HYT TR-50 Service Manual
TR-50
PORTABLE REPEATER
Contents
General……………………………………………………………………………..1
Brief Introduction…………………………………………………………………..2
Theory of Operation………………………………………………………………4
Alignment & Calibration…………………………………………………………..6
Part List 1………………………………………………………………………….9
Assembly and Disassembly for Repair………………………………………11
Exploded View……………………………………………………………………12
Part List 2…………………………………………………………………………13
Packing……………………………………………………………………………14
PCB Board View…………………………………………………………………15
Schematic Diagram……………………………………………………………...17
Specifications…………………………………………………………………….19
TR-50 General
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General
Manual Scope
This manual is intended for use by experienced technicians familiar with similar types of
communication equipment. It contains all service information required for the equipment and is current
as of the publication date.
User Safety Information
The following precautions are recommended for personnel safety:
z DO NOT transmit until all RF connectors are verified secure and any open connectors are
properly terminated.
z SHUT OFF and do not operate this equipment near electrical blasting caps or in an explosive
atmosphere.
z When in vehicles with an airbag, do not place a repeater in the area over an airbag or in the airbag
deployment area.
z DO NOT expose the repeater to direct sunlight for a long time nor place it close to a heating
source.
z DO NOT use any repeater with a damaged antenna. If a damaged antenna comes into contact
with your skin, a minor burn may result.
z This equipment should be serviced by a qualified technician only.
TR-50 Brief Introduction
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Brief Introduction
1. LED Indicator
The following table indicates LED indication and corresponding radio status.
LED Status
Red Power on
Green Receive (or in battery save mode)
Blue Transmit
2. Power /Volume Control Knob
Rotate the Power/Volume Control Knob clockwise until a “click” is heard to turn the repeater on. Then
the LED turns red when the power is on. Rotate counter-clockwise to turn the repeater off until a “click” is
heard. When the repeater is on, turn the Knob to adjust volume. (Suggestion: adjust volume to the
lowest while Monitoring is unnecessary.)
3. RJ45 Programming I/O Port
Used by the dealer to program the repeater’s receiver and transmitter respectively.
4. Speaker
Used to monitor the communication status of current channel.
5. Rx Antenna Connector
N/F type RF connector.
6. Tx Antenna Connector
N/F type RF connector. Applied as antenna port when duplexer is installed.
TR-50 Brief Introduction
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7. AC Power Inlet
After correctly connecting AC power supply, turn on the switch to enter AC power supply mode.
8. AC Power Switch
9. DC Power Inlet
The float charging function will operate in AC power supply mode with external gel cell batteries
connected. When AC mains power is lost, it will auto-revert to the back-up battery supply without
mechanical relay.
TR-50 Theory of Operation
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Theory of Operation
I. Power Control
The control board draws a general 13.8V dc power supply, which is converted through U1, a 3-terminal
regulator, to 8.0V dc for the receiver and transmitter.
Fig. 1 Power Supply Block Diagram
II. Relay Control
When a valid signal is detected, the COR goes low and trigger PTT of the transmitter. At the same
time, the audio output from discriminator is routed to MIC input of the transmitter. The trimmable
resistor VR3 is used to adjust the receive audio output to the proper level for transmit audio deviation.
III. Float Charging Function
The TR-50 provides selectable AC (100-240V ac) power supply. Normally users can equip battery
back-up system connected to the external DC jack with floating charge function in the mean time. This
provides auto-revert to DC battery once the AC mains fails.
IV. Fan Control
This repeater provides three options of cooling fan control: PTT controlled, temperature controlled and
continuous operation. The power supply of the fan is controlled through a 5V voltage detector,
HT7050A. When the input is above 5V, the output is high-Z; when lower than 5V, the output goes low.
TR-50 Theory of Operation
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V. AF Amplification
The receive audio is routed to another AF amplifier NJM386M, which is convenient for the users to
monitor the activities of current channel.
VI. Definition for control ports
The definition of all the pins goes as follows:
1. J3 1pin——NC
2pin——TLED-
3pin——MIC+ Transmitter
4pin——PTT
5pin——TLED+
6pin——RLED+
7pin——SP+
8pin——RLED- Receiver
9pin——Rx AF
10pin——COR
2. J6
1pin——ETxD
2pin——ERxD Transmitter
3pin——ATxD
4pin——ARxD Receiver
3. RJ45 EXT
1pin——ARxD
2pin——MIC
3pin——ATxD
4pin——ERxD
5pin——GND
6pin——ETxD
7pin——EXT PTT
8pin——SB+（8V）
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