Chapter 5 Troubleshooting Procedures; Introduction; Handling Precautions; Voltage Measurement And Signal Tracing - Motorola ASTRO XTS 2500 Service Manual

Chapter 5 Troubleshooting Procedures

5.1

Introduction

The purpose of this chapter is to aid in troubleshooting problems with the ASTRO XTS 2500/
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XTS 2500 digital portable radio. It is intended to have enough detail to localize the malfunctioning
circuit and isolate the defective component.
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C a u t i o n
This manual is to be used in conjunction with the ASTRO XTS 2500/XTS 2500
Radio Basic Service Manual (Motorola part number 6816984H01), which uses the pass/fail service
approach to radio problems.
5.2

Handling Precautions

Complementary metal-oxide semiconductor (CMOS) devices, and other high-technology devices,
are used in this family of radios. While the attributes of these devices are many, their characteristics
make them susceptible to damage by electrostatic discharge (ESD), or high-voltage charges.
Damage can be latent, resulting in failures occurring weeks or months later. Therefore, special
precautions must be taken to prevent device damage during disassembly, troubleshooting, and
repair. Handling precautions are mandatory for this radio, and are especially important in low-
humidity conditions. DO NOT attempt to disassemble the radio without observing the following
handling precautions:
1. Eliminate static generators (plastics, Styrofoam, etc.) in the work area.
2. Remove nylon or double-knit polyester jackets, roll up long sleeves, and remove or tie back
loose hanging neckties.
3. Store and transport all static-sensitive devices in ESD-protective containers.
4. Disconnect all power from the unit before ESD-sensitive components are removed or
inserted, unless otherwise noted.
5. Use a static-safeguarded workstation. We recommend using a wrist strap, two ground cords,
a static-control table mat, and a static-control floor mat.
6. Always wear a conductive wrist strap when servicing this equipment. The Motorola part
number for a replacement wrist strap that connects to the table mat is 4280385A59.
7. When performing hot-air repair in close proximity to the backup battery (reference number
M500), remove the backup battery before performing any rework to avoid damaging the
battery.
5.3

Voltage Measurement and Signal Tracing

It is a good idea to check the battery voltage under load. This can be done by measuring the
OPT_B+ _VPP pin at the universal (side) connector (pin 4). The battery voltage should remain at or
above 7.0 Vdc. If the battery voltage is less than 7.0 Vdc, the battery should be recharged or
replaced, as necessary, prior to analyzing the radio.
Most of the ICs are static sensitive devices. Do not
attempt to troubleshoot or disassemble a board
without first referring to the following Handling
Precautions section.
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Digital Portable