RED PT500-2 Service Manual

PT500-2 Service Manual

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PT500-2 Service Manual

RED-RADIO

PT500-2 Service Manual

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PT500-2 Service Manual

Contents
Chapter 1

General

Chapter 2

Radio Overview

Chapter 3

Mode Introduction

Chapter 4

Disassembly For Repair

Chapter 5

Circuit Description

Chapter 6

PCB Layout

Chapter 7

Adjustment

Chapter 8

Bill Of Materials

Chapter 9

Charger

Chapter 10 Block and Schematic

Appendix 1 Abbreviations Appendix 2 Main Technical Indexes Appendix 3 Trouble
Shooting

Chapter 1 General

1.1 Introduction

This manual applies to the service and maintenance of PT500 radios, and is for the
engineers and professional technicians that have been trained by our company. In this
manual you can find all the information of product service. RED-RADIO reserve the rights to
modify the product construction and specification without notice in order to enhance product
performance and quality. Read this manual before repairing the product.

1.2 Attention

Safety
Do not touch the antenna connector with your skin directly. .
Do not reverse the power polarities.
Do not turn on the radio before the antenna and load connection is completed.

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Do not contact the damaged antenna when transmitting, or may make lightly burning on the
skin.

Electromagnetism Interference
It’s prohibited to use or repair the radio in the following places:

Hospital, health center, air port
Any area with a potentially explosive atmosphere (e.g. fuel and chemical storage and
transport devices etc.)
Any area of dynamite or exploder.

Change Components
All the components used in repair service should be supplied by RED-RADIO.

Other components of the same models available on the market are not surely able to use in
this product and we do not guarantee the quality of the product using such components.

1.3 Service

All the RED-RADIO products are subject to the service warranty.
After-sales service will be provided, and the length of warranty is stated by RED-RADIO.
The radio and its accessories are all in the warranty. However, in one of the following cases,
charge free service will be not available.

No valid service warranty or original invoice.
Malfunction caused by disassemble, repair or reconstruct the radio by the users without
permission.
Wear and tear or any man-made sabotage such as mechanical damage, burning or water
leaking.
Product serial number has been damage or the product trademark is difficult to identify.
Beyond the warranty time, lifetime service is still available with paid. And we also provide
service components to service stations and staff.

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Chapter 2 Radio Overview

1. PTT ( PUSH-TO-TALK) Button
To make a call, press and hold the PTT button, then speak into the microphone in normal
voice. Release the PTT button to receive signals.

2. Side Button 1 (Programmable Button)

3. Side Button 2(Programmable Button)

4. Channel Selector
Rotate to select channel 1~16.

5. Power/Volume Knob

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Turn clockwise to switch on the radio.
Turn counterclockwise till a click is heard to switch off the radio.
Rotate to adjust the volume after turning on the radio.

6. LED Indicator

LED Indicates Status/Alert. Green LED lights when a carrier is detected in the current
channel. Red LED lights during transmission. Orange LED flashes when receiving the
Radio ID 5-Tone signaling or 2-Tone signaling or MDC signaling. Green LED flashes
when scanning. Red LED flashes when low battery.

7. Speaker/Microphone Jacks

Used to connect the optional speaker/microphone.

8. MIC Input

Please keep your mouth about 10 cm (3-4 inches) away from the microphone input
to achieve the best voice quality. If the distance is too far or too close to the radio, it
will affect the voice quality.

Programmable Button Function

The dealer can program the Side Button 1, Side Button 2 and the Top Button with the
following Optional functions:

None (No Function)
Annunciation Selection
Talkaround
Call1/Call2/Call3/Call4
Lone Work
Emergency Call
Cancel Emergency Call
Scan
Noise Channel Delete
Call Forward
H/M/L Power Switch
Squelch Adjust
Monitor Momentary/Call Cancel
Monitor/Call Cancel
Squelch Off Momentary/Call Cancel
Squelch Off/Call Cancel
Lock Keyboard
Battery Check
Surveillance
CTCSS Scan/Forever Save CH
CTCSS Scan/Save CH

Chapter 3 Mode Introduction

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Mode combinations

Mode

Function

How to access

User Mode

For normal use

Power on

PC

Mode

Data
Programming
mode

Reading and writing
frequency data and other
functions

Receive instructions from
the PC

Test Mode

Used to tune the radio
using the PC.

Receive instructions from
the PC

Firmware
Upgrading
Mode

Upgrades the software
when new features are
added

Receive instructions from
the PC

User Mode：

You can enter User Mode (conventional communication mode) by turning on the power

switch. Users in the mode can use the defined function of the radio.

Data programming mode:

Before leaving the factory, the radio has been set in factory. However, due to different

requirements of users, functional parameters of the radio such as working frequency,
channels, CTCSS/DCS and auto scanning, etc. should be set again. Therefore, the company
has specially designed a set of PT500 programming software with friendly interface,
convenient operation and visualized display for setting functional parameters of the radio.

Steps for setting the functional parameters of the interphone by computer are as follows:

1. Install PT500 programming software on the computer.

2. As shown in the figure below, connect the radio to the computer through a special serial
or USB programming cable.

Comput

(RS232 seria

/USB po

Programm

cable

Radio

(Earphone /Program port)

Figure 3-1

3. Turn on the power of the computer.

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4. Turn on the power of the interphone.

5. Click on PT500 icon to perform the program.

6. In the main menu of the programming software, click on [Read] to read the parameters
of the radio into the computer; click on [Write] to write the parameters set in the computer
into the radio.

Caution:

1. Before editing for the first time, the data should be read from the interphone and properly
backed up.

2. If the edited data cannot work normally after being written into the interphone, please
open the backup data and rewrite them.

3. “Model Information” is the important information of the interphone and should not be
altered.

Test Mode

According to Figure 3-1, connect the radio to the computer with the special programming

cable.

Warning: Before entering the Test Mode, please first connect a high-frequency load of 50

ohm to the antenna port of the radio or connect the radio a certain test instrument.

With the PT500 Programming Software, you can enter the adjustment status in Computer

Test Mode to adjust the following parameters of the radio:

（1） Frequency stability
（2） RF transmitting high power
（3） RF transmitting Middle power
（4） RF transmitting Low power
（5） Maximum TX voice deviation

（6） VOX1(Tight)
（7） VOX10
（8） 2/5 tone deviation
（9） DTMF deviation
（10） MSK deviation
（11） DCS/LTR balance
（12） DCS deviation
（13） LSD deviation
（14） CTCSS(67.0Hz) deviation

（15） CTCSS(254.1Hz) deviation
（16） Battery warning level

（17） RX Sensitivity
（18） DCS RX middle level

（19） RX squelch 9 open level

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（20） RX squelch 9 close level
（21） RX squelch 1 open level
（22） RX squelch 1 close level

（23） RSSI(-120dBm)
（24） RSSI(-70dBm)

Firmware Upgrading Mode

The radio is equipped with an internal FLASH ROM, it can be upgraded if required.

1. Connect the radio to the PC with a proper programming cable, then power on the radio.

2. Run computer programming software.

3. Select the right “com port” you connected and the upgrading firmware and then click on

“E.P” to start downloading. 4. Turn off the radio and exit the programming software.

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Chapter 4 Disassembly For Repair

The radio is a kind of sophisticated communication equipment with small and fine mechanical

structure. You should assemble and disassemble it carefully during the maintenance
process. The Instruction for assembly and disassembly are as follows:

Installing/Removing the Battery Pack

To install the battery, please place it into the groove on the top of the radio chassis about

5mm away from latch.

If the radio has the belt clip installed, you will have to press one side of the clip, to raise it

and slide the battery in proper position.

Press the battery with your fingers and push the battery until you hear a latch click, the

battery is now installed.

Removing the battery pack：

If you want to remove the battery from the radio, first press the battery latch located on the
bottom of the radio, and then press down to slide the battery about 5mm to release the
latch.

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Notice: * Do not short-circuit the battery terminals or dispose the battery

in fire. * Do not disassemble the battery case.

Installing/Removing Antenna, Channel Selector, Power/Volume Knob

Screw the antenna out of the connector at the top of the radio by holding the bottom of the

antenna and turn it counter clockwise until apart.

Using a smooth tool or a tool protected with cloth to hold or prize up form the bottom of

channel selector or volume knob until apart，then screw the two screws under the channel
selector and volume knob using the special tool.

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Install external speaker/MIC

Open the cover of the jack for external speaker/MIC, and then insert the plug of the

external speaker or microphone into the jack on the radio. When inserting the accessory
plug, make sure it is properly aligned ( straight) to avoid internal damage to the connector
in the radio.

Installing/Removing the Belt Clip

Use the 2 screws (M2.5x8.0) supplied with the radio and fix these screws on the holes in the

radio clip and into the holes in the aluminum case. If you want to remove the clip from the
radio, just unscrew them, and remove the clip, you can put the screws back to make sure
you do not loose them.

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Installing/Removing the Chassis, PCB

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1． Remove the antenna, channel selector and power/volume knob and two screws under

the channel selector and volume knob.

2． Screw off the two screws at the bottom of the radio by a hexagon screwdriver.
3． Pry up the aluminum shell by peaking a straight screwdriver in the cross-slot at the

bottom of the aluminum shell, and then pull out the surface shell after placing the
aluminum shell inclined to the back；but please be careful not to snap off the cable of
the speaker.

4． Screw off the 11 screws on the PCB by a cross screwdriver.
5． Unsolder the endpoints of the antenna , PTT key board and speaker by an electric iron,

then remove the main board.

After the disassembly above, you can carry out corresponding reparation and debugging

according to the actual malfunction.

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Exploded View of the Parts

No.

Parts No.

Description

Qty.

1

604PT50001001

Cabinet asm.

1

2

2010CU600004X

Ear phone cabinet

1

3

2020PT500004X

O-ring Φ5X1.5

2

4

304060250001X

Volume screw M6X0.75X2.5 special shape brass

1

5

2010CU600006X

Volume knob black

1

6

304070250001X

Volume screw M7X0.75X2.5 special shape brass

1

7

2010CU600007X

Encoder knob black

1

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8

7100500240471

Anntenna

1

9

2030CU600003X

SMA RF socket

1

10

2020PT500003X

O-ring Φ7X1.5

1

11

2010CU600005X

radio top cover black

1

12

2020PT500002X

2 PIN power socket washer

1

13

301250607001X

machine screw M2.5X6.0 PB(+) black Ni-plate

2

14

7110CLP02001

CLP-02 clip asm.

1

15

70600CB03001

Battery CB-03 (OR CB-05 70600CB05001)

1

16

301200807001X

Machine screw M2.0X8.0

2

17

2030PT500001X

AL cabinet polishing ADC 12

1

18

1010500200102

Main PCB

1

19

2020PT500001X

cabinet waterproof ring

1

20

301200407001X

machine screw M2.0X4.0

14

Exchangeable part list

No.

Parts No.

Description

Qty.

604PT50001001

Cabinet asm.

1

2010PT500001X

Radio front cabinet black

1

2

2010CU600010X

Light-guider clear PC

1

3

2010CU600002X

PTT plastic key black

1

4

2010CU600003X

Ear phone plastic plug

1

5

2010CU600008X

Ear phone cover black

1

6

2020CU600001X

PTT silicon key block

1

7

306003301001X

Φ36mm air filter nylon weave

1

8

1211361601001

Speaker Φ36mm

1

9

2040CU600004X

7mm mic air filter Φ7.0X4.5X0.2

1

10

2020CU600004X

Mic waterproof washer

1

11

2010CU600009X

Battery locker black

1

12

2030CU600004X

Spring Φ2.3X10.5 Φ0.25

2

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604PT50001002

AL cabinet asm.

1

2030PT500001X

AL cabinet

1

2

2010CU600005X

Radio top cover black

1

3

2020PT500001X

Cabinet waterproof ring orange

1

4

2020PT500002X

Power socket washer

1

5

301250607001X

Machine screw M2.5X6.0

2

2010CU600006X

Volume knob

2010CU600007X

Encoder knob

7110CLP02001

CLP-02 Clip

Chapter 5 Circuit Description

5.1 Frequency configuration

The reference frequency of frequency synthesizer is provided by 12.8MHz crystal oscillator

X1 TCXO. The receiver adopts quadric mixing mode. The first IF is 38.85MHz, and the
second IF is 450kHz. The first local oscillation signal of the receiver is produced by frequency
synthesizer and the second local oscillation signal selects the 3rd harmonics of 12.8MHz of
crystal oscillator X1 TCXO. The signal of transmitter is produced by frequency synthesizer
directly.

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Figure 5. 1 Frequency configuration

5.2 Receiver（Rx）

The receiver is double conversion superheterodyne, designed to operate in the frequency

range of 400 to 470MHz,The frequency configuration in Fig 2

Figure 5.2 Receiver section configuration

Front End of Receiver

Signals from the antenna are filtered by BPF which consists of C235 C236 C233 C604 C252

C951 C234 C255 C260 L211 L209 L208 D201 D202 and D204 via RX/TX switch (D101
D102 and D103). After being filtered out the useless out-of-band signals, the signals are

amplified by LNA consisting of Q203 and external components.
Signals from LNA are filtered again by BPF which consists of C228 C226 C238 C229 C227
C239 C947 C259 C948 L214 L204 L203 D905 D206 and D206 before entering the 1st mixer

(Q202).

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The PWM wave is output by MCU composed of 58 foot and then commutated to adjustable

voltage after filtering to change the capacity of varactor diode D905 D203 D206 D201 D202

and D204 to control the center frequency of BPF.

1st mixer

The first IF (51.65MHz) signal is produced after mixing of the receiving signal from LNA and

the 1st local oscillation signal from frequency synthesizer. The first IF signal is filtered out

adjacent channel and other useless signals by crystal filter (XF201).

IF Circuit

The 1st IF signal from crystal filter is amplified by the first IF amplifier (Q201) before

processing of IC in IF( IC200，GT3136).

IF IC consists of the 2nd mixer, 2nd local oscillation, IF amplifier, limiter, frequency

discriminator and noise amplifier.

Frequency (12.8MHz) produced by TCXO(X1) is amplified and then selects 3rd harmonics

(38.4MHZ) as the second local oscillator signal source. The second IF signals (450kHz) are

generated after signals mixing of the second local oscillation (38.4MHz) and the first IF

(38.85MHz) in IC200. Audio signals are demodulated and outputted by IC200 after the

second IF signals are amplified and limited in IC200 and then filtered by ceramic

filter(450kHz).

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Figure 5.3 Schematic Diagram for IF System

Receiving Audio Signal Processing:

The audio processing circuit of receiver consists of IC300 and the peripheral circuit. Voice

signals from IC200 are sent to IC301 （ CTCSS signaling filter circuit ） and IC300-D

respectively after amplified in IC300-C. After that, the signals are removed of the HF and LF

components after amplification, de-emphasis and filtering by other units of IC300, and only

audit components from 300 to 3000Hz can be sent to audio power amplifier (IC302) after

amplified in Q300 and adjusted by volume potentiometers.

Figure 5.4 Schematic Diagram for Audio Processing of Receiver