TOSHIBA FT-7800 Service Manual

Teléfonos

Precauciones de seguridad Controles de operación

FT-7800

Procedimiento de ajuste Diagramas a bloques Diagramas esquemáticos Consejos para localización de fallas Tablas de voltajes en transistores e ICs Identificación de terminales en semiconductores Localización de partes eléctricas Diagramas de alambrado Vistas explotadas y lista de partes eléctricas Lista de partes Lista de partes para ensamblado Especificaciones

FILE NO. 2B0-200001

SERVICE MANUAL

CORDLESS TELEPHONE

FT-7800

PUBLISHED IN JAPAN, June., 2000

CONTENTS

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

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

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

BLOCK DIAGRAMS..................................................................................................................... 7

SCHEMATIC DIAGRAMS............................................................................................................9

TROUBLESHOOTING HINTS ...................................................................................................13

IC AND TRANSISTOR VOLTAGE CHART ............................................................................... 20

SEMICONDUCTOR LEAD IDENTIFICATION........................................................................... 24

ELECTRICAL PARTS LOCATION............................................................................................. 26

WIRING DIAGRAMS .................................................................................................................28

EXPLODED VIEW AND MECHANICAL PARTS LIST............................................................... 30

PARTS LIST............................................................................................................................... 34

ASSEMBLY PARTS LIST .......................................................................................................... 43

SPECIFICATIONS ..................................................................................................................... 44

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 manufacture 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 indentified 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

OPERATING CONTROLS

HANDSET CONTROLS AND FUNCTIONS

Speaker

TALK/BATT.LOW LED

MEM button TALK button

TALK

BATT LOW

TALK FLASH

MEM

abc def

123

TONE button

REDIAL button

PAUSE button

Rechargeable Battery Pack

(back)

456 789

TONE

REDIAL

PAUSE CH VOL/RING

MEM1 MEM2 MEM3

mno

jklgfi

tuvpqrs

wxyz

oper

Antenna

FLASH button

Dialpad

CH button

VOL/RING button

One-touch dialing button ( MEM1 - MEM3 )

BASE UNIT CONTROLS AND FUNCTIONS

DC In 9V Jack

TEL LINE Jack

IN USE

CHARGE

PAGE

Charging Contacts

T-P (TONE-PULSE) Switch

Hook

IN USE/CHARGE LED

PAGE button

Charging Contacts

ALIGNMENT PROCEDURE

Base Unit

Transmitter Section

Connections

Power

Meter

Frequency

Counter

Deviation

Mater

RF Test Point

Preset

a) Connect the base RF unit to the base main unit. b) Set the “T ONE / PULSE” switch to PULSE. c) Connect the AC adapter to the base unit while pressing the “PAGE” key, and keep pressing it continuously for

approximate 2 sectonds.

d) Release the “PAGE” key when entering TEST mode 1 with IN USE LED lighting.

BASE Unit

J2 DC IN 9V Jack

TEL Line

Jack

1kHz 77.5mV

AF GEN.

Adapter

AC 120V 60Hz

Alignment Procedure

step

Adjustment

RT301

(TX Po wer)

CT1

(TX Frequency)

RT3

(TX Modulation)

Remarks

Connect the Po w er Meter to the RF test point on the Base MAIN PCB. Adjust RT301 for a -7.5dBm reading on the Power Meter.

Connect the Frequency Counter to the RF test point on the Base MAIN PCB. Adjust CT1 to make sure that the frequency is 926.897468 MHz.

Press the “PA GE” k ey to enter the TEST Mode 2. Connect the AF Generator to the TEL Line J a ck on the Base Main PCB. Make sure that the output is 1 kHz 77.5 mV from the AF Generator . Connect the Deviation Meter to the RF test point on the Base MAIN PCB . Adjust RT3 to indicate ±8 kHz Dev.

Alignment Point Location on Base Main PCB and Base RF PCB

Base Main PCB

RT3

Base RF PCB

RT301

CT1

J1 TEL LINE Jack

J2 DC IN 9V Jack

S2 T/P Switch

RF Test Point

Receiver Section

Connections

RF SG

RF Test Point

TEL Line

Jack

Dummy Load

(600-ohm)

AC V oltmeterBASE Unit

AC 120V

60Hz

Adapter

DC IN 9V Jack

AF Terminal

DC V oltmeter

Preset

a) Connect the base RF unit to the base main unit. b) Set the “TONE/PULSE” switch to PULSE. c) Connect the AC adapter to the base unit while pressing the “PAGE” key, and keep pressing it continuously for

approximate 2 seconds.

d) Release the “PAGE” key when entering TEST mode 1 with IN USE LED lighting.

Alignment Procedure

step

Preset to

SG: 1mV

No modulation

SG: 1mV

1 kHz ±8kHz

deviation

SG: -6.0 dB

1kHz ±8kHz

Deviation

Adjustment

(Discriminator

Voltage)

(RX AF

Voltage)

µµ

µV

µµ

(SQ Point)

RT2

RT1

Remarks

Press the “PAGE” key for 3 times to enter the TEST Mode 4. Connect the RF Signal Generator to the RF test point on the Base MAIN PCB. Make sure that the frequency is 902.952467 MHz. Connect the DC Voltmeter to the AF test point. Adjust L3 to indicate DC

1.00 V. Connect the AC Voltmeter across a 600-ohm dummy to the Telephone Line

Jack. Adjust RT2 for a 220 mV reading on the AC voltmeter. Press the “PAGE” key to enter the TEST Mode 5. Make sure that the

frequency of RF SG output is 902.952467 MHz. Adjust RT1 to turn to the point where the CHG LED just turns on.

Alignment Point Location on Base Main PCB and Base RF PCB

Base Main PCB

RT2

RT1

AF Test Point

J1 TEL LINE Jack

J2 DC IN 9V Jack

S2 T/P Switch

RF Test Point

Handset Unit

Transmitter Section

Connection

Power

Meter

Frequency

Counter

Deviation

Mater

RF Test Point

HANDSET Unit

J401 Battery Connector

MIC+Pin

AF GEN.

1kHz 9mV

DC Power Supply

DC 3.8V

Preset

a) Connect the handseet RF unit to the handset main unit. b) Connect DC power supply to battery connector on the handset unit. c) Turn the DC power supply On while pressing " ∗ " and " # " keys, and keep pressing the keys continuously for

approximate 2 seconds.

d) Release keys when entering TEST mode 1 with TALK LED lighting and beep.

Alignment Procedure

step

Adjustment

RT501

(TX Po wer)

CT401

(TX Frequency)

Remarks

Connect the RF power Meter to the RF test point on the handset MAIN PCB. Adjust RT501 for a -7.5dBm reading on the Power Meter.

Connect the Frequency Counter to the RF test point on the handset MAIN PCB. Adjust CT401 to make sure that the frequency is 903.052467 MHz.

Press the “2” key to enter the TEST Mode 2. Connect the AF Generator to

RT403

(TX Modulation)

the MIC Connector. Make sure that the output is 1kHz 8mV from the AF Generator. Connect the Deviation Meter to the RF test point on the handset MAIN PCB. Adjust RT403 to indicate ±8 kHz De v.

Alignment Point Location on Handset Main PCB and Handset RF PCB

Handset PCB

MC601

J401

RT403

CT401

RF PCB

RT501

RF Test Point

Receiver Section

Connections

RF SG

Test PointSPTerminal

Dummy Load

(150-ohm)

WHT BLK

AC V oltmeterHANDSET Unit

DC Power Supply

J401

Battery

Connector

DC 3.8V

AF Test Point

DC V oltmeter

Preset

a) Connect the handset RF unit to the handset main unit. b) Connect DC power supply to battery connector on the handset unit. c) Turn the DC power supply ON while pressing “

” and “ # ” keys, and keep pressing the keys continuously for

approximate 2 seconds.

d) Release keys when entering TEST mode 1 with TALK LED lighting and beep.

Alignment Procedure

step

Preset to

SG: 1mV

No modulation

SG: 1mV

1 kHz ±8kHz

deviation

SG: -6.0 dBµV

1kHz ±8kHz

Deviation

Adjustment

L402

(Discriminator

Voltage)

RT402

(RX AF

Voltage)

RT401

(SQ Point)

Remarks

Press the “4” key to enter the TEST Mode 4. Connect the RF Singal Generator to the RF test point on the handset MAIN PCB. Make sure that the frequency is 926.997467 MHz. Connect the DC Voltmeter to the AF test point. Adjust L402 to indicate DC 1.00 V.

Connect the RF Signal Generator to the RF test point on the handset MAIN PCB. Make sure that the frequency is 926.997467 MHz. Connect the AC Voltmeter across a 150-ohm dummy to the SP Terminal. Adjust RT402 for a 130 mV reading on the AC Voltmeter.

Press the “5” k e y to enter the TEST Mode 5. Make sure that the frequency of RF SG output is 926.997467 MHz. Adjust RT401 to turn to the point where the indication is just vibrated.

Alignment Point Location on Handset Main PCB and Handset RF PCB

Handset PCB

J401

RT402

AF Test Point

L402

RF PCB

RT403

RT401

RF Test Point

WHT

BLK

SP Terminal

Base Unit

BLOCK DIAGRAMS

Handset

Base Unit

SCHEMATIC DIAGRAMS

Handset

TROUBLESHOOTING HINTS

1. The bell does not ring.

When the PAGE SW 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 IC4?

Is there pulse wave at pin 21 of IC5?

Check IC5 and its peripheral circuit.

BASE UNIT

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

Check IC4 and TEL network circuit.

Check R58, C45 and R59.

If you want to reset the unit to the factory settings

1) Set the T/P s witch to TONE position.

2) Diconnect the AC adaptor and telephone line code from the base.

3) While pressing the “PAGE” key, plug the AC adaptor. Keep pressing the “PAGE” key for about 3 seconds.

4) Keep pressing the “PAGE” k ey, then the IN USE LED will light and the base unit will be reset.

HANDSET

Delection of the Caller ID memory

To delete the Caller ID memory in the EEPROM, proceed with the folloing process:

1) Diconnect the battery from the connector.

2) Connect the battery with pressing and # buttons, and keep pressing the buttons continuously for about

3 seconds.

3) Keep pressing the buttones, and a beep tone will sound and TALK LED will light.

4) Press the “MEM” key, then the handset unit will be reset.

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

Can the base and handset be connected?

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

When the PAGE SW of the base is pressed, does pin20 of IC5 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 38 of IC404 be seen?

At the Q408 collector, can the pulse wave be seen?

Check RINGER Y401.

Check R55, R77 and S1.

Check IC404.

Check R454, R457 and D402.

Check IC5 and its peripheral circuit.

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.

Press the “PAGE” key 2 times, check whether deviation of the TX data is app. 8 kHz Dev.

Press the “PAGE” key 5 times, 902.952467 MHz (250 Hz ±8 kHz Dev.) 1mV output signal from RF jack is applied. Can the IN USE LED be lighted?

NGACheck IC5 and its

peripheral circuit.

Check base RF unit.

Check whether there is a

250 Hz data wav eform at “MOD” of RF unit.

Check base RF unit.

NG Check whether there is a

250 Hz data wav eform at pin 9 of IC3.

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

Check RT3, R40, R68,

R69, R53, R70 and C79.

Check base RF unit and

the peripheral circuit of IC3.

Check RT2, Q2 and their

peripheral circuit.

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 wav eform at pin 38 of IC5.

Check IC5 and its peripheral circuit.

NG Check IC404 and its

peripheral circuit.

Check handset RF unit.

Check R42, R46, IC1 and

their peripheral circuit.

+ 32 hidden pages