Motorola solutions VX-261

To Next Page

VX-261 UHF FM Transceiver Service Manual 1

Introduction

This manual provides the technical information necessary for servicing the VX-261 UHF FM

Transceiver.

Servicing this equipment requires expertise in handing surface-mount chip components. At-

tempts by non-qualied persons to service this equipment may result in permanent damage not

covered by the warranty, and may be illegal in some countries.

Two PCB layout diagrams are provided for each double-sided board in this transceiver. Each side

of the board is referred to by the type of the majority of components installed on that side (“Side

A” or “Side B”). In most cases one side has only chip components (surface-mount devices), and

the other has either a mixture of both chip and leaded components (trimmers, coils, electrolytic

capacitors, ICs, etc.), or leaded components only.

As described in the pages to follow, the advanced microprocessor design of the VX-261 Trans-

ceiver allows a complete alignment of this transceiver to be performed without opening the case

of the radio; all adjustments can be performed from the front panel, using the “Alignment Mode”

menu.

While we believe the information in this manual to be correct, Motorola Solutions assumes no

liability for damage that may occur as a result of typographical or other errors that may be pres-

ent. Your cooperation in pointing out any inconsistencies in the technical information would be

appreciated.

Important Note

This transceiver is assembled using Pb (lead) free solder, based on the RoHS specication.

Only lead-free solder (Alloy Composition: Sn-3.0Ag-0.5Cu) should be used for repairs performed on this apparatus.

The solder stated above utilizes the alloy composition required for compliance with the lead-free specication, and

any solder with the above alloy composition may be used.

Contents

Specications................................................................................................................................................................. 2

Exploded View & Miscellaneous Parts ....................................................................................................................... 3

Parts List ....................................................................................................................................................................... 4

Block Diagram .............................................................................................................................................................. 5

Circuit Description ....................................................................................................................................................... 6

Alignment ...................................................................................................................................................................... 8

Cloning ........................................................................................................................................................................ 15

Main-2 Unit Circuit Diagram

(

Type “G6”: FR027830A

)

....................................................................................... 16

UHF FM Transceiver

VX-261

Service Manual

Motorola Solutions, Inc.

EC151U90A

Main Page

Need help?

Do you have a question about the Motorola solutions VX-261 and is the answer not in the manual?

The Motorola Solutions VX-261 UHF FM Transceiver is a robust and versatile two-way radio designed for reliable communication in various professional environments. This service manual provides comprehensive technical information for servicing the device, emphasizing the need for expertise in handling surface-mount chip components due to the advanced microprocessor design.

Function Description

The VX-261 is a UHF FM transceiver, meaning it operates on Ultra High Frequency (UHF) bands and uses Frequency Modulation (FM) for transmitting and receiving signals. It supports 16 channels, allowing for organized communication across different groups or functions. The device is designed for both transmission and reception, facilitating two-way radio communication. Its advanced microprocessor design enables complete alignment and adjustments to be performed directly from the front panel using an "Alignment Mode" menu, eliminating the need to open the radio's case for routine maintenance.

Important Technical Specifications

General:

Frequency Range: 403-470 MHz (Type “G6”)
Channels: 16 Channels
Power Supply Voltage: 7.4 V DC ± 10%
Current Consumption: <2.0 A (5 W TX)
Channel Spacing: 12.5 / 20 / 25 kHz
PLL Steps: 5 / 6.25 kHz
IP Rating: IP55 (indicating protection against dust ingress and low-pressure water jets from any direction)
Operating Temperature Range: -30 °C to +60 °C
Charging Temperature Range: 0 °C to +45 °C
Frequency Stability: ±2.5 ppm
RF Input-Output: 50 Ohm (unbalanced)
Dimensions (H x W x D):
- 58.4 x 109 x 32.3 mm (with FNB-V133LI-UNI)
- 58.4 x 109 x 39.9 mm (with FNB-V134LI-UNI)
Weight (Approx.):
- 285 g (with FNB-V133LI-UNI, Antenna, Belt Clip)
- 319 g (with FNB-V134LI-UNI, Antenna, Belt Clip)

Receiver (Measured by ETS 300 086):

Circuit Type: Double Conversion Super-heterodyne
Sensitivity (20 dB SINAD): -2 dBμV
Adjacent Channel Selectivity: 65 / 60 dB (W/N)
Hum and Noise: 45 / 40 dB (W/N)
Intermodulation: 65 dB
Spurious Image Rejection: 70 dB
Conducted Spurious: -57 dBm @≤ 1 GHz, -47 dBm @> 1 GHz
Audio Output:
- 700 mW (internal @16 Ohm, 5% THD)
- 500 mW (external @4 Ohm, 5% THD)

Transmitter (Measured by ETS 300 086):

Output Power: 5 / 1 W
Modulation: 16K0F3E / 14K0F3E / 11K0F3E
Maximum Deviation: ±5.0 kHz / ±4.0 kHz / ±2.5 kHz
Conducted Spurious Emissions: -36 dBm @≤ 1 GHz, -30 dBm @> 1 GHz
FM Hum & Noise: 45 / 40 dB (W/N)
Audio Distortion: <5% @1 kHz

Usage Features

The VX-261 offers several user-friendly features, including:

Front Panel Alignment: The radio's advanced microprocessor design allows for complete alignment and adjustments to be performed from the front panel using the "Alignment Mode" menu. This simplifies maintenance and reduces downtime.
Squelch Control: The device features 16 levels of squelch setting (0 to 15), allowing users to adjust the receiver's sensitivity to background noise. Level "0" opens the squelch, "1" sets the threshold, "14" provides tight squelch, and "15" enables carrier squelch.
Cloning Feature: The VX-261 includes a convenient "Cloning" feature, enabling the transfer of programming data from one transceiver (Source) to another (Destination) using an optional CT-27 cloning cable. This simplifies the setup of multiple radios with identical configurations. The cloning process involves specific steps:
1. Turn off both transceivers.
2. Remove the plastic cap and mounting screws from the MIC/SP jack on both transceivers.
3. Connect the CT-27 cloning cable between the MIC/SP jacks.
4. Press and hold the PTT and SIDE-1 switches while turning on the transceiver to activate Clone mode.
5. On the Destination transceiver, press the SIDE-1 switch (LED glows Green).
6. On the Source transceiver, press the PTT switch (LED glows Red, data transfers).
7. If successful, the LED turns off. If there's an issue, the LED blinks Red, prompting a check of connections and battery.
8. Turn off both transceivers, disconnect the cable, and replace the caps.
Battery Options: The transceiver supports Li-Ion battery packs (FNB-V133LI-UNI or FNB-V134LI-UNI), providing flexibility in power solutions.

Maintenance Features

The service manual highlights several key aspects of maintaining the VX-261:

Alignment Mode: The "Alignment Mode" menu, accessible via PC programming software (Motorola Solutions CE150), allows technicians to adjust various parameters without opening the radio. This includes:
- PLL Reference Frequency
- RX Sensitivity (RX Tune)
- Squelch (SQL/RSSI)
- TX Power (High/Low)
- Maximum Deviation (Wide/Narrow)
- CTCSS Deviation (Wide/Narrow)
- DCS Deviation (Wide/Narrow)
- DTMF Alignment
- Sequential Tone Deviation
Required Test Equipment: A comprehensive list of test equipment is provided for proper alignment, including an RF Signal Generator, Oscilloscope, Deviation Meter, In-line Wattmeter, 50 Ohm RF Dummy Load, Regulated DC Power Supply, Frequency Counter, Audio Signal Generator, AC/DC Voltmeters, UHF Sampling Coupler, IBM PC/compatible Computer with Windows OS, Motorola Solutions CE150 PC Programming Software, Motorola Solutions FIF-12 USB Programming Interface, CT-104A/CT-106/CT-171 PC Programming Cables, Motorola Solutions FRB-6 Tuning Interface Box, CT-160 Connection Cable, and Motorola Solutions CN-3 Antenna Connector.
Alignment Preparation & Precautions: The manual stresses the importance of connecting a 50-Ohm RF Dummy Load and in-line wattmeter during transmission procedures. It also advises against connecting the earth side of speaker leads to chassis ground due to the BTL amplifier circuit. Maintaining a stable ambient temperature (20~30 °C) and allowing the transceiver to acclimatize are crucial for accurate alignment. All alignments should be performed with oscillator shields and circuit boards firmly affixed.
Lead-Free Solder: The transceiver is assembled using Pb (lead) free solder, compliant with RoHS specifications. For repairs, only lead-free solder (Alloy Composition: Sn-3.0Ag-0.5Cu) should be used.
Component Replacement: Servicing and component replacement should only be performed by authorized Motorola Solutions representatives to maintain warranty validity and ensure proper functionality.
Data Integrity: A critical caution is issued regarding power supply during alignment: "Please never turn off the power supply during alignment. If the power supply is turned off during alignment, the alignment data will be corrupted."

The VX-261 is designed for professional use, offering robust performance and simplified maintenance through its advanced alignment capabilities and cloning features.