Akai 21CTU91BC, 21CTU93BC, 21CTU94BC Schematic

CRT COLOR TV SET

21CTU93BC

SERVICE MANUAL

AKAI 21CTU93BC

This manual is the latest at the time of printing, and does not
include the modification which may be made after the printing, by
the constant improvement of product

- Content ......................................................................................................................... 2

- Bill of Materials ............................................................................................................. 3

- Safety Precautions ....................................................................................................... 7

- TV Block Diagram ......................................................................................................... 8

- Replacement Of Memory IC ......................................................................................... 10

- Service Adjustment ...................................................................................................... 10

- ICs Functional Description .......................................................................................... 18

- Test point Waveforms .................................................................................................. 22

- Purity / Convergence Adjustment ............................................................................... 23

- Explore View Diagram .................................................................................................. 25

SER DESCRIPTION QTY

PCB NO.

CABLE & SOCKET

1 AV6-14 1 XS801
2 CH5B-2.5-2DY 3 XS601 XS602 XS702
3 CH5B-2.5-4DY 4 XS403 XS703 XS704 XS804
4 CH5B-2.5-5DY 1 XS201
5 CH7-10-1DY 1 K9N
6 CH7-10-2DY 2 XS501 XS502
7 CH7-8-10-4DY 1 XS402
8

CH9-2.5-2DY-400-CH5B-W (卧式)

9

CH9-2.5-4DY-400-CH5B-4W(卧式)(带屏蔽)

1 XS701

1 XS702
10 CH9-2.5-4DY-450-CH5B 1 XP902
11 CH9-2.5-4DY-550-CH5B 1 PA102
12 CH9-2.5-5DY-500-CH5B 1 XP901
13 H03VVH2-F0.75mmX2C (250MM) short power cord 1
14 Power cord (2200mm ) 1
15 RCA-106A (red) 1 AV3
16 RCA-106A (white) 1 AV2
17 RCA-106A (yellow) 1 AV1

CARBON RESISTOR

18

RT-1/2W-1KΩ-J

19

RT-1/2W-220KΩ-J

20

RT-1/2W-220Ω-J

21

RT-1/2W-22KΩ-J

22

RT-1/4W-1.8KΩ-J

23

RT-1/4W-150Ω-J

24

RT-1/4W-1KΩ-J

25

RT-1/4W-1Ω-J

26

RT-1/4W-2.2Ω-J

27

RT-1/4W-2.7KΩ-J

28

RT-1/4W-220KΩ-J

29

RT-1/4W-27Ω-J

30

RT-1/4W-33Ω-J

31

RT-1/4W-8.2Ω-J

32

RT-1/4W-82Ω-J

33

RT-1/6W-1.2K

34

RT-1/6W-1.5KΩ-J

35

RT-1/6W-1.8KΩ-J

36

RT-1/6W-100KΩ-J
RT-1/6W-100Ω-J

38

RT-1/6W-10KΩ-J

39

RT-1/6W-12KΩ-J

40

RT-1/6W-150KΩ-J

41

RT-1/6W-15KΩ-J

42

RT-1/6W-1KΩ-J

43

RT-1/6W-2.7KΩ-J

44

RT-1/6W-220KΩ-J

45

RT-1/6W-220Ω-J

46

RT-1/6W-22KΩ-J

47

RT-1/6W-27KΩ-J

48

RT-1/6W-3.3KΩ-J

49

RT-1/6W-3.9KΩ-J

50

RT-1/6W-330Ω-J

51

RT-1/6W-33KΩ-J

52

RT-1/6W-390Ω-J

53

RT-1/6W-39KΩ-J

54

RT-1/6W-39Ω-J

55

RT-1/6W-3KΩ-J

56

RT-1/6W-4.7KΩ-J

57

RT-1/6W-4.7Ω-J

58

RT-1/6W-470Ω-J

59

RT-1/6W-47KΩ-J

60

RT-1/6W-47Ω-J

61

RT-1/6W-5.1KΩ-J

62

RT-1/6W-680Ω-J

63

RT-1/6W-8.2KΩ-J

Ω-J

1 R403

1 R501

1 R564

1 R487

1 R507

1 R575

2 R406 R457

1 R302

1 R304A

1 R508

1 R401

1 R720

2 L201 R940

1 R511

1 R562

1 R105

1 R706

2 R301 R303

5 R313 R554 R716 R802 R837

R110 R111 R208 R209 R210 R212 R306 R307 R710 R711

1837

R712 R714 R715 R823 R824 R825 R826 R838
R109 R211 R576 R602 R611 R612 R614 R702 R723 R811

18

R812 R815 R817 R821 R836 R912 R922 R932A
1 R207
2 R605 R700
3 R725 R609 R610

R553 R558 R565 R566 R573 R713 R730 R803 R805 R816

13

R818 R820 R822
1 R705
2 R407 R226
6 R101 R309 R806 R913 R923 R933
2 R706 R221
2 R402 R701
3 R613 R703 R704
1 R704
3 R916A R926 R936
2 R205 R705
1 R201
4 R204 R222 R604 R603
1 R103
1 R559

R104 R108 R213 R311 R707 R709 R718 R719 R721 R727

13

R728 R703 R719A
1 R217
6 R102 R218 R219 R220 R312 R807
3 R106 R726 R606
6 R911 R914 R916 R924 R932 R934
1 R414
3 R202 R707 R719B
1 R702

CERAMIC CAPACITOR

64

CT-1KV-1000pF-K(湿封装）

2 C504 C505

65 CT-2KV-1000pF-K 1 C943
66 CT-2KV-471pF-K 1 C553
67 CT-2KV-680pF-K 2 C513 C511
68 CT-500V-1000pF-K 1 C452
69 CT-500V-3900pF-K 2 C451 C510
70 CT-63V-0.01uF-Z 9 C104 C105 C106 C216 C569 C612 C613 C701 C711
71 CT-63V-0.1uF-K 5 C220 C222 C223 C707 C713
72 CT-63V-1000pF-J 6 C202 C203 C205 C206 C213 C214
73 CT-63V-220pF-J 3 C313 C702 C703
74 CT-63V-390pF-J 3 C921 C931 C911
75 CT-63V-560pF-J 1 C225
76 CT7-2E4-400VAC-3300pF-M 1 C517

SER DESCRIPTION QTY

PCB NO.

COIL, IN,LF,TFM

77 130-208-0011 1 L405
78 3.0mH 1 L404
79 BCK-42-09936 1 T501
80 JBC-184-EI19/YDD-EI19 1 T451
81 JLC/YDD-600µH 1 L311
82 JLC-128-23µH 1 L441
83 LG0307-1.2UH-K 1 L101
84 LG0307-10UH-K 6 L202 L203 L701 L702 L703 L704
85 YDD-UF16/JLF-98-UF16 1 L501

DIODE

86 BAV21 3 D912 D922 D932
87 FR107 3 D301 D302 D401
88 FR154 2 D510 D513
89 FR157 1 D462
90 FR305/RU4C 2 D452 D559
91 FR309/RU4DS 1 D451
92 HER154/HER204 1 D553
93 HER204 3 D552 D554 D555
94 IN4148 8 D404 D461 D516 D558 D565 D566 D601 D701
95 IN5399/RL207 4 D501 D502 D503 D504
96 RU4A /RU4AM 1 D551

ELECTROLYTE CAPACITOR

97 CD110-160V-100UF-M 2 C403 C551
98 CD110-16V-100UF-M 5 C208 C219 C221 C224 C568

C101 C108 C102 C103 C204 C217 C708 C603 C710 C801

2199 CD110-16V-10UF-M

C802 C804 C805 C806 C807 C808 C809 C813 C814 C815

C816

100 CD110-16V-220UF-M 1 C211
101 CD110-16V-470UF-M 4 C566 C567 C609 C803
102 CD110-16V-47UF-M 6 C563 C564 C565 C709 C712 C701
103 CD110-250V-10UF-M 1 C459
104 CD110-25V-470UF-M 5 C314 C315 C555 C556 C601
105 CD110-35V-100UF-M 1 C304
106 CD110-35V-470UF-M 1 C305
107 CD110-35V-47UF-M 2 C401 C508
108 CD110-50V-0.22UF-M 2 C607 C608
109 CD110-50V-1UF-M 5 C218 C611 C605 C810 C811
110 CD110-50V-4.7UF-M 1 C561
111 CD288H-250V-10UF-M 1 C402
112 CD293-400V-150UF-M 1 C507
113 CD71-50V-10µF-M 1 C312

FBT

114 BSC25-0226Q 1 T401

GLASS ENAMEL RESISTOR

115

RI-1/2W-12MΩ-K

1 R514

HEATSINK

116 HS-EW04-60 1 V303
117 HS-PH01-50 1 V451
118 HS-PW01-50 1 N502
119 HS-VS02-70 1 N301
120 HS-WS03-40 1 N601

INTEGRATE CIRCUIT

121 5Q0765RF 1 N502
122 AT24C08/ATMEL24C08 1 N701
123 PC817B/LTV-817/817B 1 N501
124 STV9325/STV8172A 1 N301
125 TC4052/HEF4052BP 1 N801
126 TDA11136 1 N201
127 TDA7266SA 1 N601
128 TL431 1 V551
129 UPC574/KA33V 1 N561

JUMPERS

W214 W216 W402 W504 W505 W509 W510 W563 W591 W602

21130 10MM

W701 W702 W704 W712 W801 W802 W803 W804 W805 W806

L901

131 12.5MM 10 W502 W205 W204 W561 W593 W606 W709 W714 L301 L403
132 15MM 3 W551 R513 R568
133 17.5MM 2 W406 W405
134 5MM 4 W104 W215 C453 W807

W101 W102 W103 W201 W202 W203 W206 W207 W208 W209

W210 W211 W212 W403 W503 W506 W512 W513 W552 W601

31135 7.5MM

W603 W604 W605 W708 W710 W713 D557 R319 D911 D921

D931

LED

136

LED(red）

1 LED4

OTHER

137 BXGJ-1 2 F501
138 GZS10-108C 1 XS902
139 KDVF38.9H/F38.9H/LBN38.9H 1 Z101
140 PG-238 (INFRARED RECEIVER) 1 RE
141 T3.15A250V-AC 1 F501
142 X24.576M/T24.576M 1 G701

SER DESCRIPTION QTY

孔

143

贴于场IC

144

贴于电源管

PCB NO.

1
1

OXIDE FILM RESISTOR

145

RF-2W-1.5Ω-J

146

RY-1/2W-120KΩ-J

147

RY-1/2W-2.7KΩ-J

1 R451
3 R503 R504 R555
3 R918 R928 R938

148 RY-1/6W-39K-G 1 R206
149
150
151
152
153
154
155
156
157
158
159
160

RY-1W-180Ω-J
RY-1W-1KΩ-J
RY-1W-1Ω-J
RY-2W-0.47Ω-J
RY-2W-12KΩ-J
RY-2W-15KΩ-J
RY-2W-2.2Ω-J
RY-2W-270Ω-J
RY-2W-4.7Ω-J
RY-2W-47KΩ-J
RY-2W-5.6Ω-J
RY-2W-8.2Ω-J

1 R305
1 R404
1 R304
1 R601
3 R915 R925 R935
1 R569
1 R561
1 R454
1 R567
1 R512
1 R317
1 R571

PCB

161 IU-2103KY-001 1
162 IU-2103RE-001 1
163 IVPH-002/21 ver1.1 1
164 JS02-3AV-14 VER1.2 1

POLYESTER CAPACITOR

165 CL11-100V-0.0047uF-K 1 C522
166 CL11-100V-0.0068uF-K 1 C215
167 CL11-100V-0.015uF-K 1 C301
168 CL11-100V-0.033uF-K 3 C404 C519 C559
169 CL11-100V-0.047uF-K 2 C302 C310
170 CL11-100V-0.1uF-K 8 C201 C209 C303 C458 C704 C705 C706 C520

POLYPROPYLENE CAPACITOR

171 CBB21-250V-0.22uF-J 1 C461
172 CBB21-400V-0.3uF-K 1 C460
173 CBB21-630V-0.027uF-K 1 C457
174 CBB21-630V-0.068uF-J 1 C462
175 CBB23A-250VAC-0.1µF-M 1 C501
176 CBB81-1.6KV-2200PF-K 1 C454
177 CBB81-1.6KV-8200pF-K 1 C456
178 CBB81-1.6KV-9100PF-K 1 C455
179 CL21X-63V-0.15uF-K 1 C207

POWER SWITCH

180 KDC-A04-001S 1

PTC & NTC THERMISTOR

181 8D-11 1 R502
182

MZ73-9Ω（3脚)

1 RT501

SCREWS

183 2.0 X 3.5MM 9

L441(短

T501(4) T401(3)
184 2.3 X 3.5MM 2 C507(2)
185 TR 3×10 (with pad) 3 V303 N601(2)
186 TR 3×10 (without pad) 3 N301 N502 V451

TACT SWITCH

187 KFC-A06-P5 6 SW1 SW2 SW3 SW4 SW5 SW6

TRIODE

188 2SA1015-Y 3 V563 V601 V803
189 2SC1674 1 V101
190 2SC1815-Y 9 V201 V202 V203 V311 V562 V602 V702 V801 V802
191 2SC2383 4 V401 V561 V564 V565
192 2SC2482 3 V911 V921 V931
193 2SC5296 1 V451
194 A940 1 V303
195 BF421/BF423 3 V913 V923 V933

TUNER

196 EWE-5053-V8/ET-5K1E-EV100K 1 A101

VARIABLE RESISTOR

197

W206-2AL20KΩ-K

1 RP551

ZENER DIODE

198 MTZJ3V3/3C2 1 D703
199 MTZJ3V6/4A2 1 D509
200 MTZJ5V1/5C2 2 D801 D802
201 MTZJ5V6/6B1 2 D567 D564
202 MTZJ8V2 1 D941
203 MTZJ8V2/9A2 1 D402
204 MTZJ8V7/9B2 1 D561

CE STANDARD COMPONENT

SER DESCRIPTION QTY

CERAMIC CAPACITOR

1

CT-1KV-1000pF-K(湿封装）
2 CT7-2E4-400VAC-2200pF-M +2 C515 C516
3 CT7-2E4-400VAC-3300pF-M -1 C517

COIL, IN,LF,TFM

PCB NO.

+2 C503 C506

SER DESCRIPTION QTY

4 F22-22R0-031000/JLF-148-ET24 +2 L501 L502
5 YDD-UF16/JLF-98-UF16 -1 L501

JUMPERS

6 10MM -2 W509 W510

POLYPROPYLENE CAPACITOR

7 CBB23A-250VAC-0.1µF-M -1 C501
8 CBB23A-250VAC-0.1µF-M +1 C512
9 CBB23A-250VAC-0.22µF-M +2 C501 C502

PCB NO.

SAFETY PRECAUTIONS

1. The design of this product contains special hardware, many
circuits and components specially for safety purposes. For
continued protection, no changes should be made to the
original design unless authorized in writing by the
manufacturer. Replacement parts must be identical to those
used in the original circuits. Service should be performed by
qualified personnel only.

2. Alterations of the design or circuitry of the products should
not be made. Any design alterations or additions will void
the manufacturer’s warranty and will further relieve the
manufacturer of responsibility for personal injury or property
damage resulting therefrom.

3. Many electrical and mechanical parts in the products have
special safety-related characteristics. These characteristics
are often not evident from visual inspection nor can the
protection afforded by them necessarily be obtained by
using replacement components rated for higher voltage,
wattage, etc. Replacement parts which have these special
safety characteristics are identified in the parts list of
Service manual. Electrical components having such

features are identified by shading on the schematics
and by ( ！ ) on the parts list in Service manual. The use

of a substitute replacement which does not have the same
safety characteristics as the recommended replacement
part shown in the parts list of Service manual may cause
shock, fire, or other hazards

4. Don’t short between the LIVE side ground and

ISOLATED (NEUTRAL) side ground or EARTH side
ground when repairing. Some model’s power circuit is

partly different in the GND. The difference of the GND is
shown by the LIVE: ( ) side GND, ISOLATED (NEUTRAL) :
( ) side GND and EARTH : ( ) side GND. Don’t short
between the LIVE side GND and ISOLATED (NEUTRAL)
side GND or EARTH side GND and never measure with a
measuring apparatus (oscilloscope etc.) the LIVE side GND
and ISOLATED (NEUTRAL) side GND or EARTH side GND
at the same time. If above note will not be kept, a fuse or
any parts will be broken.

5. If any repair has been made to the chassis, it is
recommended that the B1 setting should be checked or
adjusted (See ADJUSTMENT OF B1 POWER SUPPLY).

6. The high voltage applied to the picture tube must conform
with that specified in Service manual. Excessive high
voltage can cause an increase in X-Ray emission, arcing
and possible component damage, therefore operation under
excessive high voltage conditions should be kept to a
minimum, or should be prevented. If severe arcing occurs,
remove the AC power immediately and determine the cause
by visual inspection (incorrect installation, cracked or melted
high voltage harness, poor soldering, etc.). To maintain the
proper minimum level of soft X-Ray emission, components
in the high voltage circuitry including the picture tube must
be the exact replacements or alternatives approved by the
manufacturer of the complete product.

7. Do not check high voltage by drawing an arc. Use a high
voltage meter or a high voltage probe with a VTVM.
Discharge the picture tube before attempting meter
connection, by connecting a clip lead to the ground frame
and connecting the other end of the lead through a 10kΩ
2W resitor to the anode button.

8. When service is required, observe the original lead dress.
Extra precaution should be given to assure correct lead
dress in the high voltage circuit area. Where a short circuit
has occurred, those components that indicate evidence of
overheating should be replaced. Always use the

9. manufacturer’s replacement components.

.

10. Isolation Check

(Safety for Electrical Shock Hazard)

After re-assembling the product, always perform an isolation
check on the exposed metal parts of the cabinet (antenna
terminals, video/audio input and output terminals, Control
knobs, metal cabinet, screwheads, earphone jack, control
shafts, etc.) to be sure the product is safe to operate without
danger of electrical shock.

11. The surface of the TV screen is coated with a thin film which
can easily be damaged. Be very careful with it when handle
the TV. Should the TV screen become soiled, wipe it with a
soft dry cloth. Never rub it forcefully. Never use any cleaner
or detergent on it.

(1) Dielectric Strength Test

The isolation between the AC primary circuit and all metal
parts exposed to the user, particularly any exposed metal
part having a return path to the chassis should withstand a
voltage of 3000V AC (r.m.s.) for a period of one second.
(…Withstand a voltage of 1100V AC (r.m.s.) to an appliance
rated up to 120V, and 3000V AC (r.m.s.) to an appliance
rated 200V or more, for a periode of one second.)
This method of test requires a test equipment not generally
found in the service trade.

(2) Leakage Current Check

Plug the AC line cord directly into the AC outlet (do not use
a line isolation transformer during this check.). Using a
“Leakage Current Tester”, measure the leakage current
from each exposed metal part of the cabinet, particularly
any exposed metal part having a return path to the chassis,
to a known good earth ground (water pipe, etc.). Any
leakage current must not exceed 0.5mA AC (r.m.s.).
However, in tropical area, this must not exceed 0.2mA AC
(r.m.s.).

●Alternate Check Method

Plug the AC line cord directly into the AC outlet ( do not use
a line isolation transformer during this check.). Use an AC
voltmeter having 1000 ohms per volt or more sensitivity in
the following manner. Connect a 1500Ω 10W resistor

paralleled by a 0.15μ F AC-type capacitor between an
exposed metal part and a known good earth ground (water
pipe, etc.). Measure the AC voltage across the resistor with
the AC voltmeter. Move the resistor connection to each
exposed metal part, particularly any exposed metal part
having a return path to the chassis, and measure the AC
voltage across the resistor. Now, reverse the plug in the AC
outlet and repeat each measurement. Any voltage
measured must not exceed 0.75V AC (r.m.s.). This
corresponds to 0.5mA AC (r.m.s.).
However, in tropical area, this must not exceed 0.3V AC
(r.m.s.).
This corresponds to 0.2mA AC (r.m.s.)

7

TV Block diagram

VoV

A

A

A

A

A

V24V

V8V5V

V

Y

V

N

S

A

ALoA

A

2

V

V

TUNER

POWER

UNIT

SAW

video

24C08

bus

130

+13

-13

3.3

TDA11105-XXXX

IF IN R IN

RF AGC GIN

B IN

CHROMA
VIDEO
CVBS/Y IN

CVBS1 IN
CVBS2 IN

SDA
SCL MA IN L
MAOUTR MA IN R
MAOUTL
RGB OUT
V OUT H OUT

V IN

TDA8177

V OUT

D

H IN

H OUT

H OUT

200

CRT PCB

SCREE

FOCU

audio

8

.

video

R
G

B

405

video

Video IN

audio

audio

CRT

C

R i1

Li 1

Ro

Ri 2
Li 2

video

2i

Li2

Li1

N17821

Vi1

OUT1-

OUT1+

Vi2

OUT2-

OUT2+

8