Toshiba FT 8258 Service Manual

FILE NO. 2B0-9801

SERVICE MANUAL

CORDLESS TELEPHONE

FT-8258

PUBLISHED IN JAPAN, Jun., 1998

CONTENTS

SAFETY PRECAUTIONS ......................................................................................................................1

OPERATING CONTROLS.....................................................................................................................2

ALIGNMENT PROCEDURE..................................................................................................................3

BLOCK DIAGRAMS...............................................................................................................................9

SCHEMATIC DIAGRAMS....................................................................................................................14

TROUBLESHOOTING HINTS.............................................................................................................24

IC AND TRANSISTOR VOLTAGE CHART ......................................................................................... 31

SEMICONDUCTOR LEAD IDENTIFICATION.....................................................................................38

ELECTRICAL PARTS LOCATION ......................................................................................................42

WIRING DIAGRAMS ...........................................................................................................................47

EXPLODED VIEW AND MECHANICAL PARTS LIST ........................................................................49

PARTS LIST ........................................................................................................................................53

ASSEMBLY PARTS LIST ....................................................................................................................75

SPECIFICATIONS ...............................................................................................................................76

SAFETY PRECAUTIONS

Before returning any models to the customer, a safety check of the entire instrument should be made. The service technician must be sure that no protective device built into the instrument by the manufacturer has become defective or inadvertently degraded during servicing.

1. WARNING:

Alterations of the design or circuitry of these models should not be made. Any design changes or additions such as, but not limited to, circuit modifications, auxiliary speaker

jacks, switches, grounding, active or passive circuitry, etc. may alter the safety characteristics of these models and potentially create a hazardous situation for the user.

Any design alterations or additions will void the manufacturer’s warranty and will further relieve the manufacturer of responsibility for personal injury or property damage resulting therefrom.

2. PRODUCT SAFETY NOTICE

Many electrical and mechanical parts in this chassis have special characteristics. These characteristics often pass unnoticed and the protection afforded by them cannot necessarily be obtained by using replacement components rated for higher voltage, wattage, etc. Replacement parts that have these special safety characteristics are identified in this manual and its supplements; electrical components

having such features are identified by a any of these components, read the parts list in this manual carefully. The use of substitute replacement parts that do not have the same safety characteristics as specified in the parts list may create shock, fire or other hazards.

in the schematic diagram and the parts list. Before replacing

— 1 —

HANDSET CONTROLS

OPERATING CONTROLS

LINE 1 LED (Green)

• Lights when the handset is used for a phone conversation on line 1.

• Blinks when the base unit or additional phone is in use on line 1.

• Blinks when line 1 is put on hold.

• Blinks when line 1 is ringing.

TALK/BATT LOW LED (Red)

Standby status : OFF

•

Lights ON during a phone

conversation using the handset.

•

Blinks when a channel is changed, and during the low battery status and mute status.

TALK button TONE button

FLASH/RDL (Flash/Redial) button

MEM (Memory) button INTCOM button

PAUSE button

TALK

ABC DEF

123

JKL MNOGHI

456

PQ RS

TONE

FLASH/RDL INTCOM CH

MEM

TUV

789

OPER

VOL/RING

PAUSE

PRIVACY

Charging Contacts

Battery compartment (back)

Antenna LINE 2 LED (Orange)

•

Lights when the handset is used for

a phone conversation on line 2.

•

Blinks when the base unit or

additional phone is in use on line 2.

•

Blinks when line 2 is put on hold.

•

Blinks when line 2 is ringing.

LINE 1 button LINE 2 button

SPEED DIAL INDEX (back) Dialpad (1~9, and # Dial Buttons)

VOL/RING (Volume/Ringer volume) button

HOLD button

CH (Channel) button

CONF (Conference) button

BASE UNIT CONTROLS

DC IN 9V jack

TEL LINE 2 jack

TEL LINE 1/2 jack

Dialpad (1~9, and #

Dial Buttons)

TONE button

FLASH/RDL (Flash/Redial) button

LINE 2 LED (Orange)

Lights when the base unit is used

•

for a phone conversation on line 2.

• Blinks when the handset or additional phone is in use on line 2.

• Blinks when line 2 is put on hold.

• Blinks when line 2 is ringing.

LINE 1 LED (Green)

•

Lights when the base unit is used

as speaker phone on line 1.

• Blinks when the handset or additional phone is in use on line 1.

• Blinks when line 1 is put on hold.

• Blinks when line 1 is ringing.

LINE 2 button LINE 1 button

CHARGE LED

POWER LED

ABC DEF

12 3

JKL MNOGHI

45 6

TUV

789

RS YZ

TONE

OPER

FLASH/RDL

MHZ

900

CHARGE POWER

Microphone

Tone/Pulse switch Line 1 ringer

volume switch

Line 2 ringer volume switch

Speaker

One-touch dialing keys (1 to 8)

Antenna

MEM (Memory) button

PAUSE button

MEM

PRIVACY PAUSE

MUTE

INTCOM

SPEAKER

MUTE button

INTCOM LED (Green)

SPEED DIAL INDEX

• Pull out the SPEED DIAL INDEX card to find out a destination name associated with a number preset in the speed dial memory.

INTCOM button HOLD button CONF (Conference)

button SPEAKER LED (Green) SPEAKER volume control

SPEAKER button

— 2 —

ALIGNMENT PROCEDURE

Test Mode For Base Unit

Press the “ ” and “#” keys at the same time about 1.5 seconds while turning the power on, the confirmation beep will sound to indicate that the unit is in the test mode.

1. To change the TEST mode: Press the number key for the corresponding TEST mode. (Refer to the following table)

2. To change channel: Press the “FLASH/RDL” key, but if changing the step, the channel returns to the start channel.

3. To cancel Test mode: Bell rings, charge the Handset, or press the “SPEAKER” key.

S T E P

1VCO/TX FRQ. ADJ 1 19LLL LLLLLLLLLLLLHHH

3TX DATA 3 19LLLLLLLLLLLLLLLHHH*2

5SQ SENS 5 19LLH/LHLHLLLLLLLLLHHH*3 6BELL MODULATION 6 19LHLHLHLLLLLLLLLHHH 7RINGER CHECK 7 19HLL LLLLLLLLLLLLHHH*4 8DATA IN CHECK 8 19LLHHLHLLLLLLLLLHHH*5 9CHANNEL DATA 9 19HLLLLLLLLLLLLLLHHH*6

11 12INTERCOM HOLD19LHH/LLLLLLLHLLLLLLLL *8

13ON HOOK PARA INT’C19HHL LLLLLLLLLLLLHHH *9

FUNCTION

TX CHECK L1 LHLHLHLLLLLLLLLHHH TX CHECK L2 L H L L H L H L L L L L L L L H H H2 TX CHECK L1 + L2

RX SENS L1 HLHHLHLLLLLLLLLHHH RX SENS L2 H L H L H L H L L L L L L L L H H H4 RX SENS L1 + L2

DUPLEX L1 LHHHLHLLLLLLLLLHHH DUPLEX L2 LHHLHLHLLLLLLLLHHH10 DUPLEX L1 + L2 DUAL TONE L1 H L L H L L L L L L L H L L H H H H*1 DUAL TONE L2

219

419

019

MEM 19

C H

LHLHHHHLLLHLLLLHHH

HLHHHHHLLLHLLLLHHH

LHHHHHHLLLHLLLLHHH

HLLLHLLLLLLLHLHHHH *7

M P

*1 : Switch the line with LINE1, LINE2, and CONF keys, the corresponding LED lights. *2 : “0000...” (250Hz) will be fed out continuously as transmitting data. *3 : INTCOM LED lights when sensing SQ. *4 : INTCOM LED lights when detecting BELL. *5 : INTCOM LED lights when the received data are “0000...” (250Hz).

(In the case of Dual Tone, changes as 1→ 2 → 3 → 4 →5 → 6 →7 → 8 → 9 → 0 → * → # → 1.) *6 : Charge LED lights when detecting Charge ON. *7 : Every pushing of PAUSE key makes tone change.

DTMF Frequency

ROW1 : 697 ROW2 : 770 ROW3 : 852 ROW4 : 941 COL1 : 1209 COL2 : 1336

COL3 : 1477 *8 : RX Mute turns on or off when pushing MUTE key. (Off initially, on when pushed.) *9 : LINE LED lights as follows according to the condition of the telephone used together.

ON Hook : ON OFF Hook : Blinking No Connection : OFF

Channel rotation

19 → 20 → 21 → 40 → 1 → 2 → 3 → 4 → 5 . . . . . . . . 37 → 38 → 39 → 40

↑

— 3 —

Test Mode For Handset Unit

To perform the TEST mode, turn the power ON by pressing the “ ” and “#” buttons at the same time. When entered the TEST mode, the bell rings and the unit enters TEST mode 1 . ( Refer to the following table. )

1. To change the TEST mode: Press the number key for the corresponding TEST mode.

(Refer to the following table)

2. To change channel: Press “CH” key.

( Note: If the step is changed, the channel returns to the start channel. )

3. To cancel the TEST mode: Turn the power OFF, charge the Handset, or press the “TALK” key.

STEP FUNCTION KEY START CH TX PWR RX PWR TX MUTE RX MUTE CONV REMARKS

1 VCO/TX FREQ. ADJ 1 21 L H H L H 2 TX MOD. CHECK 2 21 L H L L L 3TX DATA 3 21 L H L L L 4RX SENS 421HHLHL 5SQ SENS 5 21 L H L *A L 6 RECEIVE DATA CHECK 6 21 L H L L H 7 BELL 7 21 H L L L H 8 BATTERY LOW CHECK 8 21 H L L L H 9 CHARGE CHECK 9 21 H L L L H

10 DUPLEX 0 21 L H H H L

*A : Squelch ON is H, or Squelch OFF is L. *1 : In the TEST mode 3, “0000...” will be fed out continuously as transmitting data. *2 : In the TEST mode 6, bell (1kHz) rings when the data received is “0000...”. *3 : In the TEST mode 7, bell rings with initial 2 tone (2kHz, 2.2kHz). *4 : In the TEST mode 8, bell (1kHz) rings when P_BATLOW is “L”. *5 : In the TEST mode 9, bell rings when P_CHRGIN is “L”.

Channel rotation

21 → 20 → 19 → 40 → 1 → 2 → 3 → 4 → 5 . . . . . . . . 37 → 38 → 39 → 40

↑

— 4 —

Base Unit

Transmitter Section

Connection

Power

Meter

Frequency

Counter

Deviation

Meter

RF Test Point

BASE RF PCB

RF Test Point

BASE MAIN PCB

DC IN

9V Jack

TEL Line

1/2 Jack

AF GEN.

1kHz 61.0mV

Adapter

Preset

Place the Base Unit in VCO/TX FREQ ADJ mode in accordance with the procedure on page 3.

Alignment Procedure

Step Adjustment Remarks

VR202

(TX Power)

CT201

(TX Frequency)

RT2

(TX Modulation)

Connect the Power Meter to the RF test point on the Base RF PCB. Adjust VR202 for a

−

4 dBm reading o n the Power Meter.

Connect the Frequency Counter to the RF test point on the Base RF PCB. Adjust CT201 to make sure that the frequency is 926.900494 MHz.

Press the “2” key to enter the TEST Mode 2. Connect the AF Generator to the TEL Line Jack on the Base Main PCB. Make sure that the output is 1 kHz 61.0 mV from the AF Generator. Connect the Deviation Meter to the RF test point on the Base RF PCB. Adjust RT2 to indicate

8 kHz Dev.

AC 120 60Hz

Alignment Point Location on Base Main PCB and Base RF PCB

Base Main PCB

RT2

Base RF PCB

J201

CT201

VR202

— 5 —

J5 TEL LINE 1/2 Jack

J2 DC IN 9V Jack

RF TEST POINT

Receiver Section

Connection

RF SG

AC 120V

60Hz

BASE RF PCB

−

Test Point

Adapter

BASE MAIN PCB

DC IN

9V Jack

TEL Line 1/2 Jack

− +

J1 AF Term i n a l

Dummy Load

(600-ohm)

DC Voltmeter

AC Voltmeter

Preset

Place the Base Unit in RX SENS mode (step 4) in accordance with the procedure on page 3.

Alignment Procedure

Step Preset to Adjustment Remarks

Connect the RF Signal Generator to the RF test point on the Base RF PCB. Make sure that the frequency is 902.979122 MHz. Connect the DC Voltmeter to the J1 AF test point. Adjust L212 to indicate DC 0.95 V.

Connect the RF Signal Generator to the RF test point on the Base RF PCB. Make sure that the frequency is 902.979122 MHz. Connect the AC Voltmeter across a 600-ohm dummy to the Telephone Line Jack. Adjust R T1 for a 218 mV reading on the AC voltmeter.

Press the “5” key to enter the TEST Mode 5. Make sure that the frequency of RF SG output is 902.979122 MHz. Adjust VR201 to turn to the point where the INTCOM LED just turns on.

SG: 1mV

No modulation

SG: 1 mV

1 kHz ±8kHz

deviation

SG:

No modulation

−7

dBµV

L212

(Discriminator

Voltage)

RT1

(RX AF

Voltage)

VR201

(SQ Point)

Alignment Point Location on Base Main PCB and Base RF PCB

Base Main PCB

Base RF PCB

RT1

AF TEST POINT

L212

VR201

— 6 —

J201

J5 TEL LINE 1/2 Jack

J2 DC IN 9V Jack

RF TEST POINT

Handset Unit

Transmitter Section

Connection

Power

Meter

Frequency

Counter

Deviation

Meter

RF Test Point

HANDSET RF PCB

RF Test Point

HANDSET MAIN PCB

Battery

Terminals

MIC + Pin

AF GEN.

1kHz 11.0mV

DC Power Supply

DC 3.8V

Preset

Place the Handset in VCO/TX FREQ. ADJ mode in accordance with the procedure on page 4.

Alignment Procedure

Step Adjustment Remarks

VR502

(TX Power)

CT501

(TX Frequency)

VR601

(TX Modulation)

Connect the RF power Meter to the RF test point on the handset RF PCB. Adjust VR502 for a −6 dBm reading on the Power Meter.

Connect the Frequency Counter to the RF test point on the handset RF PCB. Adjust CT 501 to make sure that the frequency is 903.079230 M Hz.

Press the “2” key to enter the TEST Mode 2. Connect the AF Generator to the MIC Connector. Make sure th at the ou tput is 1 kHz 11.0 mV from the AF Generator. Connect the Deviation Meter to the RF test point on the handset RF PCB. Adjust VR601 to indicate ± 8kHz Dev.

Alignment Point Location on Handset Main PCB and Handset RF PCB

Handset Main PCB RF PCB

MIC + Pin

MC601

−

Battery Terminals

VR601

CT501

— 7 —

RF TEST POINT

J501

VR502

Receiver Section

Connection

RF SG

HANDSET RF PCB

−

Test Point

DC Power Supply

HANDSET MAIN PCB

DC 3.8V

Battery

Terminals

J602

Connector

J601 AF Terminal

− +

Dummy Load

(150-ohm)

DC Voltmeter

AC Voltmeter

Preset

Place the Handset in RX SENS mode (step 4) in accordance with the procedure on page 4.

Alignment Procedure

Step Preset to Adjustment Remarks

Connect the RF Signal Generator to the RF test point on the handset RF PCB. Make sure that the frequency is 927.000602 MHz. Connect the DC Voltmeter to the J601 AF test point. Adjust L512 to indicate DC 0.95 V.

Connect the RF Signal Generator to the RF test point on the handset RF PCB. Make sure that the frequency is 927.000602 MHz. Connect the AC Voltmeter across a 150-ohm dummy to the SP Connector. Adjust VR602 for a 60 mV reading on the AC Voltmeter.

Press the “5” key to enter the TEST Mode 5. Make sure that the frequency of RF SG output is 927.000602 MHz. Adjust VR501 to turn to the point where the LINE 1 LED just turns on.

SG: 1 mV

No modulation

SG: 1 mV

1 kHz ±8 kHz

deviation

SG:

1 kHz ±8 kHz

deviation

−7 dBµV

L512

(Discriminator

Voltage)

VR602

(RX AF

Output)

VR501

(SQ Point)

Alignment Point Location on Handset Main PCB and Handset RF PCB

Handset Main PCB

−

Battery Terminals

AF TEST POINT

RF PCB

J601

VR602

L512

VR501

— 8 —

RF TEST POINT

J501

J602 SP Connector

Handset, Main

BLOCK DIAGRAMS

—9 —

Handset, RF

— 10 —

Base, RF

— 11 —

—13—

Base, Main

—12 —

SCHEMATIC DIAGRAMS

— 15 —

— 14 —

— 17 —

Base, RF

— 16 —

—19—

Base, Key

—18 —

— 21 —

Handset, Main

— 20 —

— 23 —

Handset, RF

— 22 —

TROUBLESHOOTING HINTS

1. The bell does not ring.

When the INTCOM key of the base is pressed, does the ringer on the handset ring?

When the TEL SG is joined with the base to make bell signal, is there pulse wave at Pin 4 of IC3 (Line 1) or IC12 (Line 2)?

Is there pulse wave at Pin 62 (Line 1) or 55 (Line 2) of IC18?

Check IC18 and its peripheral circuit.

See 2. The bell does not ring & page does not ring.

Check IC3 (Line 1) or IC12 (Line 2) and TEL network circuit.

Check R42, R80, R399 and C51 (Line 1) or R122, R152, R396 and C88 (Line 2).

— 24 —

2. The bell does not ring & page does not ring.

Can the base and handset be connec ted?

Press handset DIAL key while in TALK MODE. Can key touch sound be heard from the ringer?

When the INTCOM key of the base is pr essed, does Pin 8 of J1 change from high to low?

See 3. The base and handset cannot be connected.

When the key of the handset is pressed, can the pulse output at pin 58 of IC603 be seen?

At the Q606 collector, can the pulse wave be seen?

Check RINGER Y601.

Check KEY RUBBER.

Check IC603.

Check R627, R629, Q605 and Q606.

Check IC18 and its peripheral circuit.

— 25 —

3. The base and handset cannot be connected.

Check whether the base is able to set in the test mode 1.

Check the TX POWER and the TX FREQUENCY on the base unit.

Set the base in the test mode 3, check whether deviation of the TX data is app. 7 kHz Dev.

Set the base in the test mode 8, 902.979122 MHz (250 Hz ±7 kHz Dev.) 1 mV output sig nal from RF jack is applied. Can the INTCOM LED be lighted?

Check IC18 and its peripheral circuit.

Check base RF unit.

Check whether there is a 250 Hz data waveform at Pin 9 of J1.

Check base RF unit.

Check whether there is a 250 Hz data waveform at Pin 1 of J1.

Check whether there is a 250 Hz data waveform at the Q2 collector.

Check RT2, R22, R56, R57 R58, R59 and C18.

Check base RF unit.

Check RT1, Q2 and their peripheral circuits.

Check whether the handset is able to set in the test mode 1.

Check the TX POWER and the TX FREQUENCY on the handset unit.

Check whether there is a 250 Hz data waveform at Pin 11 of IC18.

Check IC18 and its peripheral circuit.

Check IC603 and its peripheral circuit.

Check handset RF unit.

Check Q5, Q6 and their peripheral circuits.

— 26 —

Set the handset in the test mode 3, check whether deviation of the TX data is app. 7 kHz Dev.

Check whether there is a 250Hz data waveform at Pin 9 of J601.

Check handset RF unit.

Check VR601, R619, R632, R634, R635, R636 and C611.

Set the handset in the test mode 6, 927.000602 MHz (250 Hz ±7 kHz Dev.) 1mV output signal from RF jack is applied. Check whether the bell ring.

Place the handset on the base to charge about 5 seconds, then connect again.

Check whether the 250 Hz data wareform from Pin 1 of J601 is fed.

Check whether there is a 250 Hz data waveform at the Q601 collector.

Check whether there is a 250 Hz data waveform at Pin 55 of IC603.

Check IC603 and its peripheral circuit.

Check handset RF unit.

Check VR602, Q601 and their peripheral circuits .

Check Q602, Q604 and their peripheral circuits .

— 27 —

4. Will not dial out.

(TONE)

Check whether th ere is a DTMF waveform on Pin 8 (Line 1) or Pin 4 (Line 2) of IC6.

Check whether th ere is a DTMF waveform on Pin 7 of IC2 (Line 1) or Pin 1 of IC11 (Line 2).

(PULSE)

Check whether th ere is a pulse on Pin 70 (Line 1) or Pin 69 (Line 2) of IC18.

Check the collector of Q8 (Line 1) or Q11 (Line 2).

Check IC10 and IC6.

Check IC2 or IC11.

Check IC18.

Check Q8 and R82 (Line 1) or Q11 and R150 (Line 2).

Check RL1 (Line 1) or RL2 (Line 2).

— 28 —

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