Motorola Commercial Series Service Information page 31

Troubleshooting Table for Board and IC Signals
IC Designator
U480
Dual Opamp
U490
Audio Power Amp
U510
Dual Opamp
1. All voltages are measured with a high-impedance digital voltmeter and expressed in volts DC relative to ground (0V).
2. Voltages are measured with a DC input voltage of 7.50 + .02 volts DC applied to the battery connector (J301).
3. All voltages are measured in the squelched receive mode, unless otherwise indicated.
Pin Pin Function
1 Unit 1 output
2 Unit 1 (-) input
3 Unit 1 (+) input
4 Ground
5 Unit 2 (+) input
6 Unit 2 (-) input
7 Unit 2 output
8 Vcc
1 Enable/shutdown
2 Bias reference
3 (+) input
4 (-) input
5 (-) output
6 Vcc
7 Ground
8 (+) output
1 Unit 1 output
2 Unit 1 (-) input
3 Unit 1 (+) input
4 Ground
5 Unit 2 (+) input
6 Unit 2 (-) input
7 Unit 2 output
8 Vcc
DC Voltage Comments (Condition)
2.48
2.48
2.46
GND
0.28
0.29
0
4.96
0.12 (Unsquelched)
3.26 (Unsquelched)
3.26 (Unsquelched)
3.27 (Unsquelched)
3.25 (Unsquelched)
7.48 (Unsquelched)
GND
3.29 (Unsquelched)
1.75
1.56
1.55
GND
1.55
1.56
1.38
4.96
3-15