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Content General… … … … … … … … … … … … … … … … … … … … … … … … … … … … … 2 Brief Introduction… … … … … … … … … … … … … … … … … … … … … … … … ..3 Software Description… … … … … … … … … … … … … … … … … … … … … … ..4 Circuit Description… … … … … … … … … … … … … … … … … … … … … … … ..8 CPU Pins… … … … … … … … … … … … … … … … … … … … … … … … … … … … 12 Part List 1… … … … … … … … … … … … … … … … … … … … … … … … … … … ..14 Adjustment Description… … … … … … … … … … … … … … … … … … … … … .26 Troubleshooting chart… … … … … … … … … … … … … … … … … … … … … … 29 Disassembly and Assembly… … … … … … … … … … … … … … … … … … ..42 Exploded View… … … … … … … … … … … … … … … … … … … … … … … … ..45 Part List 2… … … … … … … … … … … … … … … … … … … … … … … … … … … .46 Packing… … … … … … … … … … … … … … … … … … … … … … … … … … … … ..48 PC Board View… … … … … … … … … … … … … … … … … … … … … … … … … .49 Block Diagram… … … … … … … … … … … … … … … … … … … … … … … … … ..50 Schematic Diagram… … … … … … … … … … … … … … … … … … … … … … ..51 Specifications… … … … … … … … … … … … … … … … … … … … … … … … … 52
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TC- 446 Service Manual
General Manual Scope This manual is intended for use by experienced technicians familiar with similar types of communication equipment. It contains all service information required for the equipment and is current as of the publication date.
User Safety Information The following precautions are recommended for personnel safety: DO NOT transmit until all RF connectors are verified secure and any open connectors are properly terminated. SHUT OFF and do not operate this equipment near electrical blasting caps or in an explosive atmosphere. When in vehicles with an airbag, do not place a portable radio in the area over an airbag or in the airbag deployment area. Do not expose the radio to direct sunlight for a long time nor place it close to a heating source. Do not use any portable radio with a damaged antenna. If a damaged antenna comes into contact with your skin, a minor burn may result. When transmitting with a portable radio, hold the radio in a vertical position with its microphone about 5 centimeters away from your mouth. If you wear a portable radio on your body, be sure to keep the antenna at least 2.5 centimeters away from your head or body when transmitting. This equipment should be serviced by qualified technicians only.
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TC- 446 Service Manual
Brief Introduction
(2)
(3)
(4)
(1)
(12) (8)
(5)
(9)
(11)
(6) (7)
(10) (13)
1. Antenna 2.
LED indicator The light will glow red during transmission. The light will glow green during receiving. During
transmission, the light flashes red when the battery voltage is low. 3. Channel selector knob Turn the channel selector knob to select from channels 1-16 (Channel 16 can be programmed by your dealer as scan function). 4. Power/Volume control knob Rotate the Power/Volume Knob clockwise until a “click”is heard to turn the radio on, fully counter clockwise until a “click”is heard to turn the radio off. When the radio is on, turn the knob to adjust volume. 5. PTT key Press and hold PTT key to talk, release to receive. 6. Monitor key In receive mode, long press (above 2 seconds) Monitor key to monitor activity on the current channel. 7. Microphone 8. Speaker 9. External jack Remove the jack cover and insert an earphone; or insert programming cable into the jack to programme the radio via programming software. 10. Battery 11. Belt clip Used to clip radio on your belt. 12. Battery latch Used to fasten and remove the battery. 13. Charging connectors Connect the charging connectors with that on the charger to begin charging.
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TC- 446 Service Manual
Software Specification Radio Feature Description 1.
Use channel selector knob to choose from 15+1(Scan) channels
2.
Monitor
3.
CTCSS/CDCSS Non-standard Model (Other): 38+83 groups
4.
Channel Spacing 12.5KHz Narrow Optional
5.
Channel Scan (Priority channel and scan revert channel available)
6.
Battery Save feature (Dealer programmable)
7.
Time-out Timer (TOT)
8.
Squelch Level Control (9 levels)
9.
Low Battery Alert
10. Model Set Mode 11. PC Programming and Adjusting Mode 12. User Wired Clone Mode 13. Factory Wired Clone Mode 14. Manual Adjust Mode
1.
Radio Modes User Mode: User mode is conventional communication mode. Turn the power on while disconnecting the two SELF points, the radio enters user mode. (Refer to “TC-446 Owner’ s Manual”for details about operation in this mode.)
2.
Model Set Mode
(1) If the radio is standard model, short out the two MS2 points on PCB and then operate following the steps (3) (5) and (6). If the radio is non-standard model, please disconnect the two MS2 points on PCB and then operate the following steps. (2) To select MS1 (See the initial data table) according to the radio model, if MS1 is 1, short out the two MS1 points on PCB and continue the following operation. If not, disconnect the two MS1 points and continue. (3) Short out the two SELF points on PCB and then turn the power on. Two beeps sound. (4) Turn channel selector knob to the corresponding position (1-11) according to the radio model (Refer to the initial data table). (5) Press PTT key while holding down MONI key to set the model. Channel data and settings are initialized (Refer to the initial data table). (6) Turn off the power and then disconnect the two SELF points on PCB to complete the model setting. Take TC-446 (446.00625~446.09375MHz) as example. From the initial data table, it is of standard model. To initialize its model and channel data, you can operate as following: (1) Short out the two MS2 points on PCB; (2) Short out the two SELF points. Power on and two BEEP sounds will be heard. (3) Press PTT key while holding down MONI key. Channel data and settings are initialized (refer to the initial data table).
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TC- 446 Service Manual (4) After data reset, turn off the power, disconnect the two SELF points and restart the power to use the radio. Remarks: The old data (frequency, CTCSS/CDCSS, channel function settings) will be changed once the model is set, and part of functions will also be changed. Therefore, do not make this operation unless it’ s very necessary, such as changing the EEPROM, etc. 3.
PC Programming Mode The following parameters can be set through programming software:
（1） Receive frequency and transmit frequency （2） Receive signaling and transmit signaling （3） Busy channel lockout （4） Time-out timer （5） Squelch level （6） Battery save （7） Audio alarm （8） Monitor mode （9） Scan mode （10） Scan revert channel （11） Priority scan channel （12） N/W Model （13） low power （14） N setting
4. PC Adjusting Mode The following parameters can be set via PC programming software: (1)
Low battery alert level
(2)
Squelch level 9
(3)
Squelch level 3
(4) CTCSS deviation (narrow) (5)
CDCSS deviation (narrow)
5. Manual Adjust Mode If manual adjust mode is enabled, turn on the power while holding down PTT and MONI simultaneously, the radio enters manual adjust mode after 2 seconds. Choose the adjusting items by turning the channel selector knob to CH1-CH5 position; use PTT (upwards) or MONI (downwards) to adjust (Note: MIC jack shouldn’ t be connected with external cable while adjusting), CH1-CH5 positions are defined as follows: (1)
Low battery alert level
(2)
Squelch level 9
(3)
Squelch level 3
(4)
CTCSS deviation (narrow)
(5)
CDCSS deviation (narrow)
Note: To enable or disable manual adjust mode: short out the two SELF points, turn on the power to enter model set mode. And then the manual adjust mode is enabled. Press [PTT], manual adjust mode is disabled. This mode is suggested to be disabled after the adjustment is completed.
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TC- 446 Service Manual
6. User/Factory Wired Clone Mode Turn on the power while holding down MONI, the radio enters wired clone mode. (1) If the two SELF points are disconnected, press MONI again to begin user wired clone and red LED blinks; When cloning is completed, red LED goes out. (2) If the two SELF points are short circuit, press MONI again to begin factory wired clone and red LED blinks; When cloning is completed, red LED goes out. Note: The difference between user wired clone mode and factory wired clone mode is that the latter is able to clone tune parameters.
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TC- 446 Service Manual Initial data table MS1
Model
1CH Frequency (MHz)
Standard
446.00625~446.09375 CH QT/DQT
IF (MHz)
-21.4
2CH
3CH
4 CH
5CH
6CH
7CH
8CH
9-16CH
(MHz)
Tx
Rx
Tx
Rx
Tx
Rx
(MHz)
(MHz)
(MHz)
(MHz)
(MHz)
(MHz)
(MHz)
(MHz)
(MHz)
(MHz)
(MHz)
446.00625
446.00625
446.05625
446.05625
446.03125
446.03125
446.08125
446.01875
446.06875
446.04375
446.09375
OFF
OFF
OFF
OFF
97.4
97.4
71.9
79.7
67
85.4
023
Note: For standard model, CTCSS is off in all channels after initialization.
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TC- 446 Service Manual
Circuit Description 1.
Frequency Configuration The receiver utilizes double conversion superheterodyne. The first IF is 21.4MHz and the second is 455KHz. The first local oscillator signal is supplied from PLL circuit. Frequency needed in the transmitter is supplied from PLL circuit. Figure 1 shows the frequency configuration. Frequency Range: 446.00625 MHz— 446.09375MHz
Figure 1 frequency configuration
2.
Receiver The receiver utilizes double conversion superheterodyne. 1) Front-end RF Amplifier The input signal from antenna is amplified in RF amplifier (Q27) after passing through the receive/transmit switch circuit and a 3-stage LC band pass f ilter. The amplified signals are filtered by a band pass filter (a 3-stage LC BPF) to eliminate unwanted signals before they goes to the first frequency mixer.
Figure 2 receiver section configuration
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TC- 446 Service Manual 2) The First Mixer The signal from RF amplifier is mixed with the first local oscillator signal from PLL frequency synthesizer in the first mixer (Q23) to generate a 21.4MHz first IF signal. The first IF signal is then fed through two monolithic crystal filters (XF1) to remove spurious signals from adjacent channels. 3)
IF Amplifier
The first IF signal is amplified in Q22 and then enters the IF process chip IC1. The signal is mixed with the second local oscillator signal in IC1 to create a 455KHz second IF signal. The second IF signal is then fed to a 455KHz ceramics filter (CF1) to eliminate unwanted signals before it is amplified and FM detected in IC1. 4) AF Amplifier The demodulated AF signal obtained from IC1 is amplified in IC7 (1/4), and then filtered by low pass filter Q19 and high pass filter Q20, and then de-emphasized by R130 and C156. The resulting AF signal passes through a volume control circuit and then is amplified to a sufficient level to drive the speaker by AF power amplifier (IC8). 5)
Squelch
Part of the AF signal from IC1 enters IC1 again, and the noise component is amplified and rectified by a filter and an amplifier to produce a DC voltage corresponding to the noise level. The DC signal from IC1 goes to the analog port of the microprocessor (IC11). IC11 determines whether to output sounds from the speaker by detecting whether the input voltage is higher or lower than preset value. To output sounds from the speaker, IC11 sends a high level signal to the MUTE and AFCO lines and turns IC8 on through Q12. FM IF IC1
IC7
IF AMP
DET
DET
HPF AMP
AF
LPF
HPF
SW
AF/PF AMP IC8 SP
Q12 SW
IC7 LPF
2
39 40
1 TI
AFCO
MUTE
BUSY
IC11 MCU
Figure 3.
AF amplifier and squelch circuit
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TC- 446 Service Manual 6) Receive signaling CTCSS/CDCSS Audio frequencies over 300Hz of the output signal from IC1 is cut off by a low-pass filter. The resulting signal enters the microprocessor IC11. IC11 determines whether the CTCSS/CDCSS matches the preset value and controls the MUTE and AFCO and the speaker sound output according to the squelch results. 3.
PLL Frequency Synthesizer PLL circuit generates the first local oscillator signal for reception and the RF signal for transmission. 1) PLL Circuit The step frequency of PLL circuit is 2.5KHz or 6.25 KHz. A12.8MHz reference oscillator signal is divided at IC2 by a fixed counter to produce a 2.5 KHz or 6.25 KHz reference frequency. Output signal from voltage control oscillator (VCO) passes through buffer amplifier Q14 and is divided at IC2 by the dual-module programmable counter. The divided signal is compared in the phase comparator IC2 with the 2.5 KHz or 6.25 KHz reference signal. The output signal from phase comparator is filtered through a low-pass filter and passed to the VCO to control the oscillator frequency. (See figure 4)
Figure 4 PLL circuit 2) VCO The operating frequency is generated by Q16 in transmit mode and by Q8 in receive mode. The operation frequency generates a voltage through the phase comparator to control the varactor diodes, so as to keep the oscillator frequency consistent with the preset frequency in CPU (D2 and D3 in transmit mode and D7 and D8 in receive mode). T/R pin is set high in receive mode causing Q6 to turn off Q16 and turn Q7 on. The T/R pin is set low in transmit mode. The output from Q8 and Q16 is amplified by Q14 and sent to the buffer amplifier.
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TC- 446 Service Manual 4.
Transmitter 1) Transmit audio The audio signal from microphone is amplified through IC3, and then pre-emphasized , and then filtered by another low-pass filter（separate filter）(Q25 and Q24) to eliminate the frequencies over 3KHz. The resulting signal enters the VCO for direct FM modulation. (See 2)
figure 5) CTCSS/CDCSS Encoder The necessary frequency for CTCSS/CDCSS encoder is generated by IC11 and FM-modulated to the PLL reference signal. Since the reference OSC does not modulate the loop characteristic frequency or higher, modulation is performed at the VCO side by splitter. (See figure 5)
Figure 5 transmit CTCSS 3)
RF amplifier The transmit signal obtained from VCO buffer amplifier Q14 is amplified by Q15 and Q17. This amplified signal is passed to power amplifier Q32 and Q31, and is capable of producing a 4.0W RF power.
4)
Antenna Switch and LPF The RF amplifier output signal is passed through a low-pass filter network and a transmit/receive switch circuit before it is passed to the antenna terminal. The transmit/receive switch circuit is comprised of D11 and D12. D11 and D12 is turned on in transmit mode and off in receive mode.
5. Power The 5V reference power supply for the control circuit is derived from an internal battery. The reference power provides a 5V supply in transmit mode [T_V], a 5V supply in receive mode [R_V], and a 5V supply shared in both modes based the control signal from the microprocessor. 6. Control System The IC11 CPU operates at 7.3728MHz.
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TC- 446 Service Manual
CPU Pins PIN No.
PIN NAME
I/O
DESCRIPTION
1
TI
I
CTCSS/CDCSS input
2
BUSY
I
Input busy signal
3
BATT
I
Detect battery voltage
4
TIBI
I
CTCSS/CDCSS exterior circuit central point input
5
NC
6
SAVE
O
Power saving control
7
TXLow
O
Transmitter power control
8
NC
9
DAT
O
data output
10
CLK
O
clock output
11
LE
O
PLL IC enable
12
BEEP
O
Beep output
13
SCL
O
E2PROM clock cable
14
SDA
I/O
E PROM data cable
15
MUTE
O
MIC mute control
16
MS1
I
Model set
17
GREEN
O
Green light control
H: light
18
RED
O
Red light control
H: light
19
TXD
O
RS-232C output
20
RXD
I
RS-233C input
21
PTTK
I
PTT key input
22
MS2
I
Standard model select
23
RXC
O
Receiver power control
24
NC
25
RESET
I
Reset input
26
SELF
I
Self-program
27
TXC
O
Transmitter power control
28
XIN
I
Oscillator input
29
XOUT
O
Oscillator output
30
Vss
I
Grounding
31
R/T
O
TX/RX control
H：RX
L： TX
32
UL
I
PLL unlock detector
H: Lock
L: unlock
33
IF-SELECT
I
IF select
34
MONIK
I
MONI key input
35
ENC0
I
Channel selector knob encode input
36
ENC1
I
37
ENC2
I
H: OFF
L: ON
H: Low power L: High power
2
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H: Mic mute
L: Mic enable
H: Non-standard L: Standard L: power on
L: on H:on
H: 21.4MHz
L: 45.05MHz
TC- 446 Service Manual
38
ENC3
I
39
AF MUTE
O
Audio muting control
40
AFP
O
Audio power control
41
TONE5
O
CTCSS code output
42
TONE4
O
CTCSS code output
43
TONE3
O
CTCSS code output
44
TONE2
O
CTCSS code output
45
TONE1
O
CTCSS code output
46
TONE0
O
CTCSS code output
47
WNTC
O
W/N L: Wide
H: Narrow
47-70
NC
71
Vcc
I
Power input: 5V
72
VREF
I
A-D converse reference voltage
73
Avss
I
A-D GND
74-77
NC
78
NC
79
NC
80
NC
－ 13 －
TC- 446 Service Manual
Part List 1 No.
P/N
Qty.
Ref. No.
Address
1
3001051830000
Chip resistor 0402 18KΩ J 1/1
Material Name
1
R622
B3I
2
3001060000000
Chip resistor 0603 0Ω J 1/10W
16
C23
B3F
D20
T1D
4
L3
B3H
5
Q41
T3F
6
R106
T3F
7
R107
B3B
8
R108
B3E
9
R110
T4G
10
R151
B5E
11
R192
B4E
12
R194
B3F
13
R197
B4F
14
R202
B2B
15
R508
B5B
16
R601
B1E
R602
B3C
R112
T3E
3
17 18
3001061000000
Chip resistor 0603 10Ω J 1/10
6
19
R113
T5J
20
R164
B2C
21
R196
B4G
22
R80
B2D
23
R82
B4G
R127
B5F
25
R147
B4E
26
R74
B2C
27
R75
B4J
28
R76
B5E
29
R90
T5H
24
30
3001061010000
3001061020010
Chip resistor 0603 100Ω J 1/1
6
R203
T2E
31
Chip resistor 0603 1KΩ J 1/10
12
R39
B3B
32
R51
B1F
33
R52
T3F
34
R53
B2D
35
R56
B2B
36
R57
B5B
37
R58
T4B
38
R59
T3B
39
R60
T2D
40
R61
T2D
41
R89
T4I
R100
T4B
43
R204
T2G
44
R36
B4B
42
3001061030010
Chip resistor 0603 10KΩ J 1/1
10
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TC- 446 Service Manual
Part List 1 No.
Ref. No.
Address
45
R37
T2E
46
R38
B2A
47
R40
B3F
48
R41
T5F
49
R42
T5E
50
R44
B2I
51
R45
B2I
52
P/N
R10
B4C
R12
B4B
54
R13
B3D
55
R15
B3D
56
R175
T2B
57
R176
T2B
58
R18
T2C
59
R35
T2C
60
R623
B4E
61
R624
B4F
62
R625
B3E
63
R626
B3F
64
R7
B4B
65
R8
B2E
66
R9
B1D
R109
T2B
3001061050010
Chip resistor 0603 100KΩ J 1/
Qty.
53
67
3001061040010
Material Name
15
Chip resistor 0603 1MΩ J 1/10
2
68 69
3001061230000
Chip resistor 0603 12KΩ J 1/1
2
3001061240010
Chip resistor 0603 120KΩ J 1/
3
70 71
R116
T3B
R170
B1D
R617
B4H
R11
B3B
72
R124
T3F
73
R72
B2D
74
3001061510000
Chip resistor 0603 150Ω J 1/1
2
75 76
3001061520000
Chip resistor 0603 1.5KΩ J 1/
3
77 78
R68
B2E
R69
B2C
R48
B3E
R50
T5F
R55
T2E
R161
T4F
80
R162
T4G
81
R163
T4F
79
82
3001061530010
3
R139
B4B
83
R14
B3D
84
R140
B4A
85
R141
B4A
86
R142
B4A
87
3001061540000
Chip resistor 0603 15KΩ J 1/1
3001061820000
Chip resistor 0603 150KΩ J 1/
5
Chip resistor 0603 1.8KΩ J 1/
2
88
－ 15 －
R131
T4E
R144
B3C
TC- 446 Service Manual
Part List 1 No.
P/N
Qty.
Ref. No.
Address
89
3001061850000
Chip resistor 0603 1.8MΩ J 1/
Material Name
2
R155
T5G
R156
T5F
91
3001062030000
Chip resistor 0603 20KΩ J 1/1
1
R98
B3D
92
3001062220000
Chip resistor 0603 2.2KΩ J 1/
4
90
R165
B4F
93
R174
T4H
94
R3
B4B
95
R6
T2B
R104
B3H
R120
T4G
R145
T5F
R167
T1D T3E
96
3001062230000
Chip resistor 0603 22KΩ J 1/1
2
97 98
3001062240010
Chip resistor 0603 220KΩ J 1/
2
99 100
3001062710000
Chip resistor 0603 270Ω J 1/1
1
R616
101
3001062720000
Chip resistor 0603 2.7KΩ J 1/
4
R114
B1B
102
R49
B4D
103
R64
B2G
104
R65
B2G
R102
B3H
R132
B3C
R16
B3D
R2
B3C
105
3001062730010
Chip resistor 0603 27KΩ J 1/1
2
106 107
3001062740010
Chip resistor 0603 270KΩ J 1/
2
108 109
3001063020000
Chip resistor 0603 3KΩ J 1/10
1
R81
B3F
110
3001063310010
Chip resistor 0603 330Ω J 1/1
5
R122
B3G
111
R146
B4D
112
R5
B4E
113
R67
B2D
114
R96
B2B
R135
B4B
116
R136
B4A
117
R137
B4B
118
R138
B5A
119
R25
B4B
120
R26
B4D
121
R27
B2F
122
R28
B1F
123
R29
B2D
124
R30
B2E
125
R31
B3G
126
R32
B5E
127
R33
T5F
128
R34
B2D
115
3001063320000
Chip resistor 0603 3.3KΩ J 1/
14
129
3001063330010
Chip resistor 0603 33KΩ J 1/1
1
R24
T2G
130
3001063340000
Chip resistor 0603 330KΩ J 1/
1
R43
T2A
131
3001063930010
Chip resistor 0603 39KΩ J 1/1
5
R152
T5F
R153
T5F
132
－ 16 －
TC- 446 Service Manual
Part List 1 No.
Ref. No.
Address
133
R154
T4F
134
R158
T5F
135
R159
T5E
136
P/N
R115
B2A
R123
B3G
138
R125
B3H
139
R191
B2B
4
L1
B4B
141
R118
B2I
142
R166
B4F
143
R62
B2I
R121
T1B
144
3001064710000
Chip resistor 0603 47Ω J 1/10
Qty.
137
140
3001064700000
Material Name
3001064720000
Chip resistor 0603 470Ω J 1/1
4
Chip resistor 0603 4.7KΩ J 1/
6
145
R177
T2A
146
R84
B2C
147
R87
T2A
148
R88
T1C
149
R99
T1B
R101
B4H
151
R103
B4G
152
R105
B1E
153
R128
B3B
154
R4
T2B
155
R54
T3G
156
R606
T3I
157
R607
T3I
158
R608
T3I
159
R609
T3I
160
R610
T2C
161
R615
B3B
150
3001064730000
Chip resistor 0603 47KΩ J 1/1
13
162
R93
T2F
3001064740010
Chip resistor 0603 470KΩ J 1/
2
R22
T1D
R94
T3F
3001065620010
Chip resistor 0603 5.6KΩ J 1/
2
R130
B4B
R79
B2D
3001065630000
Chip resistor 0603 56KΩ J 1/1
4
R149
B3E
168
R157
T4F
169
R198
T4E
163 164 165 166 167
170
R627
171
3001065640000
Chip resistor 0603 560KΩ J 1/
1
R148
B4D
172
3001066810010
Chip resistor 0603 680Ω J 1/1
1
R70
B3F
173
3001066820000
Chip resistor 0603 6.8KΩ J 1/
1
R85
T4F
174
3001066830000
Chip resistor 0603 68KΩ J 1/1
1
R618
175
3001066840000
Chip resistor 0603 680KΩ J 1/
1
R134
B3C
176
3001067540000
Chip resistor 0603 750KΩ J 1/
1
R160
T4G
－ 17 －
TC- 446 Service Manual
Part List 1 No.
P/N
Qty.
Ref. No.
Address
177
3001068200000
Chip resistor 0603 82Ω J 1/10
Material Name
1
R171
B1D
178
3001068210010
Chip resistor 0603 820Ω J 1/1
3
179 180
R47
B4D
R619
B4D
R66
B1F
R117
B2B
182
R169
B1D
183
R628
T2E
181
184
3001068220000
3001068230010
Chip resistor 0603 8.2KΩ J 1/
3
Chip resistor 0603 82KΩ J 1/1
2
185
R133
T2C
R97
B3C
186
3001068240000
Chip resistor 0603 820KΩ J 1/
1
R1
B4B
187
3001080000000
Chip resistor 1206 0Ω J 1/4W(
4
F1
T4G
188
R172
T2H
189
R173
T2I
190
R77
T2H
191
3002994730000
Trimmer resistor 2.7*2.0*1.6 47K
1
VR2
T5E
192
3002996830000
Trimmer resistor(2*2) 68KΩ(+25%)
3
VR3
T4E
193
VR4
T1B
194
VR5
195
3005991030070
Array resistor 0603 10KΩ*4 J 1/
2
196
CP1
T1B
CP6
T4A
197
3005061030040
Array resistor 0603 10KΩ*2 J 1/
1
CP5
T1B
198
3005064720000
Array resistor 0603 4.7KΩ*2 J 1
1
CP4
T1B
199
3005064720010
Array resistor 0603 4.7KΩ*4 J 1
1
CP3
T1B
200
3101050100000
Chip capacitor 0402 1PF C 50V
4
C104
B4G
201
C143
B4I
202
C146
B4I
203
C95
B1E
C134
B5H
C195
B2B
204
3101050200010
Chip capacitor 0402 2PF B 50V
2
205 206
3101050300000
Chip capacitor 0402 3PF B 50V
3
207 208
C103
B2B
C105
B4G
C136
B3H
209
3101050400010
Chip capacitor 0402 4PF B 50V
1
C186
B2C
210
3101050500010
Chip capacitor 0402 5PF B 50V
3
C107
B4E
C108
B5E
C189
B2C
C163
B4F
214
C164
B4G
215
C91
B2D
216
C94
B4E
211 212 213
217
3101050590020
3101050600010
Chip capacitor 0402 0.5PF B 50
Chip capacitor 0402 6PF B 50V
4
C106
B5E
218
5
C182
B1D
219
C96
B2D
220
C97
B2E
－ 18 －
TC- 446 Service Manual
Part List 1 No.
P/N
Material Name
Qty.
221 222
6
B3G
C101
B4I
C139
B4I
224
C141
B4J
225
C142
B4I
226
C193
B1D
227
C90
B1E
3101051000000
Chip capacitor 0402 8PF B 50V
Address
C98
223
228
3101050800000
Ref. No.
C135
B3F
229
Chip capacitor 0402 10PF D 50V
6
C144
T4F
230
C187
B2C
231
C253
232
C255
233
C88
B2E
C132
B2D
235
C15
B2A
236
C16
B2A
234
3101051010030
Chip capacitor 0402 100PF J 50
6
237
C17
B2A
238
C179
B3C
239
C180
B2A
C109
B2C
241
C110
B2C
242
C111
B4H
243
C113
B2B
244
C114
B3H
245
C121
B2E
246
C147
B4I
247
C252
248
C26
B2B
249
C59
B1G
250
C60
B1G
251
C61
B2G
252
C62
B2G
253
C65
B1C
254
C66
T1E
255
C68
B3H
256
C69
B3C
257
C70
B4A
258
C71
B5B
259
C73
B3E
260
C74
B4E
261
C75
T4F
262
C76
T4G
263
C77
T4G
264
C78
T2D
240
3101051020010
Chip capacitor 0402 1000PF K 5
－ 19 －
30
TC- 446 Service Manual
Part List 1 No.
Ref. No.
Address
265
C79
T1E
266
C80
T1D
267
C81
T1C
268
C82
B2I
269
C83
B2I
C10
T5F
C11
T1B
272
C12
B3I
273
C137
T2I
274
C2
B4B
275
C240
T3J
276
C241
T3J
277
C242
T3J
278
C243
T3J
279
C3
B4B
280
C4
B4C
281
C5
B1F
282
C7
B2C
283
C8
B4A
284
C9
T5F
270
P/N
3101051030020
Material Name
Chip capacitor 0402 0.01UF K 2
Qty.
15
271
285
C178
T2B
286
C233
B4E
287
C246
B3B
288
C250
T3E
289
C37
B4B
290
C38
B4C
291
C39
B4D
292
C40
T2F
293
C43
B3C
294
C45
B5B
295
C46
B3C
296
C50
T4G
297
C51
B3I
298
C64
T2F
299
C84
T2E
300
3101051040040
3101051590000
Chip capacitor 0402 0.1UF K 10
Chip capacitor 0402 1.5PF B 50
15
2
301
C140
B4I
C196
B3E B5B
302
3101051810000
Chip capacitor 0402 180PF J 50
1
C18
303
3101051830000
Chip capacitor 0402 0.018UF K
1
C156
B5B
304
3101052200010
Chip capacitor 0402 22PF J 50V
2
C100
B2D
C188
B1C
3101052210010
Chip capacitor 0402 220PF J 50
3
C13
B4B
307
C14
B4B
308
C239
T5I
305 306
－ 20 －
TC- 446 Service Manual
Part List 1 No.
P/N
Qty.
Ref. No.
309
3101052220000
Chip capacitor 0402 2200PF K 5
Material Name
1
C254
310
3101052230000
Chip capacitor 0402 0.022UF K
4
Address
C167
T5F
311
C168
T4G
312
C169
T4G
313
C44
B4B
314
3101052240010
Chip capacitor 0402 0.22UF Z 1
1
C123
B1B
315
3101052490010
Chip capacitor 0402 2.4PF B 50
2
C102
B4I
C192
B1D
317
3101052710000
Chip capacitor 0402 270PF J 50
1
C67
B3H
318
3101052720000
Chip capacitor 0402 2700PF K 5
1
C172
T5F
319
3101053300000
Chip capacitor 0402 33PF J 50V
5
C175
T2B
320
C176
T3B
321
C52
B4B
322
C53
B4B
316
323
C54
B4C
324
3101053320010
Chip capacitor 0402 3300PF K 5
1
C166
T5F
325
3101053330000
Chip capacitor 0402 0.033UF K
5
C150
B4B
326
C151
B4B
327
C152
B4B
328
C153
B4B
C160
B3D
C126
B1B
329 330
3101053340000
Chip capacitor 0402 0.33UF K 6
2
C133
B4G
332
3101053900000
Chip capacitor 0402 39PF J 50V
1
C138
B3H
333
3101053920000
Chip capacitor 0402 3900PF K 2
1
C181
T2C
334
3101053930000
Chip capacitor 0402 0.039UF K
1
C122
T2E
335
3101054700010
Chip capacitor 0402 47PF J 50V
1
C55
B3I
336
3101054710010
Chip capacitor 0402 470PF K 50
22
C149
B2G
C197
B3B
338
C20
B4B
339
C204
B3F
340
C207
B3F
341
C208
B4J
342
C21
B2E
343
C22
B2D
344
C231
B1C
345
C24
B4G
346
C25
B2B
347
C251
B3E
348
C27
B3G
349
C28
B4H
350
C29
B3I
351
C30
B4I
352
C31
B2D
331
337
－ 21 －
TC- 446 Service Manual
Part List 1 No.
Ref. No.
Address
353
C32
B5E
354
C33
B5F
355
C35
B4F
356
C36
B4E
357
C42
B4G
358
P/N
3101054720000
Material Name
Chip capacitor 0402 4700PF K 5
Qty.
2
359 360
5
B4D
C157
T5F
C158
T4E
362
C161
T2C
363
C162
B3C
364
C237
T3E
3101055610000
Chip capacitor 0402 0.047UF K
T4F
C57
361
365
3101054730000
C232
Chip capacitor 0402 560PF K 50
2
366
C171
T5F
C34
T5G
367
3101055620000
【switch to 3101055620010】SMT
1
C47
B3D
368
3101057590000
Chip capacitor 0402 7.5PF(±0.1
1
C89
B4I
369
3101058200000
Chip capacitor 0402 82PF J 50V
1
C58
B4C
370
3101060100010
Chip capacitor 0603 1PF B 50V
1
C92
B2C
371
3101060200010
Chip capacitor 0603 2PF B 50V
1
C93
B4E
372
3101060600010
Chip capacitor 0603 6PF B 50V
1
C145
B4J
373
3101061020000
Chip capacitor 0603 1000PF K 5
4
C198
T4G
374
C235
B4J
375
C63
B1D
376
C72
B3D
C194
T4H
378
C48
T4G
379
C49
T4G
377
3101061040010
Chip capacitor 0603 0.1UF K 16
4
380 381
3101061800000
Chip capacitor 0603 18PF J 50V
2
3101064710000
Chip capacitor 0603 470PF K 50
2
3102992000040
Trimmer capacitor 3.2*2.5*1.25mm
5
382 383 384
R200
B2B
C19
B5H
C506
B3I
R111
B4E
R150
B5F
TC1
B1D
386
TC2
B1C
387
TC3
B4G
388
TC4
B5F
389
TC5
B4E
385
390
C124
B1B
391
3104071050020
Ta-capacitor 0805 1UF M 6.3V
6
C200
T4E
392
C202
B3B
393
C85
B1G
394
C86
B1F
C87
B2G
C174
T3F
395 396
3104081050000
Ta-capacitor 1206 1UF M 16V T
－ 22 －
1
TC- 446 Service Manual
Part List 1 No.
P/N
Qty.
Ref. No.
Address
397
3104081550000
Ta-capacitor 1206 1.5UF±20% 1
Material Name
1
C112
T2G
398
3104081560030
Ta-capacitor 1206 15UF M 6.3V
2
C115
B2C
C177
T1D
399 400
3104082250030
Ta-capacitor 1206 2.2UF K 16V
1
C165
T5F
401
3104082260040
Ta-capacitor 1206 22UF M 10V
3
C118
T2E
402
C247
T3E
403
C248
T3E
C117
B1B
C173
T4F
404
3104084750030
Ta-capacitor 1206 4.7UF K 16V
2
405 406
3104201070000
Ta-capacitor 2220 100UF M 6.3
1
C203
T5G
407
3104204760020
Ta-capacitor C-packing 47UF M 16V T
1
C120
B2G
408
3210107221000
Framework inductor 0805 220nH LQW2
1
L4
B4J
409
3210108230010
Framework inductor 1206 23nH LQW31
2
L16
B2B
L44
B1E
410 411
3210209102010
Framework inductor 1210 1uH LQH32M
1
L43
B5J
412
3210305150010
Multi-layer inductor 0402 15nH LQG15
1
L21
B3G
413
3210305180000
Multi-layer inductor 0402 18nH LQG15
1
L26
B2B
414
3210305220000
Multi-layer inductor 0402 22nH LQG15
3
L18
B2D
415
L19
B2D
416
L25
B3E
417
L17
B1C
418
L40
B5E
419
L47
B2C
420
L48
B1C
L39
B5E
421
3212105101000
Multi-layer inductor 0402 100nH HK10
4
3212105470000
Multi-layer inductor 0402 47nH HK100
2
L45
B2D
423
3212106339000
Multi-layer inductor 0603 3.3nH HK16
1
L29
B3H
424
3213212102000
Multi-layer inductor 1008 1uH NLV25T
1
L50
425
3213212331000
Multi-layer inductor 1008 330nH NLV2
1
L49
B3E
426
3213306102000
Multi-layer inductor 0603 1uH MLF160
1
L14
T4H
427
3213306221010
Multi-layer inductor 0603 0.22uH MLF
1
L41
T2E
428
3213306332000
Multi-layer inductor 0603 3.3uH MLF1
2
L46
B2C
L5
B2E
422
429 430
L12
B3G
431
3221506601000
Chip ferrite bead 0603 600Ω±2
5
L13
B2B
432
L6
B2D
433
L7
B2D
434
L8
B2A
435
3221507221000
Chip ferrite bead 0805 220Ω±2
1
L11
B3H
436
3221507600000
Chip ferrite bead 0805 60Ω±25
2
L10
B3J
L15
B2G
438
3231321050000
Air-core inductor E2 0.32*1.0*5TR
1
L2
B3H
439
3231351630000
Air-core inductor E2-0.35*1.6*3TR
9
L22
B4H
L23
B4I
437
440
－ 23 －
TC- 446 Service Manual
Part List 1 No.
Ref. No.
Address
441
L24
B4I
442
L28
B4J
443
L33
B4G
444
L34
B5E
445
L35
B4E
446
L36
B4E
447
L38
B5F
448
P/N
3231351640000
Material Name
Air-core inductor E2-0.35*1.6*4TL
Qty.
2
449
L31
B4F
L32
B4G
450
3231351680000
Air-core inductor E2-0.35*1.6*8TR
1
L30
B3I
451
3303010500290
Switch diode 1SS372(TE85L.F
1
D18
T4F
452
3303020100020
Switch diode MA2S11100L SS-
2
D25 D9
B2C
454
3303020100070
Switch diode MA2Z07700L SOD
1
D11
B4I
455
3303020100080
Switch diode MA2S07700L 1.7
3
D12
B5H
D5
B3F
453
456 457
D6
B3F
458
3303030100010
Switch diode DAN222(TL) SOT
1
D19
T4G
459
3303210200000
Switch diode MA2S37600L SS-
4
D2
B2E
460
D3
B2D
461
D7
B1C
462
D8
B1C T3J
463
3307110100080
LED KPT-1608SGC ultra-high
1
D22
464
3307110100070
LED KPT-1608SRC ultra-high
1
D24
T3J
465
3399990000160
Varactor MA2Z36000L 30V
1
D4
B1D
466
3399990000220
Diode UDZ3.0B SOD-323
1
D10
B2B
467
3401001000080
Transistor 2SA1362-ER（TE85.
1
Q40
T3F
468
3401002000990
Transistor 2SC5108-Y(TE85L.
3
Q13
B2B
Q14
B2D
469 470
Q22
B4D
471
3403007000000
Transistor DTA114EE(TL) PNP
1
Q10
B4D
472
3403007000020
Transistor DTA114YE(TL) PNP
2
Q34
T2B
Q9
T2B
Q28
B2J
Q30
B2J
Q35
T2B
Q12
T2F
Q39
T2F
Q1
B1F
Q2
B2F
473 474
3403008000010
Transistor DTC114EE(TL) NPN
3
475 476 477
3403008000070
Transistor DTC144EE(TL) NPN
2
3403009000010
Transistor UMG3N(N-TR) NPN
2
478 479 480 481
3404002000000
Transistor PRF957 NPN PHILI
1
Q16
B1D
482
3406001000090
Transistor 2SC4988FRTR-E NP
1
Q17
B3G
483
3408002000030
Transistor 2SC4226-R24-A NP
1
Q15
B2D
484
3411002000020
Transistor 2SC5343EG NPN AU
6
Q18
B2D
－ 24 －
TC- 446 Service Manual
Part List 1 No.
Ref. No.
Address
485
P/N
Material Name
Qty.
Q19
B4A
486
Q20
B4A
487
Q24
T5F
488
Q25
T5F
489
Q26
T4G
490
3499000000140
Transistor 2SK508-K52-T1B-A
1
Q8
B2C
491
3499000000150
Transistor UMC4(NTR) NPN/PN
1
Q7
B1D
492
3499000000180
Transistor UFMMT717 PNP SOT
2
Q4
B1F
Q5
B1F
Q23
B3E
493 494
3501020000030
FET 3SK318YB-TL-E-Q
2
495
Q27
B5E
496
3503010000010
FET 2SJ243-T1-A P-c
1
Q6
B1C
497
3503020000010
FET 2SK1588-T1-AZ N
1
Q41
T3F
498
3503020000030
FET 2SK1824-T1-A N-
3
Q21
B5B
499
Q46
B2E
500
Q50
B4I
501
3503040000000
FET UPA572T-A N-cha
1
Q3
B2G
502
3504990000010
FET RD01MUS2-T113 P
1
Q32
B3G
503
3504990000020
FET RD07MVS1-T112 P
1
Q31
B3I
504
3602028004610
AF amplification IC KIA6278F-EL/P
1
IC8
T3E
505
3603002005440
IF processing IC TA31136FNG(EL
1
IC1
B4C
506
3603008005040
Operational amplifier NJM2902V 4 OA J
1
IC7
B3C
507
3604002055090
PLL TB31202FN-EL(ELP
1
IC2
B2A
508
3605008005010
Operational amplifier NJM2100V 2 OA J
1
IC3
T4F
509
3608015000000
Power managing IC (voltage regulator) XC6201P5
1
IC4
T1D
510
3609004005280
Reset IC PST9140NR MITSU
1
IC9
T2A
511
3610045000040
SCM M38223M4A-137HP#
1
IC11
T3C
512
3612031004400
Memory AT24C08AN-10SU-2
1
IC5
T5B
513
3701012850010
TCXO 12.8MHz NSA0
1
X2
514
3701737230020
Crystal 7.3728MHz DSX530G
1
X3
T3B
515
4100500101600
TC-500US(U) PCB FR4
1
516
3104081060080
Ta-capacitor 1206 10UF M 10V
4
C1
B4B
517
C125
B4F
518
C155
B4A
519
C159
B3B
－ 25 －
TC- 446 Service Manual
Adjustment Description The radio can be adjusted with PC programming software or by manual adjustment. Manual adjustment procedure of TC-446 is as follow. (Refer to “model set mode”and “manual adjust mode”in the section Software Specification.) Instrument: Radio Communication Test Set
1 set
Scanner 3A/10V Power Supply
1 set 1 set
Digital Voltmeter
1 set
3A Ammeter
1 set
Adjustment: 1. Initializing: It’ s necessary to set the model and initialize the radio before alignment because there is no needed information in EEPROM when the radio is manufactured. Please refer to the “model set mode”in the section Software Specification for details. 2. Adjustment: Some items can be adjusted in conventional communication mode and the others in manual adjust mode. Turn on the power, the radio enters conventional communication mode. If manual adjust mode is enabled, turn on the power while holding down PTT and MONI simultaneously, the radio enters manual adjust mode after 2 seconds. (Refer to the section Software Specification.)
VCO Measurement Item
Adjustment
Test Instrument
Terminal
Part
Method
1.Power supply 1.power voltage DC 6V 1.TX High. Turn to CH15 in manual adjust mode and press 2.Transmit VCO
2V±0.1V V
PTT. TC1
lock voltage 2.TX Low. Turn to CH14 in manual adjust mode and press PTT.
Digital Voltmeter
CV
2V±0.1V
1.RX High. Turn to CH15 in 3. Receive
manual adjust mode.
2V±0.1V
VCO lock voltage
Specification
Condition
TC2 2.RX Low. Turn to CH14 in
2V±0.1V
manual adjust mode.
－ 26 －
/Remarks
TC- 446 Service Manual RECEIVER: (Enter the manual adjust mode) Measurement
Adjustment Specification
Item
Condition
Test Terminal
Part
/Remarks
Method
Instrument
Adjust the waveform to the top, and the top is flat, the 1.RX Center. Turn to
TC3
bandwidth is about 100kHz,
TC4
the sign of RX central
TC5
frequency is at the middle
4. Band Pass CH13 in manual adjust Filter
Scanner
ANT . TP2
mode.
of the waveform.
1.RX Center. Turn to CH13 in manual adjust mode (long press MONI key to switch N/W).
Radio Communicati on Test Set
2. RX Low. Turn to CH14 in manual adjust 5.sensitivity
mode (long press MONI key to switch N/W).
-118dBm ANT MOD:1KHz Speaker ±1.5kHz
higher
Jack
(Narrow)
3.RX High. Turn to CH15 in manual adjust
SINAD: 12dB or Check
FILER: 0.3-3.4kHz
mode (long press MONI key to switch N/W). Radio 1.RX Center. Turn to
Communic-
CH2 in manual adjust
ation Test
Level 9
Adjust squelch
Adjust to just close the mode. Adjust by
Set
level 9 squelch.
pressing PTT or MONI. SSG output: -117dBm 6.Squelch
ANT Speaker
Radio 2.RX Center. Turn to
Communic-
CH3 in manual adjust
ation Test
Jack Level
3 Adjust squelch
Adjust to just close the mode. Adjust by
Set
level 3 squelch.
pressing PTT or MONI. SSG output: -125dBm
－ 27 －
TC- 446 Service Manual Transmitter Measurement
Adjustment Specification
Item
Condition
Test Terminal Parts
Method
/Remarks
equipment
7.Transmit frequency
8.Max. Deviation
1. TX Center. Turn to CH13 in manual adjust mode and press PTT.
Radio Communication Test Set
1. Turn to CH13 in manual
Radio Communication
adjust mode and press PTT
Test Set
(long press MONI key to switch
LPF:
N/W).
AF:1kHz 120mV
ANT
ANT
15kHz MIC Jack
TC6
Adjust
it
center
Error ≤±250Hz
frequency
Adjust VR2
to
deviation
to:
2.0kHz±200Hz (narrow)
Radio Communication 1. Turn to CH13 in manual 9. Modulation adjust mode and press PTT Sensitivity
Test Set FILTER:
ANT
(long press MONI key to switch
FILER:
MIC Jack
N/W).
0.3-3.4kHz
Check deviation:
1.5±0.15 kHz(narrow)
AF:1kHz 12±2mV 1. CTCSS: 67.0Hz. Turn to CH4 in manual adjust mode. 10. CTCSS Balance
67.0Hz Adjust
Radio Communication Test Set
2. CTCSS: 250.3Hz. Turn to
HPF: 20Hz
CH16 in manual adjust mode
LPF:300Hz
VR3,
deviation
ANT
VR3
condition
2
are
consistent, the difference
250.3Hz
≤200Hz
CTCSS
and press PTT. 1. TX Center. Turn to CH4 11. CTCSS Deviation
12. CDCSS Deviation
Adjust deviation to:
(wide) and CH4 (narrow) in manual adjust mode. Adjust by pressing PTT or MONI.
CTCSS
tested on condition 1 and
0.4kHz±100Hz(Narrow) Radio Communication Test Set
1. Turn to CH5 (wide) and CH7
HPF: 20Hz
(narrow) in manual adjust mode.
LPF:300Hz
ANT Adjust deviation to:
0.4kHz100Hz(Narrow)
Adjust by pressing PTT or MONI.
13. low
power voltage DC 6V
Power
Radio Communication Test Set
500±200mW
ANT
1. Turn to CH1 in manual adjust 14. mode. Adjust the power supply Low Battery
voltage at 5.3V. Adjust by
Adjust the level to make Digital Voltmeter
LED just flash.
Alert Level pressing PTT or MONI. Note: In manual adjust mode, when channel selector knob is positioned at channel 1-channel16, MIC jack can’ t connect with external cables. After adjustment is completed, short out the two SELF points and then turn the power on, the radio enters model set mode . Then press PTT to disable the manual adjust mode.
－ 28 －
TC- 446 Service Manual
TC500 Series Troubleshooting Chart I. Receiver: 1. No receive or low RX sensitivity / intermittent RX output: Start Check CF1(455K2nd IF Inject 21.4MHz signal into Q22 pin C; SSG output ≤ -92dbm; Audio heard from SPK?
filter), IC1(IF IC), nd
X1(20.945M 2
N
LO), CD1(demodulator);
Y
st
Check XF1 (1 IF filter), Q22; Replace faulty components.
Inject 21.4MHz signal into XF1 IN; SSG output≤ -103dbm ; Audio heard from SPK?
N
-
Y
N
Power supply at Q9(5R) OK?
Y Check Q23 (mixer), Q27, Tc5; Replace faulty
Inject 1KHz RX signal into Q27(RF AMP)IN; SSG≤-113dbm; Audio heard from SPK?
N Check if no-solder joint at IC11 pin 23; Check Q9; Replace faulty components.
Y
Inject 1KHz RX signal into antenna (wide: SSG≤ -118dbm,narrow: SSG≤-116dbm); Audio heard from
N Adjust TC3, TC4, TC5; Check TC3, TC4, TC5, C94, C93, C106, C163, C164, N C105; Replace faulty components.
－ 29 －
TC- 446 Service Manual
Repair Example：(Tested by communication test set after power on) 1) Symptom: TX OK; no RX at all, but RX frequency OK; no-solder at one end of crystal X1; Cure: touch up X1 2) Symptom: TX OK; low RX sensitivity or intermittent RX output; Cure: replace 455KHz filter 3) Symptom: TX OK; low RX sensitivity, but sensitivity OK after injecting 45.05MHz signal into XF1; Cure: adjust TC3, TC4, and TC5 in turn 2、No RX audio output（no audio from SPK, sound abnormal） ： Symptom 1: no audio after power on/no or low audio in monitor mode： （activate power-on alert tone and monitor features）
－ 30 －
TC- 446 Service Manual Start
Turn to max. VOL; Hold down MONI; around 2.8V (limit) audio output at SPK plug?
Check SPK plug, SPK, spring; Replace faulty components;
1 KHz audio input at IC8(AF AMP) pin1?
N Check VR1 and its wiring to IC8; Replace faulty components.
N
Y
Hold down MONI; 6V voltage at IC8 pin8?
N
Y
Hold down MONI; 5V output at IC11 pin40 (AVP)?
Audio output at IC8 pin 7?
Y
N Check IC8 and peripheral
N
Q41 conductive?
Y
Y
See control Check if Q39 and Q12 conductive; Replace faulty components.
troubleshooting
Replace
faulty components.
N section
components;
Check C203, c239; Replace faulty components.
N Check R203, R37, C84, C66;
－ 31 －
TC- 446 Service Manual
Symptom 2: audio OK after power on, no RX audio output or audio distortion in RX (abnormal noise output while holding down MONI) Start
Hold down MONI; Audio output at IC7 pin1?
Check if Q21 conductive; Check operating status of Q19, Q20; Check C44, C150, C151, C152, C153, C45; Replace faulty components.
Y
N Y Hold down MONI; Audio output at IC7 pin3?
5V voltage at IC7 pin4?
Y
N
N
Y
Check IC1, CD1 (C24 demodulation), peripheral components; Replace faulty components.
5V voltage at IC1(IF) pin4?
Check IC7, IC11, peripheral components; Replace faulty components.
N
Check the wiring between IC1 pin4 and Q9;
Check the components between Q9 and IC11 pin 23. Replace faulty components.
Repair Example: 1) Symptom: Hold down MONI, MONI LED glows but no noise output (no RX audio), SPK resistance OK; 6V measured at Q40 IN, but no 6V output while holding down MONI; Cure: replace Q40（2SA1362） 2) Symptom: Hold down MONI, 6.0V voltage at IC8 pin8 but no audio output at pin7; Cure: replace IC8
－ 32 －
TC- 446 Service Manual II. Transmitter： 1、No power (low output power) Start
Plug into standard power supply (7.5V); Connect instruments; Toggle on TX; Observe current&power changes.
Low current and no power output in TX
High current but no or low power output in TX
In TX, 6.0V source voltage at Q31?
Y In TX, 1.8~2.5 V gate voltage at Q31?
Check Q32, Q17, Q38, peripheral components; Replace faulty components.
In TX, around 1.1W power at D11 positive end?
Y 1.1W In TX, around power at D11 negative end?
Check L3, Q31, C55;
N
Check Y C30, C139, C142, C141, C145; Replace faulty components.
Y Replace Q31;
Check D11, R75, C208, L4 N
In TX, 7.5V source voltage and 1.8~2.5V gate voltage at Q32?
. N Y － 33 －
Check bias circuit;
TC- 446 Service Manual N
L29, C138, C67 OK?
.
Replace faulty components;
Y
In TX, 4.8V collector voltage, 1.2V base voltage and 0.3V emitter voltage at Q17?
Check bias resistor and TX 5V power supply circuit.
N
Y N
R122, C98, R196,
Replace faulty
C42 R195 OK?
components;
Y C207 Y OK?
N
Replace faulty components;
Y C23 parameters and D5否 positive bias OK ?
Replace faulty
N
components; Check
Y
bias circuit.
Y
Check R80,
4V collector voltage, 1.8V base voltage and 1V emitter voltage at Q15?
N
R29, R79,
Y C97 arameters OK ? Y See
N VCO
Troubleshootin
Replace with components of the same spec;
－ 34 －
L18, R34,
TC- 446 Service Manual Repair Example： 1) Symptom: no TX power; > 3A TX current; Cure: replace Q31 2) Symptom: low TX power; Voltage at Q4, Q31, Q32 OK; 10mw power at Q31 （RD07）IN; Around 1W power at D11; Cure: replace Q31 2、No or low TX audio (test port for communication test set：AF OUT/AF IN) Start
Inject 1KHz/100mv AF signal into MIC plug; ± 4.2KHz ± 150Hz modulation deviation?
N
Check MIC plug and MIC; Replace faulty components;
Y N
Waveform input at IC3(NJM2100V) pin2 OK?
Check L14, C48, C169, C168; Replace faulty components.
Y
In TX, amplified 是 at waveform output IC3 pin7?
In
N
TX,
5V
voltage at IC3 pin 8?
Y In TX, waveform output at VR2?
Y
N
Check components between
Check Q24, Q25, VR2
VR2 and VCO (e.g.L10, R22,
(47K) and peripheral
C40); replace faulty
components;
components;
－ 35 －
N
Check IC3 and
Check
peripheral
connection
components;
Q4
C pin.
the to
TC- 446 Service Manual
Repair Example： 1)
Symptom: no TX audio, cracked VR2; Cure: replace VR2 and adjust
2) Symptom: low TX audio; poor modulation sensitivity of MIC after adjusting VR2 Cure: replace MIC II. PLL： 1、 TX or RX unlock：(Caused by faulty oscillator loop)
－ 36 －
TC- 446 Service Manual Start
Correct software mode settings and freq range?
Adjust to freq band/freq
N
set in the radio;
TX unlock: TX unlock on
RX unlock: RX unlock on
some channels?
some channels?
Y
N
Adjust TC1
Y
N
Adjust TC2
Voltage at RX CV?
Voltage at TX CV?
N
Y RX CV: > 4V or < 0.2V?
No TX CV
Y
Y
Y
Bias (pin C 4V) at Q8 OK?
sector; Bias (pin C 4V) at Q16 OK?
N
Check synthesized sector;
TX CV: > 4V or < 0.8V?
Check synthesized Y
No RX CV
N
Y
Y
4.1V output voltage at Q7?
Y
Y Adjust TC2; reliable solder & correct parameters of C186, C187, L46, R69, L16, C19, C188, L48, D8, D7, L17?
Adjust TC1; reliable solder & correct parameters of C182, C193, C95, L44, C192, C90, L5,D4?
Y
Reliable solder and correct parameters of R164, R9, L47, Q8 ?
N
In RX, 4.3Vat IC11 pin 31?
Y
4V output voltage at Q6 ?
Reliable solder at R171? No disconnected wiringto Q16 branch circuit?
Y
Y Y
Replace faulty components. In TX, 0V at IC11 pin31?
N
Check R11, L19, R74, Q13;
N
Reliable solder at PTT? No disconnected wiring to IC11branch circuit? Or replace IC11.
Check the value and soldering of Q6 、R9. Replace faulty components.
－ 37 －
Reliable solder at Q7, R53; No disconnected wiring to branch circuit?
Check IC11, peripheral components; or replace IC11.
TC- 446 Service Manual
1、 TX and RX unlock： （Caused by faulty common sector） Start
Adjust to correct software Correct software mode settings and freq range?
mode and freq;
Y 4.9V at IC2 pin2 ?
Y
N
12.8MHz at IC2
5V
N
pin13?
N Check 12.8MHz crystal, C130, TC6; Replace faulty components.
Y
at
Y
Q5(5C)?
Check L13, R191, C113,
After amplified by Q13,
N
VCO output OK?
output
In non-battery-sa ve mode, 5V (H level) at IC11pin6 ?
C117, C123; Replace faulty components.
Y
N
Y
Bad soldering joints at IC11 pin6? Correct software settings? If not, replace IC11.
Check VCO circuit
Data, clock, strobe pulse at IC2 pin8/9/10 OK?(triangle wave)
N
Check Q3, R65, Q2, R28, R66; Replace faulty components.
Check CP6 , CPU, C15, C16, C17 and wiring;
Y
1-4V CV control voltage (output)？
N
Check the soldering and value of the components between IC2 pin 3 to CV. Check the soldering of IC2. Replace faulty components.
Y High level at D 13 positive end ?
－ 38 －
TC- 446 Service Manual
Repair Example： 1) Symptom: unable to transmit even if PTT is pressed; wrong freq band found when reading from radio via PC; Cure: correct the freq band 2) Symptom: unable to lock freq, TR accessible sometimes, occasional TX or RX unlock; Cure: replace Q15(5108) 3) Symptom: unable to transmit even if PTT is pressed; freq range found OK when reading from radio via PC; no 5V output at Q5; Cure: replace Q5（717） 4) Symptom: unable to transmit even if PTT is pressed; freq range found OK when reading from radio via PC; 5V output at Q5; 5C voltage at X2 (12.8 crystal oscillator); Cure: replace X1 5) Symptom: able to transmit when PTT is pressed; freq range found OK when reading from radio via PC; 5C voltage OK; Voltage found at CV in RX but not within 0.8~4V; Cure: adjust TC2 to make CV within normal range 6) Symptom: Power-on OK; unable to lock freq when pressing PTT, TR accessible sometimes, occasional TX or RX unlock; Cure: replace Q15(5108)
－ 39 －
TC- 446 Service Manual VI. Power Supply： Fail to power on (no response while rotating power knob after plugging in power supply) Start
Plug positive end of power cable into positive connector while negative end into aluminum chassis or ground around PCB;
Turn off radio; 6.0V output at L15 Upper?
N
Check L15, C149, C120; Replace faulty components.
Y Switch on power;
N
Check power switch, D20, IC4; Replace faulty components.
6.0V at IC4 IN?
Y Check if short circuit occurs when IC4, C80, C79, branch circuit are grounded; Replace faulty components.
N
5V at IC4 OUT?
Y Check IC11 pin 71/ 72; 5V at IC9 pin 5 (RESET)?
Y Check IC11, X3 (7.3728 MHz crystal), peripheral R&C; Replace faulty components;
－ 40 －
N
Check if no-solder at IC11 and branch components; Replace faulty components.
TC- 446 Service Manual
Repair Example： 1) Symptom: Plug in 6.0 power cable, rotate power knob but unable to switch on power; voltage at L15 OK; no 7.5V at IC4 IN; power knob OK; Cure: replace D20 2) Symptom: Plug in 6.0 power cable, rotate power knob but unable to switch on power; Voltages at L15, IC4 IN OK; no 5V (5M) voltage at IC4; Cure: replace IC404 3) Symptom: Plug in 6.0 power cable, rotate power knob but unable to switch on power; 5V output at IC4; Voltage at IC9 OK; Cure: replace X3 （7.3728MHz crystal）
－ 41 －
TC- 446 Service Manual
Disassembly and Assembly Remove the Battery 1.
Turn the radio off.
2.
Slide the battery latches upwards.
3.
Pull the top part of the battery away from the radio’ s body and lift the battery from the radio. (See figure 1)
Figure 1
Disassemble main unit (aluminum chassis and PCB) 1. Remove the two screws at the base of the chassis. 2. Pull the volume knob and selector knob off. 3. Remove the antenna at top of the radio. 4. Remove the screw of the microphone jack cover and pull the jack cover off. (See figure 2)
Figure 2
－ 42 －
TC- 446 Service Manual
Pull the chassis upwards and then pull the chassis away from the front cover. (See figure 3)
Figure 3 The disassembly is shown as the figure 4.
Figure 4
Disassemble PTT button Push the PTT button in indicated direction until out of the cover. (See figure 5)
Figure 5
－ 43 －
TC- 446 Service Manual Assemble PTT button Paste double-coated tape to the cover. And then press the PTT button into the corresponding opening in the cover. (See figure 6)
Figure 6
Attach the battery 1. Fit the extensions at the bottom of the battery into the slots on the radio chassis. 2.
Press the top part of the battery towards the radio until a click is heard. (See figure 7)
Figure 7
－ 44 －
TC- 446 Service Manual
Exploded View 1
39
2
38 37
3
36
4 5
35
6 7 34 8 9
10 11 12 13
33
14 32
15
31
16
30
17 18 19
29 28
20
27 21 26 22
23
25
24
－ 45 －
TC- 446 Service Manual
Part List 2 No.
P/N
Description
Qty.
A
7102506000020
Machine screw M2.5*6.0mm
B
7102004020050
Self-tapping screw ST2.0*4.0mm Cross recess pan head (color zinc plating)
C
7102009001000
Machine screw M2.0*9.0mm (color zinc plating)
2
D
7102505000100
Machine screw M2.5*5.0mm T9 hexagonal head
2
1
6000051000010
TC500 Rear cover Black ABS700
1
2
6000374000000
TC308 Antenna cap Black TPUS95A
1
3
6100237000000
TC366 Antenna housing Black 85 degree TPU
1
4
7400018000000
TC446 PVC piece at main unit front case antenna hole
1
5
7000014000000
TC2110 Antenna core Ф 3.60mm (red copper plating)
1
6
6300007000030
TC446 Aluminum chassis Grinding ADC12
1
7
7500114000000
TC500 Cooling pad 2.00mm-thick Gap Pad1500 8.0*6.6mm
1
8
6100034000000
TC-500US Water-proof gasket Black 40 degree high-tensile silica rubber
1
9
7500013000000
TC2100 Positive electrode piece water-proof sponge 1.5mm-thick EVA
1
10
6201030000000
TC-500 Battery positive electrode piece 0.20mm SUS301 (nickel plating)
1
11
6000046000000
TC2100 Positive electrode piece support Black ABS
1
12
7207002200000
Nut M7.0*2.2mm
1
13
4303020000030
Volume switch TC-1688
1
14
7206002500010
Nut M6.0*2.5mm
1
15
4302030000010
Channel switch TC-368 RY-6933 tocos
1
16
4301040000020
PTT switch TC-278/TC-378 SKHLLBA010 ALPS
2
1 11
TC370 Speaker insulating pad 1.0mm-thick EVA Φ 17mm single-side 17
7400034000000
self-adhesive tape
1
18
5001010000020
Speaker 426539(036S23) 4Ω 0.5W D：36mm FOSTER
1
19
6000160000040
TC-368S Volume knob Black PC+ABS
1
20
6000158000040
TC-368S Channel knob Black PC+ABS
1
21
6201006000000
TC2088 Inner liner (knob) 0.25mm SUS304
2
22
6000050101000
TC500 Main unit front case Black HYTABS700
1
23
6100030000010
TC-500 PTT key Black 60 degree silica rubber
1
24
7400016000000
TC500 Mic mesh Unwoven cloth 0.3mm-thick Φ5.0
1
25
6000189000000
TC3000 Light guide Transparent PMMA
1
26
6000054000000
TC500 Mic cover Black ABS
1
27
7400075000000
TC500 Speaker mesh Unwoven cloth 0.05mm-thick Φ36
1
－ 46 －
TC- 446 Service Manual 28
6100075000000
TC-368 Mic gasket Black 30 degree silica rubber
1
29
5002110000030
Mic CZII-64AP-RoHS -60dB±2dB φ9.7*4.5mm
1
30
4210080000000
Lead with tin on both ends 80mm Black
1
31
4210080000300
Lead with tin on both ends 80mm Red
1
32
5205000000280
Speaker jack HSJ1456-010320
1
33
5205000000190
Earpiece jack HSJ1650-010020
1
34
7400133000000
TC500 PVC water-proof gasket PVC 0.3mm-thick Φ4.7
2
35
7500115000000
TC500 Battery contact pad Silica rubber 4.8*4.2mm
2
36
6201022000000
TC2100 Battery negative electrode piece 0.20mm SUS301 (nickel plating)
1
37
7400014000010
TC-500 Battery water-proof PVC piece 0.2mm-thick PVC 18.40*16.10mm
1
38
6000039000000
TC2108 Battery latch Black PC+ABS
1
39
7000015000000
TC500 Latch spring Ф 3.00×7×Ф 0 .35mm
1
－ 47 －
TC- 446 Service Manual
Packing
－ 48 －
TC-446 PC Board View Top Layer
49
PCB No.:4100500101600
TC-446 PC Board View Bottom Layer
50
PCB No.:4100500101600
TC-446 Schematic Diagram 1
2 R96
R19 NC 01 6 R
R61 1K
K
R43 330K
2 3 4
A0 A1 A2 GND
8 VCC TEST 7 6 SCL SDA 5
OUT
R88 4.7K
GND
C2
2.2K
0.01u
R176 100K Q35 DTC114EE
R7
220P
C14 100k 220P C18 27P IC1 IF SYSTEM TA31136FN
47K
R25 R26 C20 3.3K 3.3K 470P C57 4700p
Q47 NC
C52 33P
C4 0.01U
R12 100K
R10
C38 0.1U
C39 0.1U Q10 DTA114EE
C120 47uF/16V
R51 1K
C149 470P
R27
R28
3.3K
3.3K
Q1 UMG3N
R145
C198 1000P
C165
100K 2.2U/16V
Q2 UMG3N
VR2 47K
R65 2.7K C5 0.01u
C9 0.01U
R155 1.8M Q24 2SC5343(s) R33 3.3K R41 10K
R156 1.8M Q25 R152 39K 2SC5343(s)
C46 0.1U
C10 0.01U
R153 39K
C43 0.1U
R158 0.047u 39K
C34
ACTIVE FILTER
560P
R42 10K
C171 560P
C61 1000P
C69 1000P R144 1.8K
C87 R52 1K C62 1000P
R157 56K C144
R111
C74 1000P R5 C73 C56 330 1000P NC
C155 10u/10V Q19
R141 150K
R107 R39 C197 0 470p 1K
R138 3.3K
IC7
VR1
R37 10K
8.2K
C66
R94 470K 1 8 7 2 IC8 6 3 KIA6278F 5 4
R127 100
C162 0.047U
R89 1K
R163 15K
NJM2100V IC3
5
R192 0
R618 68K
C
C36 470P R24 33K
R106 0
Q41 2SK1588 R112 10 C237 0.047U
R93 47K
J1
TXD
SPK
B
J2
RXD
1
R50 1.5K C173 4.7U/16V
2SK1824
C194 0.1uF
R166 470
4
C168 0.022U 8
C169 C77 0.022U 1000P
R162 15K
D18 C76 C49 1SS372 1000P 0.1U
R110 0
R160 C167 0.022U 750K
1U/16V
C48 0.1U
R120 22K
Error : HYT.jpg file not found.
MODEL Part Name
SPK/4Ω
R165 2.2K
Q26 2SC5343(s)
C50 0.1U
J3
R174 2.2K
L14 1uH
D19 DAN222
C174 R161 15K
R175 100K
MIC1
Mic
C125 10u/10V
C35 470p
HYT Science & Technology Co. Ltd. PAGE
TC-446
Schematic Diagram
DATE
FILE NO. DRAWN BY 2
R150 470P R17 NC
C203 100u/6.3V C239 220P
R90 100
Q34 DTA114YE
A
1
C33 470P
C40 0.1u
Q39 NC
R2 C179 270K 100p
TC3 10P L31 4T TC4 10P L38 3T
C32 470p
C118 68uF/6.3V
R203 1.0K C84 Q12 DTC144EE 0.1u
1000P
L33 3T
C104 1P
Q27 3SK318 G2
R151 0 R32 3.3k
L34 3T
C250 0.1u
C122 0.039u
R113 10
C160 0.033U
R13 100K
R54 47K
C145 6P
C208
470P
C106 L40 L39 6P 100n 47n
Q40 2SA1362
R628
C156 0.018u R57 1K
R14 150K R15 100K
- + +-
R55 1.5K
L32 4T
C163 0.5P
R186 NC
NC
R76 100
C71 1000P
R98 20K
- + +NJM2902 VDD Vss
C159 10u/10V
TC5 10P
R78
C184 NC
C64 0.1u
Q20 2SC5343(s) C45 R508 R130 0.1U 5.6K 0
NC
5
C93 2P
C107 L35 5P 3T
Q21 2SK1824
R137 3.3k
0.033U
C94 0.5P
R187 NC Q37 NC
C105 3P
0.5P
D12 MA2S077
R181
NC
C8 0.01U
R142 150K C153 0.033U
C152 R136 3.3K
470P
NC
Q36 NC
1u/ 6.3V
R177 4.7K
C141 11P
C134 2P
C116 NC R178
8
5P
R147 100
Q23 R48 1.5K 3SK318
L43 1U
C164
C112
1.5u/10V
G2
L37 NC
C99 NC C233 0.1U
R135
10P
R85 C172 R159 2700P 39K R131 6.8K 1.8K Q46
C246 0.1U
R64 2.7K
C75 1000P
C158 0.047U
C157
C166 3300P
W/NC Q3 UPA572T
C190 NC
R97 R132 82K R602 27K 0 R134 680K
0
L15 600sg
B+
ACTIVE FILTER R66
DC 6.0V
C142 11P
VR6 NC
R180 R1844 NC
R627 56K R149 56k
TP1
D
C146
0.75P 2.4P
MIC
C85 1u/ 6.3V
C59 1000P
4T
NC
Q5 FMMT717
C86 C60 1u/ 6.3V 1000P
C143
L22
IC6 NC
R183 NC R179 C185 1 NC NC R185
MIXER
R108 L49 470P 330N 0
21.4M
XF1
R16 5600pF 270K C47
R36 C3 10K 0.01U
R83 NC
NC
3.3K R139 150K
L1 470
R601
Q4 FMMT717
R22 470K POWER1
820
C81 1000P
C150 0.033U
C54 33P
100K
CD1
C140
C136 3P
NC R182 C251
R146 330
R140 150K C151 0.033U
C44 0.022U
R167 220K
B
L10 600sg
C204 470P
IN
C53 33P
ANT1 C235 1000P L28 3T
L24 3T
0.75 C139 7.5
C12 0.01u
22n
C13
9
W/NC R615
D20
C80 1000P
C79 1000P
C110 1000p
C109 D9 C115 1000p MA2S111 15u/6.3V
CF1 455kHz(H) OUT
R3 PTT
C161 0.047U
C181 3900P
L4 0.22uH R75 100
C51 0.1u
R173 0 R77 0 R172 0
L25
R148 560K 2SC5108(Y)
0 C177 15u/6.3V
R40 10K
C196 1.5P
Q22
Q9 C1 DTA114YE 10u/10V
PTT
100K
IN
R84 4.7K C7 0.01U
R69 150
L23 4T
R623 100K R624 100K
R133 82K
0.1U C178
R35 100K D25 MA2S111
R18
C186 4P
C29 470p
C70 1000P
R100 10K R58 1K
IC4 XC6201P502PR
C135 10P
1K 2SC5343(s) Q18
R49 2.7K
R610 47K
IC5 AT2408
C137 0.01u
L16 L46 3.3U
+
470P
R53
R9 100K
TC2 10P
R6 2.2K
R604
R605
R204 10K
Q50 0
C68 1000P
R102 27K C114 C28 1000p
R205 NC L11 221SG
C89 1.5P C101 6.8
C55 C102 C506 15P 0.5P 33P
C72 1000P
20
1
R21 NC
R103 56k
X3
IC9
80
C175 33p
R4 47K
PST9140NR
C78 1000p L42 R20 NC NC
1
R109 1M
C111 1000p R104 22k
C30 470P
L7 601s
MONI 1M
R59 1K SELF
C
C189 5P
Q7 UMC4
L3 0 R125 R101 47 47K
C138 33P L2 5T
R617 27k
L12 601S
2SC5343(s)
IC11
M38223M4H
C27 470P
C147 D11 1000p MA77
C108
MONI R116
10
C92 1P
X1
C243 0.01U 0.01U
R197 0
C176 33P
C242
Q6 L47 2SJ243 100n R164
23nH
C188 D8 22P MA2S376 L48 100N
C232 4700p
R123 47
R70 R82 680 10
470P C231 470p
L17 D7 C19 100n MA2S376 18P
R8 100K
L20 NC
R80 10
D3 MA2S376
L6 601S
Q38 C133 NC 0.33u
L21 15nH
C31
R171 D2 82 MA2S376
L5 3.3U
TC1 10P
C121 1000P 40
60
L41 0.22u
R72 120K R74 100
R30 3.3K
C22 470P
C23 0
R31 3.3K
L29 C67 3.3nH 270P
C247 22u/6.3V C248 R616 22u/6.3V 270 C249 NC
C200 1u/6.3V
L45 47nH
L18 22n
C21 470P R79 R68 5.6K 150
L30 8T
Q31 RD07
R196 5.1
C183
120K R198
R29 3.3K
20.945MHz
W/NC
R105 47K
L19 22n
R129 NC
6P
Q32 RD01
C42 470P
R122 C98 330
Q17 2SC4988
R625 100K R626 100K L36 3T
R154 47k
C88 10p
C132 100p
C15 C16 C17 C180CP6 100P 100P 100P 100p 10K*4
R124 120K CP5 10K*2
D4 MA360
C90 7P
R609 R608 47K 47K
C240 0.01U 0.01U
8
7
C191 NC
VR3 68K
R99 4.7K
CP4 4.7K*2
C241
U1
10K*4 CP1
C11 0.01u
R607 47K
9 10 11 12
D24 GREEN
4.7K*4 CP3
0.5P
C193 R67 8P 330
C97 D5 6P MA2S077
R34 3.3k
IFO DEC 5 IFI 4 13 NDET VCC 14 3 NREC MIXO 2 15 E OSCO 16 1 MIXI OSCI
R121 4.7K C170 NC R606 47K
1 5678 2 3 4
D22 RED
R87 4.7K
R118 R45 470 10K
6P
82P 12 RSSI
VR4 68K
1 0.22u C123 R117 2.7k C230 R63 C117 8.2K C124 NC NC C127 4.7u/16V 1u/6.3V C126 NC D13 C113 0.33u L8 L13 NC 601s 1000p 601s R191 C65 47 R143 1000P NC
8
C91
R1
R62 470
C95 1P
C182
Q15 C100 2SC4226 22P
C96 6P
C207 R81 470P 3K
R194 0
C103 3P
Q14 2SC5108
680K C37 0.1U
R44 10K
DTC114EE C83 1000P
C82 1000P
9 16 IC2 IB31202
Q30
Q28 DTC114EE
120K
Q13 2SC5108
C63 1000P
8
47K
Q16 PRF957
C24 470P
C25 470P TP1 R38 10K R115 R114 47
R128
D
6
R11 R170 12K
L26 18n
D6 MA2S077
C195 2P
C253 10P
Q8 2SK508NV C187 10P
L50 1UH
1000P C255 10P
FILI
C252
3 2
OUT GND
AF
C254 2200P
1u/6.3V
5
10 R619 R47 7 QUAD FILO 6 820 820 C58 11
R622 18k
R56 1K
12.8MHZ
VDD VC
2.4PC192 R169 8.2k
X4 4 1
C202
4
0
R200 0.1U
23nH
BDZ3.0B
VR5 68K
3
R202 C26 1000P
330
L44
D10
3
4
5
51
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1 OF
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A
August , 2005
REV CHECKED
1
00
APPROVAL 8
PCB No.:4100500101600
TC- 446 Service Manual
Specifications 400 MHz ~420 MHz Frequency range
450 MHz ~470 MHz 136 MHz ~150 MHz 150 MHz ~174 MHz
Channel capacity (simplex)
16
Channel spacing
25KHz(wide)/12.5KHz(narrow)
Antenna impedance
50Ω
Microphone impedance
2KΩ
Operation voltage
6V DC
Frequency stability
±2.5×10
-6
Transmitter Carrier frequency error
±2.5×10- 6
Carrier output power
4.0W (Hi)/2.0W(Lo)
Modulation sensitivity
12±2mV
Modulation distortion
≤5%
Modulation limiting
≤5KHz(wide)/2.5KHz(narrow)
Bandwidth
≤16 KHz(wide)/8.5KHz(narrow)
Audio response
From 6 dB/oct. Pre-Emphasis ±3dB
Conducted spurious
≤7.5μW
emission Adjacent channel power
≤-65 d B Receiver
Reference sensitivity Unsquelch sensitivity
≤0.25μV(wide)/0.35uV(narrow) ≤0.4μV
Audio power
400mW (4Ω)
Audio distortion
≤5%
Modulation acceptance
≥│±7 KHz│(wide)/ │±3.5KHz│(narrow)
Audio response
From 6 dB/oct. De-Emphasis +2dB
Co-channel rejection
≥-8 d B
Blocking
≥85d B
Adjacent channel selectivity ≥60 d B(wide)/50dB(narrow) Spurious response rejection ≥60 d B Intermodulation rejection
≥60 d B(wide)/50dB(narrow)
－ 52 －
-8dB
