TOSHIBA FT8800 Service Manual

FILE NO. 2B0-200007

SERVICE MANUAL

CORDLESS TELEPHONE

FT-8800

PUBLISHED IN JAPAN, Sep., 2000

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........................................................................... 25

ELECTRICAL PARTS LOCATION............................................................................................. 27

WIRING DIAGRAMS .................................................................................................................29

EXPLODED VIEW AND MECHANICAL PARTS LIST............................................................... 31

PARTS LIST............................................................................................................................... 35

ASSEMBLY PARTS LIST .......................................................................................................... 47

SPECIFICATIONS ..................................................................................................................... 48

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 in the schematic diagram and the parts list. Before replacing 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.

OPERATING CONTROLS

HANDSET CONTROLS AND FUNCTIONS

Antenna

LCD Display

VOL/RING Button

900

MHz

COMPANDOR NOISE REDUCTION

REDIAL FLASH

VOL/

TALK

GHI

PQ RS

TONE

MEM

RING

CID

SELECT

LOCALL.D.

DEF

ABC

TUV

OPER

MNO

JKL

DELETE

FUNC

1 4

PAUSE

REDIAL Button

TALK Button

L.D. Button

(TONE) Button

MEM (Memory) Button

PAUSE Button

FLASH Button SELECT Button

CID Button LOCAL Button

Dialpad

DELETE CH Button FUNC Button

Charging contact

BASE UNIT CONTROLS AND FUNCTIONS

PULSE/TONE Switch

DC IN 9V Jack

TEL LINE Jack

CALLER-ID

CORDLESS

TELEPHONE

FT-8800

DIGITAL

IN USE

CHARGE

Rechargeable Battery Pack(back)

Antenna

Cradle

IN USE/CHARGE LED

Charging Contact

900

COMPANDOR NOISE REDUCTION

MHz

PAGE

PAGE Button

Base Unit

ALIGNMENT PROCEDURE

Transmitter Section

Connections

Power

Meter

Frequency

Counter

Deviation

Mater

RF Test Point

BASE Unit

J2 DC IN 9V Jack

TEL Line

Jack

1kHz -15dBm

AF GEN.

Adapter

AC 120V 60Hz

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 sectonds.

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

Alignment Procedure

step

Adjustment

RT301

(TX P ower)

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 -7dBm 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 “PAGE” k e y 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 -15dBm from the AF Generator . Connect the Deviation Meter to the RF test point on the Base MAIN PCB. Adjust RT3 to indicate ±8 kHz De v.

Alignment Point Location on Base Main PCB and Base RF PCB

Base Main PCB

Base RF PCB

RT3

CT1

RT301

RF Test Point

J1 TEL LINE Jack

J2 DC IN 9V Jack

S2 TONE/PULSE Switch

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 Discr iminator test point. Adjust L3 to indicate DC 0.95 V.

Connect the AC Voltmeter across a 600-ohm dummy to the Telephone Line Jack. Adjust RT2 for a -11dBm 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

RF Test PointDiscriminator Test Point

J1 TEL LINE Jack

J2 DC IN 9V Jack

S2 TONE/PULSE Switch

Handset Unit

Transmitter Section

Connection

Power

Meter

Frequency

Counter

Deviation

Mater

RF Test Point

HANDSET Unit

J603 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 beep.

Alignment Procedure

step

Adjustment

RT501

(TX Po wer)

CT601

(TX Frequency)

Remarks

Connect the RF power Meter to the RF test point on the handset MAIN PCB. Adjust RT501 for a -5dBm reading on the Power Meter.

Connect the Frequency Counter to the RF test point on the handset MAIN PCB. Adjust CT601 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

RT603

(TX Modulation)

the MIC Connector make sure that the output is 1kHz 9mV from the AF Generator. Connect the Deviation Meter to the RF test point on the handset MAIN PCB . Adjust RT603 to indicate ±8 kHz De v.

Alignment Point Location on Handset Main PCB and Handset RF PCB

Handset PCB

RT603

J603

CT601

MC601

RF PCB

RT501

RF Test Point

Receiver Section

Connections

RF SG

DC Power Supply

J603

Battery

Connector

DC 3.8V

RF Test Point

Connector

AF Terminal

Dummy Load

(150-ohm)

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 beep.

Alignment Procedure

step

Preset to

SG: 1mV

No modulation

SG: 1mV

1 kHz ±8kHz

deviation

SG: -6.0 dB

1kHz ±8kHz

Deviation

Adjustment

L603

(Discriminator

Voltage)

RT602

(RX AF

Voltage)

µµ

µV

µµ

RT601

(SQ Point)

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 Discriminator test point. Adjust L603 to indicate DC 0.85 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 MIC Connector. Adjust RT602 for a 100 mV reading on the AC Voltmeter.

Press the “5” k e y to enter the TEST Mode 5. Mak e sure that the frequency of RF SG output is 926.997467 MHz. Adjust RT601 to turn to the point where the Ringer just beeps.

AC V oltmeterHANDSET Unit

DC V oltmeter

Remarks

Alignment Point Location on Handset Main PCB and Handset RF PCB

Handset PCB

J603

Discriminator Test Point

RT601

RT602

L603

RF PCB

RF Test Point

Base Unit

BLOCK DIAGRAMS

B301

Handset

B501

Base Unit

SCHEMATIC DIAGRAMS

B301 RF MODULE

Handset

B501 RF MODULE

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 3 of IC2?

Check IC2 and its peripheral circuit.

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

Check IC4 and TEL network circuit.

Check R58 and R59.

Deletion of the Caller ID memory

To delete the Caller ID memory in the EEPROM, proceed with the f ollo wing process:

1) Connect the battery with pressing and # buttons, and keep pressing the buttons continuously for approximate 2 seconds.

2) Release buttons when entering TEST mode with beep.

3) Press CID button.

4) A confirmation beep will sound after about 8 seconds, then the data for caller ID is deleted. (Note: Do not disconnect the battery until you hear the confirmation beep, otherwise the data may not be completely deleted.)

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 pin32 of IC2 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 Q616 collector, can the pulse wave be seen?

Check RINGER Y601.

Check R55, R77 and S1.

Check IC603.

Check R688, R673, R689, R672, R629, Q616 and Q617.

Check IC4 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 FREQ UENCY on the base unit.

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

Press “PAGE” key 7 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 IC4 and its

peripheral circuit.

Check base RF unit.

NG Check whether there is a

250 Hz data wavef orm at C80.

Check base RF unit.

NG Check whether there is a

250 Hz data wavef orm at pin 9 of IC3.

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

Check RT3, R53, R70,

R68, R69, R28, C35, C80 and C89.

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 FREQ UENCY on the handset unit.

Check whether there is a 250 Hz data wavef orm at pin 23 of IC2.

Check IC2 and its peripheral circuit.

Check IC603 and its

peripheral circuit.

Check handset RF unit.

Check IC1 and their

peripheral circuit.

Press “3” key, check whether deviation of the TX data is app. 8 kHz Dev.

Press “6” key,

926.997467 MHz (250 Hz ±8 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.

NG Check whether there is a

250 Hz data wavef orm at C669.

Check handset RF unit.

Check whether the 250

Hz data waveform from pin 9 of IC606 is fed.

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

Check whether there is a 250 Hz data wav eform at pin 55 of IC603.

Check R635, R636,

R634, R632, R619, C610, C669 and RT603.

Check handset RF unit

and the peripheral circuit of IC606.

Check RT602, Q601 and

their peripheral circuit.

Check IC601 and their

peripheral circuit.

Check IC603 and its peripheral circuit.

+ 35 hidden pages

TOSHIBA FT8800 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

CONTENTS

SAFETY PRECAUTIONS

OPERATING CONTROLS

ALIGNMENT PROCEDURE

BLOCK DIAGRAMS

SCHEMATIC DIAGRAMS

TROUBLESHOOTING HINTS