Albrecht PMR Service Manual

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SERVICE MANUAL

2-WAY PORTABLE

HANDHELD PMR

RADIO

TECtalk

Jan. 2000

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CONTENTS

1. GENERAL

1.1 General

1.2 Characteristics and features

2. SPECIFICATION

2.1 General Specification

2.2 Electrical Specification

3. OPERATION

3.1 Push buttons

3.2 ICONS on LCD

3.3 Key Functions

3.4 Setting and Operation

4. ADJUSTMENT

4.1 Frequency synthesizer

4.2 Transmitter

4.3 Transmitter test

4.4 Receiver

4.5 Receiver test

4.6 Symptoms, check point & corrections

5. DESCRIPTION OF RADIO CIRCUIT

5.1 Frequency Synthesizer

5.2 Receiver

5.3 Transmitter

6 CHANNEL DATA

7 ANNEX: CIRCUIT LAYOUTS AND SCHEMATIC DIAGRAM

1. GENERAL

1.1 GENERAL

TECtalk is a minimum sized two-way portable handheld radio.

The frequency range is 446.00625 ~ 446.09375MHz, 8 UHF operating channels

according to European PMR 446 international agreement are available.

1.2 CHARACTERISTICS AND FEATURES

a) All active devices in this radio are semiconductors and high density IC.

b) The radio is designed very compact and the weight is approximately 140g including

battery.

c) The unit is equipped with CPU HD404889 from HITACHI.

d) Power supply is designed for battery operation with 4 cells alkaline (1.5V AAA)

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batteries or

4 cells rechargeable NiMH batteries of the same size.

e) The radio is shipped with fixed (non-detachable) rubber duck antenna and belt

clip and carrying strip. It comes without batteries. Other equipment is optional.

2. SPECIFICATION

2.1 GENERAL SPECIFICATIONS

a) Frequency Range : 446.00625 ~ 446.09375 MHz

b) Output Impedance : 50Ω unbalanced

c) Modulation Type : 8K0F3E

d) Communication Mode : semi-duplex

e) Channel Capacity : 8 channels

f) Channel spacing : 12.5 kHz

g) Power : 6.0V(alkaline), 4.8 V (NiMH)

h) Battery Life : ALKALINE: at 1000mAh >30 hours (Tx5%, Rx5%, Stand-by 90%)

i) Operating Temperature : -20 degrees C to +60 degrees C

j) Dimension : 95.5(H)x 50(W)x 26(D)mm

k) Weight : 132 g (with Battery)

2.2 ELECTRICAL SPECIFICATION

a) TRANSMITTER

1) Output power : Max. 500 mW

2) Frequency Stability : ±5 ppm(-20 ~+ 60 )

3) Modulation Method : FM

4) Oscillation Method : PLL SYNTHESIZER

5) Max. Frequency Deviation : < +/- 2.5 kHz (with tone)

6) Cooling Method : air-cooling Method

7) Spurious Emission : < -36dBm /-30dBm

8) FM Hum/Noise : > -40dB (1kHz 60% modulation,w/CCITT)

9) Distortion : < 5% (1kHz 60% modulation)

10) Tx Audio Response : 6dB /OCT +/- 3dB PRE-EMPHASIS (300Hz~2.5kHz)

b) RECEIVER

1) Receive Method : Double Super Heterodyne

2) Receive Sensitivity : < 0.28uV(20dB SINAD w/CCITT)

3) Squelch Sensitivity : 6 to 8 dB at 12dB SINAD

4) Bandwidth : > 3kHz (6dB ATT point)

5) Selectivity : < -60dB (25kHz)

6) Local Frequency Stability :+/- 5 ppm( between –20 degrees C and +60 degrees C)

7) Spurious Response : > 40dB

8) Audio output : 200mW (Internal 8 Ohms load THD 10%) Ext: 100mW

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9) Distortion : < 5% (1kHz 60% Modulation)

10) RX Audio Response : 6dB/OCT +/- 3dB DE-EMPHASIS (300Hz to 2.5kHz)

11) S/N Ratio : < 40dB (1kHz 60% modulation w/CCITT)

12) IF : 1'st IF = 21.7MHz

2'nd IF = 450kHz

13) Local Frequency :

1st Local Frequency = fc - 21.7MHz

2nd Local Frequency = 21.25MHz

3. OPERATION

3.1 Push Buttons and Controls

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1) Battery Door

2) Monitor Button

3) Detachable Belt Clip

4) Push-To-Talk (PTT) Button

5) Antenna

6) External Mic / Speaker

7) Built-in Speaker

8) LCD Panel

9) Built-in Microphone

10) Up Button & Volume Control

11) Down Button & Volume Control

12) Function Button

13) Power On/Off & Enter Button

3.2 ICONS on LCD

1) RSSI (Receiving Signal Strength Indicator) or TX Bar Icon

Indicates the receiving signal strength and blinks during
transmission.

2) Monitor Indicator

Appears when the monitor button is used.

3) CTCSS Indicator

Blinks when the correct CTCSS tone is entered.

4) Auto Channel Scan Indicator

Appears in the auto scan mode or when the auto scan mode is
activated.

5) Dual Watch Scan Indicator

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Appears in dual watch scan mode or when the dual watch scan mode is
activated.

6) Key Lock Indicator

Blinks in auto lock selection mode or when the key lock is
activated.

7) VOX Indicator

Blinks in VOX selection mode or appears when VOX is activated.

8) Battery Level Indicator

Battery Level Meter indicates the remaining battery strength.

9) Power Save Display

Blinks when the power save is activated.
The rate at which the icon blinks varies with the power saving
ratio.
Fast indicates a lower power saving while slow indicates a higher
Power saving ratio.

10) Tx Indicator

Appears when a signal is being transmitted.

11) Rx Indicator

Appears when a signal is being received.

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12) Large Segment Display

Indicates the channel number in use at the normal mode.
When the Function Button is pressed, it displays the function menu

in sequence: CH / SC / dW / UO / Udt / ALo / CAL / ton

13) Small Segment Display

Displays the CTCSS tone option at the normal mode.
CTCSS option is displayed in Hz.

Displays the SUBMENU of each MENU in the function mode.
(e.g. CH 1~69 / SC: up, dn / dW: channel number /
UO: high, off,low / Udt: 5sec, 3sec, 2sec, 1sec / ALo: off, auto /

CAL number:1-7 / ton:no-Freq) 3.3 Key Function

3.3 Key Functions

3.3.1 ENTER BUTTON (#13)

1) Short Touch - Power On

Press this button (#13) briefly to turn the unit on.
A short confirming melody will play.

2) Long Touch - Power Off

Press this button (#13) for longer than 1.5 seconds to turn the unit off.
Note: Press it to confirm the required option for respective functions during

function edit mode.

3.3-2 FUNCTION BUTTON (#12)

1) Short Touch

Press this button briefly to enter function edit mode in standby mode.

2) Long Touch

Press for longer than 1.5 seconds to activate the KEY LOCK in the
standby mode.

Please note all buttons will be disabled except the Monitor Button (#2)
and PTT Button (#4) will remain fully operational.

3.3.3 UP BUTTON (#10)

1) Short Touch