Casio ev2500ci schematic
(with price)
INDEX
EV-2500C/I/N (KX-618C/I/N)
JUL. 1995
R
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CONTENTS
SPECIFICATIONS ......................................................................................... 2
BLOCK DIAGRAM ........................................................................................ 3
CIRCUIT DESCRIPTION ............................................................................... 4
DISASSEMBLY ............................................................................................. 5
DIAL STRINGING DIAGRAM........................................................................ 6
ADJUSTMENT............................................................................................... 7
TROUBLESHOOTING................................................................................. 12
PRINTED CIRCUIT BOARDS ..................................................................... 13
EXPLODED VIEW ....................................................................................... 15
ELECTRICAL PARTS LIST......................................................................... 16
MECHANICAL PARTS LIST ....................................................................... 23
IC AND TRANSISTOR LEAD IDENTIFICATION ........................................ 25
SCHEMATIC DIAGRAMS ........................................................................... 27
WAVEFORMS.............................................................................................. 29
— 1 —
SPECIFICATIONS
Item Specification
1. Reception channels TV— EV-2500C/N: VHF: 2 ~ 12 ch UHF: 21 ~ 69 ch
EV-2500I : VHF: A ~ H2 ch UHF: 21 ~ 69 ch
RADIO— FM: 88~108 MHz AM: 530~1710 KHz
2. Power voltage DC 6.0 V
3. Power consumption Approx. 3.5 W
4. Current consumption Approx. 580 mA
5. Battery life (with alkaline batteries) Approx. 11 hours
Batteries : 3 D size batteries
6. Power supply Car adaptor : CA-K65
AC adaptor : AD-K65, 64
Earphone jack : 3.5ø mini
7. Connection terminals External power jack : 6.0 V DC IN
External antennea jack : 3.5ø mini
Audio / Video jack : 3.5ø
8. Screen size 2.5 inches
9. No. of picture element 61,380 (220 × 279) dots
10. Dimensions 115 (W) × 61.7 (D) × 112 (H) mm
4 1/2 (W) × 2 2/5 (D) × 4 2/5 (H)
11. Weight 360 g excepting batteries
12.7 oz excepting batteries
AC adaptor : AD-K65,64
12. Options Car adaptor : CA-K65
RF connector : CF-13
Antenna matching device : AS-35S
— 2 —
TV
Antenna
BLOCK DIAGRAM
Power
Supply
1 TU200 2 Q200
IF Amp.Tuner
7
IC270
Tuning
Voltage
Generator
VCC1 (4.5 ± 0.05 V)
VCC2 (4.5 ± 0.05 V)
VCC7 (25.9 ~ 31.3 V)
VCC6 (10.0 ~ 12.0 V)
VEE1 (–8.0 ~ –7.0 V)
VEE2 (–18.4 ~ –16.0 V)
3 IC200
Video
Sound Det.
FM
AFT Circuit
AGC Circuit
5
6
Det
IC300
Chroma
Circuit
IC700
Display
Control
Auto-Tuning
Control
4 IC600 Speaker
VR600
Audio
Amp.
Volume
Control
LCD
1 — Color tuner: TU200 TEPU5-02
Selects a desired radio wave and changes it to the video IF signal.
2 — Video IF amp.: Q200 2SC4238
Amplifies the video IF signal output from tuner TU200 by 10 times (20 dB).
3 — Video det./Sound det./FM det./AFT/AGC: IC200 M51348FP
Eliminates the carrier wave in the video IF signal, and picks up the video signal and the sound IF signal.
Also, the sound signal is picked up from the sound IF signal by FM detection.
4 — Audio amp.: IC600 NJM2070M
Sound amplification.
5 — Chroma circuit: IC300 IR3P90Y
Generates the tricolor (red, green, and blue) from the video signal.
6 — Display control/Auto-tuning control: IC700 MSM6770GS
Controls the display.
7 — Tuning voltage generator: IC270 BA10358F
Generates the tuning voltage with the tuning pulse output from 6.
— 3 —
POWER SUPPLY
CIRCUIT DESCRIPTION
VCC2-3 (4.5 V)
6.3 V 220C100
CP105
D100
R107
MA141K 33K B6800p
D110
2.2
C105
Q101
2SD1819A-R
MA3051-L
0R00
R100
BH102K
TM100
2K
VR100
270K
R108
Q110 2SD1819A-R
C137
C140
CH470p
3.3K
R105
270
R110
Q111
2SD1119-R
R115
100
2.2KR113
C145
2
1
9
B1500p
6
T100
LC12U-35
CP106
GND
Figure 1
D158 MA143A
3
C146
4
D156 MA141K
1
5
2
D154 MA142WK
6
D152
MA142WK
7
D150
MA142WK
8
OPEN
3
CP112
C110 25 V 10
R160
68
10SL6R8M
C112
C114 6SL 15M
L101
100u
L102
100u
C116 6.3 V 100
C118 16 V 22
VCC2-2 (4.5 V)
VCC7 (25.9 ~ 31.3 V)
CP110
VCC6 (10.0 ~ 12.0 V)
CP111
VCC2-1 (4.5 V)
CP113
VEE1 (-8.0 ~ -7.0 V)
CP114
VEE2 (-18.4 ~ -16.0 V)
CP115
C120 35 V 22
R161 33K
The power supply consists of a DC-DC converter and the associated circuit and supplies the voltages as shown
in Table 1.
Name Voltage Function
VCC2-1 4.50 ± 0.02 V Main voltage
VCC7 25.9 ~ 31.3 V Tuning voltage
VCC6 10.0 ~ 12.0 V Display voltage
VEE1 –8.0 ~ –7.0 V Display voltage
VEE2 –18.4 ~ –16.0 V Display voltage
Table 1
— 4 —
DISASSEMBLY
1. Remove the battery case.
2. Remove the three screws and the lower case.
3. Remove the three knobs.
4. Remove the screw and resolder the two wires for the speaker.
5. Remove the PCB ass'y.
— 5 —
Sliding pointer
9
1
0.8 mm
DIAL STRINGING DIAGRAM
Turn the pulley counterclockwise.
2
0
3
8
4
A
5
7
6
Wrap around 4 times.
— 6 —
ADJUSTMENT
TV
Items to Be Adjusted
Item Measuring Instrument
VCC2-1 voltage setting Voltmeter
Video detection coil adjustment TV signal generator, pattern generator, oscilloscope,
low-pass filter
AFT coil adjustment Sweep generator, oscilloscope, voltmeter
Contrast adjustment TV signal generator, pattern generator, oscilloscope
Tint adjustment TV signal generator, pattern generator, oscilloscope
AGC adjustment TV signal generator, pattern generator, IF levelmeter
Vcom adjustment Photo diode, photo sensor amp., bandpass filter, oscilloscope
Free-Running frequency adjustment
Frequency counter
RADIO
When the radio is defect, replace the radio PCB unit.
Adjustment and Test Point Locations
T201
T200
VR740
VR200
VR303
T300
Top View
— 7 —
VR300
VR100
IF Pad
TP2 (CP201)
TP7 (CP208)
TP8 (CP334)
TP5 (CP339)
TP6 (CP322)
Bottom View
Equipment Connection / Adjustment Procedure
VCC2-1 Voltage Setting
TP4 (CP217)
TP3 (CP218)
TP1 (CP113)
EV-2500
16-169
set
Output
TP1
Input Input Input Output Output
Connection Point Signal Connection Point
Adjust Result
VR100
Voltmeter
— 8 —
Voltmeter
TP1
Adjust to obtain a 4.50 ± 0.02 V
reading on the voltmeter.
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