Reassemble per the mechanical exploded view (Section 8). Apply power. Radio powers on. Then perform the “Quick Check” (Section 1.2): Listen for proper squelch open, transmit current draw (should be <1.4A at 4W UHF).
The logic board requires a regulated 3.3V from the voltage regulator (IC400). The service manual directs you to test point TP1 (SW B+) — should be battery voltage. Then test TP4 (Vcc Logic) — should be 3.3V. motorola gp3188 service manual
Confirm the battery is charged (>7.0V on DMM). Check battery contacts for corrosion. If OK, proceed. Reassemble per the mechanical exploded view (Section 8)
For technicians, hobbyists, and fleet managers, the is not just a PDF file—it is the most critical tool in the toolbox. Unlike a basic user guide that explains how to turn the volume up, the service manual provides detailed schematics, alignment procedures, component-level repair instructions, and troubleshooting flowcharts. Then perform the “Quick Check” (Section 1
The schematic shows that the reset circuit is driven by a TL7705 reset IC (or equivalent). If its output is stuck low, replace it. The parts list gives the Motorola part number: 5109626Z02.
