Motorola M110 - User Manual

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Summary

Motorola M110;MC Micro Alignment (VHF)

General Procedures and Requirements

General procedures and requirements for performing adjustments and measurements, including voltage settings and component view.

Adjusting the Transmitter

Steps to adjust the transmitter, including preset potentiometers, supply voltage, and channel selection for transmit frequency.

Adjusting the Reference Oscillator

Procedure to adjust the reference oscillator frequency for correct transmit frequencies using a frequency counter.

Adjusting the Deviation

Steps to adjust the deviation for FM transmission using a modulation analyzer and audio oscillator.

Aligning the Receiver

Steps to align the receiver, covering the receiver VCO and the main receiver tuning.

Summary

Motorola M110;MC Micro Alignment (VHF)

General Procedures and Requirements

General procedures and requirements for performing adjustments and measurements, including voltage settings and component view.

Adjusting the Transmitter

Steps to adjust the transmitter, including preset potentiometers, supply voltage, and channel selection for transmit frequency.

Adjusting the Reference Oscillator

Procedure to adjust the reference oscillator frequency for correct transmit frequencies using a frequency counter.

Adjusting the Deviation

Steps to adjust the deviation for FM transmission using a modulation analyzer and audio oscillator.

Aligning the Receiver

Steps to align the receiver, covering the receiver VCO and the main receiver tuning.

This document outlines the alignment and maintenance procedures for the Motorola M110/MC micro radio, specifically for VHF operation. It serves as a service manual transcript, providing detailed steps for adjusting various radio components to ensure optimal performance.

Function Description

The Motorola M110/MC micro radio is a communication device designed for VHF frequencies. The manual details procedures for aligning its transmitter, reference oscillator, deviation, and receiver components. These alignments are crucial for ensuring the radio transmits and receives signals accurately and efficiently, adhering to specified power levels, frequencies, and modulation characteristics. The radio's design incorporates several adjustable components (pots, coils) that allow for precise tuning, making it a serviceable unit for professional use.

Important Technical Specifications

The alignment procedures specify several key technical parameters and requirements:

Power Supply:

All adjustments are to be performed at a supply voltage of 13.2 ±0.1 VDC, unless otherwise specified.
For the MAU1, six-watt model, the supply voltage for transmitter adjustment is 12.6 VDC.
Recommended power supplies include the R1001B (or S1347D for radios with 10 watts or less power).

Transmitter Power Settings (HI PWR - R453 adjustment):

MAU0: 1.0 W
MAU1: 6.0 W
MAU2: 10.0 W
MAU3: 25.0 W

Transmitter Power Settings (after voltage limit adjustment - R453 adjustment):

MAU0: 1.1 W
MAU1: 5.6 W
MAU2: 10.7 W
MAU3: 26.8 W

Low Power Channel Output (R455 adjustment):

MAU1 and MAU2: 0.7 to 1.4 watts (nominal 1.0 watt)
MAU0: 70 to 140 mW (nominal 0.1 watt)

Steering Line (SL) Voltage:

Transmitter VCO (L210) adjustment: 7.0 VDC (highest transmit frequency), at least 2.5 VDC (lowest transmit frequency).
Receiver VCO (L201) adjustment: 7.0 VDC (highest receive frequency), at least 2.5 VDC (lowest receive frequency).
Voltmeter impedance for SL measurements: 11 megaohms or greater.

Reference Oscillator Stability:

Models with 2 ppm stability use R163 for adjustment.
Other models use L151 for adjustment.
Target transmit frequency accuracy: ~100 Hz.

Deviation Settings (VCO MOD - R302 adjustment):

25 kHz channel spacing: ~4.6 kHz
20 kHz channel spacing: ~3.7 kHz
12.5 kHz channel spacing: ~2.3 kHz
Audio oscillator input for deviation adjustment: 1 kHz at 800 mV RMS.

Deviation Settings (REF MOD - R305 adjustment):

Adjusted for flattest square-wave response with minimum tilt, using a 200 Hz audio oscillator at 800 mV RMS.

Receiver Injection Filter Coils (L6, L5, L7) Voltage:

Peak for maximum DC voltage, typically between 2.1 and 3.5 VDC.

Receiver IF Filter Coils (L1, L3, L4, L5) Voltage:

Adjust to peak the AC voltmeter reading, maintaining approximately 30 mV RMS.

Receiver Audio Output:

Adjust volume control for approximately 1 volt RMS across a 2-ohm load (during deviation adjustment).
Adjust volume control for 1.7 volts RMS across a 2-ohm load (during squelch adjustment).

Squelch (R59 adjustment):

CCITT-weighted SINAD at unsquelch point: 8 to 12 dB.
RF signal level for squelch adjustment: 1 mV, modulated with 1 kHz tone at 60% of full system deviation.

Full System Deviation for Receiver Adjustment:

25 kHz channel spacing: ~5 kHz
20 kHz channel spacing: ~4 kHz
12.5 kHz channel spacing: ~2.5 kHz

Usage Features

The manual primarily focuses on alignment procedures rather than end-user operational features. However, it implicitly describes several usage-related aspects:

Channel Selection: The radio supports multiple transmit and receive channels, with specific procedures for selecting channels with the highest or lowest frequencies for alignment. The presence of a "channel selector switch" is indicated.
RF Power Options: The radio can have an optional MAB889 slaved RF power option, which affects how high and low power channels are managed and adjusted.
Tune-up PROM/Programming: For multi-channel radios with specific receive bandwidths, a tune-up PROM might be required, or the tune-up frequency can be programmed into the radio (EZ models only). EV models have a pre-programmed tune-up channel accessible by shorting TEST pins on the command board.
Carrier Squelch Mode: The radio features a carrier squelch mode, which can be enabled via a front panel switch.
Adjustable Controls: The presence of pots (R453 HI PWR, R455 LO PWR, R463 VOLT LIMIT, R302 VCO MOD, R305 REF MOD, R59 SQUELCH) and coils (L210 TX, L201 RX, L151, L1-L7, L54) indicates a high degree of user-serviceability and fine-tuning capability.

Maintenance Features

The document is essentially a guide for radio maintenance, focusing on precise alignment steps:

Test Equipment Recommendation: A list of recommended test equipment is provided, including a Communication System Analyzer (R2001D or R2200B), Mobile Test Set (GTF180A), Adapter Cable (GTF244A), Psophometric Filter (PFT4053A), Select 5 Test Unit (FTP3005B), and Digital Multimeter (R1037 or R1024B). This highlights the specialized tools required for proper maintenance.
Disassembly Instructions: For tune-up procedures, the radio must be "completely assembled except for the chassis cover, top cover of the synthesizer compartment, and the radio sleeve." This indicates a modular design that facilitates access to internal components for adjustment.
Component Identification: Pictures A, B, and C (though only A and B are provided in the extract) are referenced to show the locations of components and alignment points on the RF board and command board, which is critical for technicians.
Step-by-Step Alignment: The manual provides a meticulous, numbered sequence of steps for each alignment procedure (transmitter, reference oscillator, deviation, receiver VCO, receiver), ensuring a systematic approach to maintenance.
Verification Steps: Numerous steps involve verifying voltage readings, power outputs, and frequencies to confirm that adjustments have been made correctly and that the radio is operating within specifications.
Troubleshooting Guidance: Implicit troubleshooting is embedded in the verification steps. For example, if a voltage reading is outside the specified range, further adjustment or investigation is implied. The instruction "If + and - deviation readings differ, use only the higher reading" provides specific guidance for a common measurement anomaly.
Safety and Best Practices: The initial note "Key the radio while making adjustments or measurements" is a crucial operational instruction for technicians. The warning about potential "tipo errors" and the disclaimer regarding responsibility for damages underscore the importance of careful execution and professional expertise during maintenance.
Specific Potentiometer and Coil Adjustments: The document details which specific potentiometers (e.g., R453, R455, R463, R302, R305, R59) and coils (e.g., L210, L201, L151, L1-L7, L54) to adjust for each parameter, providing clear instructions for technicians. The direction of adjustment (CW or CCW) is also specified.