNC
1RELAY
15 MODE
13
14
KEY A
KEY B
10 EXIT A
QA01
TMP87CM34N-3101

2-3
3-1 Microcomputer Terminal Name and Operation Logic
Terminal No. Terminal name I/O control resistor
1 RELAY Positive logic
2 P.B
3
4 MUTE Positive logic
5 STB T BUS PERIOD
6 CLK T BUS CLOCK
7 DATA T BUS DATA
8 I-CSTOP Negative logic
9 AFT
10 EXTA TV: H VIDEO/RGB: L
11 SPKOFF Negative logic
12 LINE21
13 KEY1 Local key input 0~5V
14 KEY2 Local key input 0~5V
15 MODE RGB MODE input 0~5V
16
17 Y IN
18 B IN
19 G IN
20 R IN
21 VSS GND
22 R
23 G
24 B
25 Y
26 HD H sync pulse input
27 VD V sync pulse input
28 OSC1
29 OSC0
30 TEST For microcomputer shipping test. Fixed low level
31 X IN
32 X OUT
33 RESET Negative logic
34 STOP Negative logic
35 RMT Remote controller signal det. Negative logic
36 SYNC Sync pulse signal input
37 SCL I2C BUS CLOCK
38 SDA I2C BUS DATA
39 TC1 GND
40 CSIN
41 VIN
42 VDD Microcomputer power supply
Oscillation connection terminal for OSD circuit
6.13MHz TRF1147T
High frequency oscillation connection terminal
Part for caption

2-4
3-2 DAC Terminal Name and Operation Logic
(1) DAC (QX01)
Terminal No. Terminal name Function I/O Logic
1 VDD INTERFACE POWER SUPPLY
2 DAT T-BUS DATA INPUT TERMINAL I
3 CLK T-BUS CLOCK INPUT TERMINAL I
4 PRD T-BUS PERIOD INPUT TERMINAL I
5 RESET
6 SUB-ADDRESS CHANGEOVER TERMINAL O
7 RGB CONT RGB CONTRAST O 0~5V
8 VSS GND
9 SBS SUB BASS SYSTEM O ON: L OFF: H
(H at SPK OFF)
10 RGB BRT RGB BRIGHTNESS O 0~5V
11 TNT TINT O 0~5V
12 COLOR COLOR O 0~5V
13 SHARP SHARPNESS O 0~5V
14 BRT BRIGHTNESS O 0~5V
15 CONT CONTRAST O 0~5V
16 VCC POWER SUPPLY
(2) DAC (QX001)
Terminal No. Terminal name Function I/O Logic
1 VDD INTERFACE POWER SUPPLY
2 DAT T-BUS DATA INPUT TERMINAL I
3 CLK T-BUS CLOCK INPUT TERMINAL I
4 PRD T-BUS PERIOD INPUT TERMINAL I
5 RESET
6 SUB-ADDRESS CHANGEOVER TERMINAL O
7 TV/RGB TV/RGB SWITCH TERMINAL O TV: L RGB: H
(L at RGB NO SIG.)
8
9 MUTE VIDEO MUTE O NEGATIVE LOGIC
10 H-POS H-POSITION O 0~5V
11 H-SIZ H-SIZE O 0~5V
12 V-POS V-POSITION O 0~5V
13 TV/RGB TV/RGB SWITCH TERMINAL O TV: H RGB: L
14 NO SIG NON/YES SIGNAL OUTPUT O YES: H NON: L
15 SUB CONT SUB CONTRAST (TV) O 0~5V
16 VCC POWER SUPPLY

2-5
3-3 Remote Control Code Assignment
Custom codes are 40H.
Key
No. Data code Function Conti-
nuity
K1 00H 0
K2 01H 1
K3 02H 2
K4 03H 3
K5 04H 4
K6 05H 5
K7 06H 6
K8 07H 7
K9 08H 8
K10 09H 9
K11 0AH 100
K12 0BH
K13 0CH RESET
K14 0DH AUDIO
K15 0EH PIC
K16 0FH RGB/TV/VIDEO
K17 10H MUTE
K18 11H
K19 12H POWER
K20 13H MTS
K21 14H OPTION
K22 15H TIMER
K23 16H SET UP
K24 17H CH RTN
K25 18H
K26 19H CONTROL UP
K27 1AH VOL UP
K28 1BH CH UP
K29 1CH RECALL
K30 1DH CONTROL DN
K31 1EH VOL DN
K32 1FH CH DN
K33 40H
K34 41H
K35 42H
K36 43H
K37 44H
K38 45H
K39 46H
K40 47H
K41 48H
K42 49H
K43 4AH
K44 4BH
K45 4CH
K46 4DH
K47 4EH
K48 4FH
Key
No. Data code Function Conti-
nuity
K49 50H
K50 51H
K51 52H
K52 53H
K53 54H
K54 55H
K55 56H
K56 57H
K57 58H EXIT
K58 59H
K59 5AH SET UP
K60 5BH OPTION
K61 5CH
K62 5DH
K63 5EH
K64 5FH
K88 97H
K109 CCH
K110 CDH
K111 CEH
K112 CFH

2-6
3-4 Local Key Assignment
1. Detection method of Local Key
Detection method of Local Key in N4ES chassis is analogue way to detect what voltage appears at local key input terminals
(pins 13, 14) of Micom when the key is pressed.
Bythismethod,keydetectionsofamaximumof7keyscanbedone,usinglocalkeyinputterminal(pin13).AsseenintheLocal
keycircuitbelow,whenoneof keyamongS13-1 toS13-7is pressed,theVIN whichcorrespondstotheswitchisappliedtoinput
terminal (pin 13). Judgement of key-input is done by measuring what voltage VIN is at the pin. Voltage measuring and key
judgement are performed by A/D converter in Micom and by the software.
KEY No. Function
S13-1 POWER
S13-2 CH UP
S13-3 CH DN
S13-4 VOL UP
S13-5 VOL DN
S13-6 ADV
S13-7 MENU
S14-1 RGB/TV/VIDEO
LOCAL KEY Assignment table
33K KEY1 KEY2
33K
7.5K
7.5K
11K
16K
30K
68K
S13-7
S13-6
S13-5
S13-4
S13-3
S13-2
S13-1 S14-1
13 14

2-7
4. I2C BUS INTERFACE OPERATION TIMING
As an example of I2C Bus interface operation timings,
control for a memory IC will be shown below.
4-1 Write Mode (1 Byte)
Slave address
Start bit issue
ACK signal
output
Word address
input
Word address
update
Stop bit issue
After completion of write operation
word address becomes the write
address +1 and held at that value.
S
DA
S
CL
1
0A
2
10A
1
52436
R/W ACK(OUT)
WA
7WA 6WA 5WA 4WA 3WA 2WA 1WA 0
789
ACK(OUT)
D
7D 6D 5D 4D 3D 2D 1D 0
ACK(OUT)
INININ
Slave address
R/W command input
100
ACK signal
output
ACK signal
output
Write data
input
Fig. 2-1
4-2 Read Mode
SDA
SCL
Start bit issue
ACK signal
output
Word address
input
R/W ACK(OUT)
0A
2
1A
1
0
1
152436789
ININ
WA
7
WA
6
WA
5
WA
4
WA
3
WA
2
WA
1
WA
0
0A
2
1A
1
100
R/W
ACK(OUT)
D
7
D
6
D
5
D
4
D
3
D
2
D
1
D
0
ACK(IN)
IN OUT IN
152436789
ACK signal
input
Read data
output
ACK signal
out
p
ut
Slave address
R/W command input
Start bit issue
ACK signal
input
Slave address
R/W command input
00
Stop bit issue
Fig. 2-1

2-8
4-2-1 Generation of Start/stop Status
Fig. 2-3
4-3 I2C Bus Data Format
(1) Memory IC
* Write mode
SSlave address
8 bits RW AC Word address
8 bits Data 8 bits AC ST
AC
* Read mode
SSlave address
8 bits RW AC Word address
8 bits Data 8 bits AC ST
AC Slave address
8 bits AC
(2) DPC IC
SSlave address
8 bits RW AC Data 8 bits AC ST
AC
Sub-address
8 bits
A0H (WRITE)
8CH
SCL terminal
S
DA termianl
Start
condition Data transmission
Acknowledge
signal
Stop
condition
SCL terminal
SDA termianl
152637489
D7 D6 D5 D4 D3 D2 D1 D0

2-9
(3) U/V tuner unit
SRW AC AC ST
AC
Slave address
8 bits
FM
8 bits
FL
8 bits
CO
8 bits
AC AC BA
8 bits
Main screen tuner: COH
FM: Variable divider control byte
FL: Variable divider control byte
CO: Charge pump sensitivity switching bit and test mode bit
BA: Band switching bit

2-10
5. SERVICE ADJUSTMENT MODE
1. Entering to Service Adjustment mode
Press MUTE key on the remote control unit once.
Press again the MUTE key, and keep pressing it.
Keep pressing the MUTE key, press MUTE key on TV set.
Adjusting picture of NTSC mode
120H 8DH
RGB 350
120H 8DH
Adjusting picture of RGB mode
2. Switch-over of Service Adjustment mode
EverypressingofMENUkeymakesmainaddressswitch
over.
161H 1E2H 120H 114H
4. Adjusting method of data
Pressing ADJUST UP/DOWN key on remote control
unit changes the data value ranging from 00H to FFH.
5. Cancellation method of Service mode
The operation of key that accompanies display of
other than from 1 to 4 makes the mode cancel.
During servicing in RGB mode, changing of the
mode of RGB causes cancellation.
6. Other service function
MUTE key : Shipping-out preset
RECALL key: Initializing of memory
Address Adjustment contents
161H Video section sub-adjustment
1E2H OSD horizontal starting position
120H Deflection section sub-adjustment
114H Multi-sound adjustment
3. Switch-over within Service Adjustment mode
PressingofVOLUPkeyonremotecontrolunitoronTV
set makes address switch over cyclically, and VOL DN
key switches over in reverse direction.
a) 161H 107H 163H 108H
b) 1E2H
c) 120H 121H 122H 123H 125H 126H
127H 128H 12AH 111H 112H
d) 114H 115H 116H 116H 117H 118H
119H
Address, Data
Mode display of RGB