Motorola EP450

HKLN4216A November 24, 2003
VHF Troubleshooting Tables: Troubleshooting Table for Board and IC Signals 5-15
U451
ASFIC_CMP
14 GCB1 general purpose output 0
15 GCB0 general purpose output 3.00 BW select (25 kHz mode)
16 Squelch channel activity output 0 To U401-84
17 Squelch detect digital output 0 To U401-83
18 PL/low speed data I/O 1.50
19 High speed data I/O 3.00
20 Chip select 3.23 From U401-2
21 Serial clock input 0
22 Serial data input 3.23
23 Ground for clock synthesizer GND
24 Loop filter cap for clock syn 0.74
25 PLCAP2 for LS integrator 1.17
26 Not used 0
27 Vdd for clock synthesizer 3.00
28 Clock synthesizer output 1.70
29 1200 Hz ref for MDC decode 3.00
30 GNDDO GND
31 Ground for digital circuits GND
32 Vdd for analog switches 4.96
33 Vdd for digital circuits 3.00
34 16.8 MHz master clock input 1.54
35 GCB3 general purpose output 3.00 Internal MIC enable
36 TX audio return from option 0
37 GCB4 general purpose output 0
38 GCB5 general purpose output 0
39 RX audio send to option 1.48
40 Modulation output 1.50 To U201-10
41 RX audio out to power amp 1.51
42 Flat TX audio return from option 0.20
43 RX audio return to option 1.50
44 Flat TX audio send to option 1.50
45 Vdd for audio path I/O filters 3.00
46 Mic audio input 1.50
47 Ground for audio path I/O filters GND
48 Ext mic audio input (not used) 0
Table 5-4. Troubleshooting Table for Board and IC Signals (Continued)
IC Designator Pin Pin Function DC Voltage Comments (Condition)