Motorola CP040 - Page 51

Troubleshooting Tables for Board and IC Signals (includes Controller, DC Regulation and Audio) 2-5
U251
VCO / Buffer
12 Prescaler output 2.26
13 TX switch output (NU) 0.06
14 Vcc_BUFFERS 3.00
15 TX VCO emitter 0 (RX mode)
16 TX VCO base 0 (RX mode)
17 GND_LOGIC GND
18 Vcc_LOGIC 3.00
19 TRB input 0.03 From U201-2 (RX mode)
20 FLIP input GND
U310
5V Regulator
1 Vin 7.48
2 Ground GND
3 Control input 7.48
4 Bypass capacitor 1.26
5Vout 4.96
U320
3.3V Regulator
1 Ground GND
2 Feedback 1.23
3 Tap (NU) 0
4 Vin 7.48
5 Vout 3.23
6 Sense (NU) 0
7 Error (reset output) 3.20
8 Shutdown input 7.48
U330
3V Regulator
1 Vin 7.48
2 Ground GND
3 Control input 7.48
4 Bypass capacitor 1.26
5 Vout 3.00
IC Designator Pin Pin Function DC Voltage Comments (Condition)