Motorola Astro Digital Mobile Radio Xtl5000 Basic 6881096c73 O Manual

Chapter 2 Basic Maintenance
2.1 Introduction
This section of the manual describes preventive maintenance, handling precautions, and some basic 
repair procedures and techniques. Each of these topics provides information vital to the successful 
operation and maintenance of your radio.
NOTE:For board- and component-level repair of the radio, refer to the Detailed Service Manual (see 
”Related Publications” on page xii).
2.2 Preventive Maintenance
Radios are shipped from the factory with a worst-case...

June 11, 20036881096C73-O
2-2Basic Maintenance: Handling Precautions
2.2.2.2  Cleaning Internal Circuit Boards and Components
Isopropyl alcohol may be applied with a stiff, non-metallic, short-bristled brush to dislodge embedded 
or caked materials located in hard-to-reach areas. The brush stroke should direct the dislodged 
material out and away from the inside of the radio. Be careful not to break off electrical components.
Alcohol is a high-wetting liquid and can carry contamination into unwanted...

6881096C73-OJune 11, 2003
Basic Maintenance: Handling Precautions2-3
NOTE:Be sure that the table and floor mats are properly grounded.
When these items are not readily available, observing the following techniques will minimize the 
chance of damage:
 If a static-sensitive device is to be temporarily set down, use a conductive surface for 
placement of the device.
 Make skin contact with a conductive work surface first and maintain this contact when the 
device is set down or picked up.
 Always wear a...

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2-4Basic Maintenance: Handling Precautions
Notes 

Chapter 3 Basic Theory of Operation
3.1 Introduction
The ASTRO XTL 5000 radio combines the controller and RF sections into a single board and 
contains three modules: a daughtercard, RX VCO module, and TX VCO module. It is important to 
correctly identify the malfunctioning region before replacing expensive modules. To assist with radio 
repair, descriptions of the sections contained on the XTL 5000 uniboard are listed below.
3.2 General Overview
The XTL 5000 radios are wideband, synthesized, fixed-tuned...

June 11, 20036881096C73-O
3-2Basic Theory of Operation: Controller Section
3.3 Controller Section
3.3.1 Introduction
The XTL 5000 radio is primarily a uniboard design, consisting of isolated topside and bottomside 
controller sections and various RF sections. The controller section will be discussed here in basic 
terms, to assist in the overall understanding of what is contained in the controller section, and a 
simplified purpose of its elemental parts. Some limited warnings and recommendations are...

6881096C73-OJune 11, 2003
Basic Theory of Operation: Surrounding Controller Region 3-3
3.4.1 Microprocessor
The microprocessor consists of an MCORE-based controller and a DSP that communicates with the 
memory ICs via a 16-bit data bus. It also communicates to peripheral ICs on the main board via an 
SSI and SPI bus. This microprocessor contains a fixed amount of one-time programmable ROM and 
a small section of RAM. However, the microprocessor does not contain the radio software setting as 
programmed...

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3-4Basic Theory of Operation: Surrounding Controller Region
NOTE:A control head is not necessary for the function of the radio (in special application 
configurations), but the controller section is critical for the RF sections to function. This is an 
important point since repairs and troubleshooting of the RF sections usually requires that the 
controller section is operating correctly.
3.5.2 Voltage Regulation
The uniboard contains the following voltage regulators: 9 V, 5 V,...

6881096C73-OJune 11, 2003
Basic Theory of Operation: Surrounding Controller Region 3-5
3.5.4.1  Audio
The audio circuitry of the controller section contains the following:
Audio PA
 Codec
 MIC Audio
 DSP controlled EEPOTS
 AUX RX, AUX TX, and external speaker paths
 FILT audio.
This allows interfacing to the existing accessories made by Motorola, such as VRS, SIREN, and 
Consolette. It also allows for select compatibility with aftermarket modems.
3.5.4.2  Program Cable
If the programming cable is...

June 11, 20036881096C73-O
3-6Basic Theory of Operation: Analog Mode of Operation
3.6 Analog Mode of Operation
3.6.1 Receive Operation
When the radio is receiving, the signal comes from the antenna through the RF PA output network 
located in the power amplifier section to the front-end receiver assembly. The signal is then filtered, 
amplified, and mixed with the first local oscillator signal generated by the receiver voltage controlled 
oscillator (VCO). The resulting intermediate-frequency (IF) signal...