Toshiba FT 8808 Service Manual

FILE NO. 2B0-9810

SERVICE MANUAL

CORDLESS TELEPHONE

FT-8808

PUBLISHED IN JAPAN, Oct., 1998

CONTENTS

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

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

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

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

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

TROUBLESHOOTING HINTS.............................................................................................................26

IC AND TRANSISTOR VOLTAGE CHART ......................................................................................... 33

SEMICONDUCTOR LEAD IDENTIFICATION.....................................................................................41

ELECTRICAL PARTS LOCATION ......................................................................................................47

WIRING DIAGRAMS ...........................................................................................................................53

EXPLODED VIEW AND MECHANICAL PARTS LIST ........................................................................55

PARTS LIST ........................................................................................................................................59

ASSEMBLY PARTS LIST ....................................................................................................................83

SPECIFICATIONS ...............................................................................................................................84

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 ‚ 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.

— 1 —

OPERATING CONTROLS

ging

HANDSET CONTROLS

Antenna

Liquid Crystal Display (LCD)

TALK button

0-9, , Dial buttons

TONE button

PAUSE button

MEM (Memory)button

FUNC (Function) button Press to enter the Function Mode to perform various settings. Each time

FUNC

the button is pressed, the menu changes in the following order: DIAL MEMORY AREA CODE CIDCW ON/OFF AUTO TALK ON/OFF.

DELETE button

CANCEL button

BASE UNIT CONTROLS

Char

contacts

RDL (Redial) button CID (Caller ID) button

Press to enter the caller ID mode.

Number 1 button

Used for long distance dialing.

Number 8 ( ) button (time button)

Used to display the date and time of the received calls.

Number 9 ( ) button

Used to display the number of calls attempted by a caller

( ) button (up arrow button)

Used to scroll up the display screen.

( ) button (down arrow button)

Used to scroll down the display screen.

VOL/RING button CH (Channel) button FLASH button

Battery compartment

Cradle

PAGE

IN USE

CHARGE

POWER

LINE modular jack DC IN 9V jack Tone/Pulse switch

Base antenna

IN USE LED CHARGE LED POWER LED

PAGE button

Dot matrix display

Twelve digits by two lines dot matrix LCD. Shows the time, caller ID, memory location, instructions, error messages, and other information.

The back light of the LCD operates in the following manner: Turns on during an incoming call when the ringer is OFF. Turns on for 5 seconds and then off

-when a button is pressed (except in battery low status).

-when the phone rings and the handset is lifted from its cradle on the base unit to answer a call.

talk call id mem

talk icon

Blinks

-while the handset is connecting to the base unit.

-when a channel is being changed. Displayed during a call in progress

on the handset.

call id icon

Blinks when the handset is

connecting to the base unit. Displayed during the caller ID

review mode.

Battery icon

Displayed while the handset is being charged.

Displayed while the handset is being charged during the battery low stat us.

Blinks when the battery low s tatus occurs during standby and phone conversation.

mem icon

Displayed

-while data is being stored in and deleted from memory.

-while the Function Mode is in use.

— 2 —

ALIGNMENT PROCEDURE

Test Mode For Base Unit

To change the unit to TEST mode, set the TONE/PULSE switch to PULSE position and press the PAGE key continuously for 2 seconds while resetting by turning the power on. When entered the TEST mode, the CHARGE LED turns off, the IN USE LED will light and the unit enters TEST mode 1.

1. Rotation: Press PAGE key when the “TONE/PULSE” switch is set to Pulse.

2. To change channel: Press PAGE key when the “TONE/PULSE” switch is set to Tone. ( Note: The channel returns to the start channel when changing the step.)

3. To cancel TEST mode: BELL IN, CHG ON, POWER OFF

Note: CHARGE LED lights for about 50 msec when changing the step and channel each time by pressing the

PAGE key.

STEP FUNCTION START CH TX PWR TX MUTE RX MUTE RL CNT REMARKS

1 VCO/TX FREQ. ADJ 19 L L L L 2 TX MOD. CHEC K 19 L H L H 3TX DATA 19 L L L L 4 RX SENS 19 H L H H 5 SQ SENS 19 L L *A H 6 SINGLE TONE 19 H L L H 7 DUAL TONE 19 H L L H 8 DATA IN CHECK 19 L L L L 9 CHARGE CHECK 19 H L L L

10 DUPLEX 19 L H H H

*A : Squelch ON: H (CHARGE LED ON) Squelch OFF: L (CHARGE LED OFF) *1 : In TEST mode 3, “0000...” is output continuously as transmitting data. *2 : In TEST mode 6, ROW1 → 2 → 3 → 4 → COL1 → 2 → 3 → ROW1 → ... is output in the order when CHGIN

starts up at CHGCNT=H.

*3 : In TEST mode 7, increment of 1 → 2 → 3 → 4 → ...0 →

→ # is performed in the order when CHGIN starts up

at CHGCNT=H. *4 : In TEST mode 8, CHARGE LED lights when the data received is “0000 ...”. *5 : In TEST mode 9, DATA “1” is output continuously from CHGCNT, and CHARGE LED lights when CHGIN is “L”.

Channel rotation

19 → 20 → 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 “CHANNEL” 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, press the “TALK” key.

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

1 VCO/TX FREQ. ADJ 1 21 L H L L H 2 TX MOD. CHECK 2 21 L H H L L 3TX DATA 3 21 L H L L L 4 RX SENS 4 21 H H L H L 5 SQ 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: H Squelch OFF: L *1 : In TEST mode 3, “0000...” is output continuously as transmitting data. *2 : In TEST mode 6, bell (1kHz) rings lowly when the data received is “0000...”. *3 : In TEST mode 7, bell rings loudly with initial 2 tone (2kHz, 2.2kHz). *4 : In TEST mode 8, bell (1kHz) rings lowly when P BATLOW is “L”. *5 : In TEST mode 9, bell rings lowly 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 Poi nt

BASE RF PCB

RF Test Poi nt

BASE MAIN PCB

DC IN

9V Jack

TEL Line

Jack

DC 9V

AF GEN.

1kHz 45mV

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 −6.5 dBm reading on 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 926.893873 MHz.

Press the “PAGE” 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 78 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 120V 60Hz

Alignment Point Location on Base Main PCB and Base RF PCB

Base Main PCB

Base RF PCB

RT2

CT201

VR202

J201

J3 TEL LINE Jack

J2 DC IN 9V Jack

S2 T/P Switch

RF TEST POINT

Receiver Section

Connection

RF SG

AC 120V

60Hz

BASE RF PCB

Test Point

AC Adapter

DC 9V

BASE MAIN PCB

DC IN

9V Jack

TEL Line

Jack

J1 AF Terminal

Dummy Load

(600-ohm)

DC Voltmeter

AC Voltmeter

Preset

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

Alignment Procedure

Step Preset to Adjustment Remarks

Press the “PAGE” key for 3 times to enter the TEST Mode 4. Connect the

SG: 1mV

No modulation

SG: 1 mV

1 kHz ±8kHz

deviation

SG: −6.5 dBµV

No modulation

L212

(Discriminator

Voltage)

RT1

(RX AF

Voltage)

VR201

(SQ Point)

RF Signal Generator to the RF test point on the Base RF PCB. Make sure that the frequency is 902.984676 MHz. Connect the DC Voltmeter to the J1 AF test point. Adjust L212 to indicate DC 0.85 V.

Connect the RF Signal Generator to the RF test point on the Base RF PCB. Make sure that the frequency is 902.984676 MHz. Connect the AC Voltmeter across a 600-ohm dummy to the Telephone Line Jack. Adjust RT1 for a 195 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 902.984676 MHz. Adjust VR201 to turn to the point where the CHG LED just turns on.

Alignment Point Location on Handset Main PCB and Handset RF PCB

Base Main PCB

AF TEST POINT

RT1

Base RF PCB

J202

VR201

L212

J201

J3 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

Meter

RF Test Point

HANDSET RF PCB

RF Test Point

HANDSET MAIN PCB

Battery

Terminals

MIC + Pin

DC 3.8V

AF GEN.

1kHz 10.5mV

DC Power Supply

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 tes t point on the handset RF P CB . Adjust VR502 for a −7 dBm reading on the Power Met er .

Connect the Frequency Counter to the RF tes t point on the handset RF PCB. Adjust CT 501 to make sure that the frequency is 903.085147 MHz .

Press the “2” k ey to enter the TEST M ode 2. Connect the AF G ener ator to the MIC Connector. Make sure that the output is 1 kHz 10.5 mV from the AF Generator. Connect the Deviation Met er to the RF test point on the handset RF PCB. Adjust VR601 to indicat e ± 8kHz Dev.

Alignment Point Location on Handset Main PCB and Handset RF PCB

Handset Main PCB

MIC + Pin

MC601

RF PCB

VR601

CT501

RF TEST POINT

J501

VR502

Receiver Section

Connection

RF SG

HANDSET RF PCB

RF Test Point

DC Power Supply

DC 3.8V

HANDSET MAIN PCB

J602

Battery

Terminals

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 926.994344 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 926.994344 MHz. Connect the AC Voltmeter across a 150-ohm dummy to the SP Connector. Adjust VR602 for a 65 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 926.994344 MHz. Adjust VR501 to turn to the point where there is no signal on the oscilloscope.

SG: 1 mV

No modulation

SG: 1 mV

1 kHz ±8 kHz

deviation

SG: −6.5 dBµV

1 kHz ±8 kHz

deviation

L512

(Discriminator

Voltage)

VR602 (RX AF Output)

VR501

(SQ Point)

Oscilloscope

Alignment Point Location on Handset Main PCB and Handset RF PCB

AF TEST POINT

Handset Main PCB

VR602

MIC + Pin

MC601

RF PCB

J502

VR501

L512

RF TEST POINT

J501

J602 SP Connector

Base, Main

BLOCK DIAGRAMS

— 9 —

Base, RF

— 10 —

Handset, Main

— 11 —

Handset, RF

— 12 —

SCHEMATIC DIAGRAMS

Base, Main

— 13 — —14 —

Base, RF

— 15 — —16 —

Handset, Main

— 17 — —18 —

Handset, RF

— 19 — —20 —

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 59 of IC5?

Check IC5 and its peripheral circuit.

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

Check IC4 and TEL network circuit.

Check R62, R65 and C41.

Deletion of the Caller ID memory

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

1) Set the TONE/PULSE switch to TONE position.

2) While pressing the PAGE button, plug the AC power adapter into the base. Keep pressing the PAGE button for more than 2 seconds. CHARGE LED will blink rapidly.

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 ring?

When the PAGE SW S1 of the base is pressed, does pin19 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 58 of IC603 be seen?

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

Check RINGER Y601.

Check R40, R42 and S1.

Check IC603.

Check R627,R629,R667, Q605,Q606, and Q613.

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.

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, 902.984676 MHz (250 Hz ±7 kHz Dev.) 1 mV output sig nal from RF jack is applied. Can the INUSE LED be lighted?

Check IC5 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 Q1 collector.

Check RT2, R30, R31, R32 R33, R57 and C28.

Check base RF unit.

Check RT1, Q1 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 37 of IC5.

Check IC5 and its peripheral circuit.

Check IC603 and its peripheral circuit.

Check handset RF unit.

Check Q3, Q4 and their peripheral circuits.

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, 926.994344 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 .

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