Motorola EP450 - Page 40

HKLN4216A November 24, 2003
VHF Troubleshooting Tables: Troubleshooting Table for Board and IC Signals 5-9
U201
Freq Synthesizer
24 Ref osc XTAL2 0
25 Ref osc warp output 3.00
26 Superfilter cap 4.48
27 Superfilter base (NU) 3.76
28 Superfilter output 4.52
29 NC2 0
30 Superfilter input 4.96
31 NC3 0
32 Prescaler input 1.97
33 Prescaler ground GND
34 Prescaler Vdd 2.99
35 Prescaler Vref (NU) 1.97
36 Digital Vdd 2.99
37 TEST1 (NU) 0.01
38 TEST2 (NU) 0
39 Bias 2 3.38 (typ) (1.34 V in TX mode)
40 Bias 1 1.50 (typ) (3.20 V in TX mode)
41 Modulation output 3.42 (typ) (1.62 V typ in TX mode)
42 CCOMP (NU) 0.05
43 Steering line IOUT 9.62 (typ) Depends on frequency
44 PD ground GND
45 Steering line IADAPT 9.62 (typ) Depends on frequency
46 Adapt switch (NU) 0
47 Voltage from charge pump 12.8
48 AUX1 output (NU) 2.98
U251
VCO / Buffer
1 TX VCO current adjust 4.50
2 RX VCO current adjust 4.35
3 Superfiltered input 4.51
4 Collector RF in amp 4.35
5 RX VCO base 1.27
6 RX VCO emitter 0.48
7 RX switch output (NU) 0
8 RX buffered VCO output 3.36
9 GND_FLAG GND
10 TX buffered VCO output 3.36
11 GND_BUFFERS GND
Table 5-4. Troubleshooting Table for Board and IC Signals (Continued)
IC Designator Pin Pin Function DC Voltage Comments (Condition)