Motorola CP 140, Detailed Service Manual

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2-6 TROUBLESHOOTING TABLES
U451
ASFIC_CMP
1 VDD for analog circuits 3.00
2 DISC audio input 1.34 From U510
3 Ground for analog circuits GND
4 DACU output 0
5 DACR output 0
6 DACG output 2.38 (typ) Power set (TX mode)
7 VOX peak detector output 2.91
8 PLCAP for DC integrator 0.40
9 SQIN 0.01
10 Universal audio input/output 0
11 VDD for DACs 4.95
12 SQCAP 0
13 GCB2 general purpose output 0 Audio PA_EN (unsquelched)
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
IC Designator Pin Pin Function DC Voltage Comments (Condition)