
UHF1 Troubleshooting Tables:
Troubleshooting Table for Board and IC Signals (UHF1)
12-5
(DTMF decoder)
2
IN-
1.6
3
GS
1.6
4
Vref
1.6
8
OSC1
1.6
3.579545 MHz input
10
VSS
0
11
TOE
3.3
17
STD
High
At DTMF detecting
18
EST
3.3
19
ST/GT
3.3
20
VDD
3.3
FL701(VCTCXO)
1
VCON
1.9
2
GND
0
3
OSC out
osc
Generate the 12.8 MHz
4
VCC
5
Q206(N/S SW)
E
GND
0
B
N/S SW
12.5 kHz: Low
C
Collector
12.5 kHz: High
25 kHz: Low
Q304
E
+5V
5
At RX Mode
B
To Q305 collector
Low
C
RX_B+
4.7
Q305
E
GND
0
At RX Mode
B
RX_EN
High
C
To Q304 base
Low
Q503
E
GND
0
At TX Mode
B
TX_EN1
High
C
To Q706 base
Low
Q407
E
+5V
5
At TX Mode
B
To Q408 collector
Low
C
TXVB
4.7
Q408
E
GND
0
At TX Mode
B
TX_EN2
High
C
To Q407
Low
Table 12-4. Troubleshooting Table for Board and IC Signals (UHF1) (Continued)
IC Designator
Pin
Pin Function
DC Voltage (V)
Comments (Condition)
Содержание CP Series
Страница 1: ...Portable Radios Detailed Service Manual EP350 ...
Страница 2: ......
Страница 8: ...iv Notes ...
Страница 18: ...xiv Notes ...
Страница 26: ...Notes 2 4 Test Equipment Service Aids and Service Tools Service Aids ...
Страница 72: ...7 26 Notes ...
Страница 110: ...10 23 Notes ...
Страница 127: ...Circuit Board Schematic Diagram and Parts List UHF1 403 447 MHz 13 2 Figure 13 4 VCO and PLL Schematic Diagram ...
Страница 128: ...13 3 Circuit Board Schematic Diagram and Parts List UHF1 403 447 MHz Figure 13 5 Transmitter Schematic Diagram ...
Страница 131: ...Circuit Board Schematic Diagram and Parts List UHF1 403 447 MHz 13 6 Figure 13 8 Switches and Battery Schematic Diagram ...
Страница 153: ......