TOSHIBA ft8989 Service Manual

FILE NO. 2B0-9905

SERVICE MANUAL

CORDLESS TELEPHONE

FT-8989

PUBLISHED IN JAPAN, Sep., 1999

CONTENTS

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

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

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

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

SCHEMATIC DIAGRAMS..........................................................................................................12

TROUBLESHOOTING HINTS ...................................................................................................18

IC AND TRANSISTOR VOLTAGE CHART ............................................................................... 25

SEMICONDUCTOR LEAD IDENTIFICATION........................................................................... 32

ELECTRICAL PARTS LOCATION............................................................................................. 35

WIRING DIAGRAMS .................................................................................................................38

EXPLODED VIEW AND MECHANICAL PARTS LIST............................................................... 41

PARTS LIST............................................................................................................................... 45

ASSEMBLY PARTS LIST .......................................................................................................... 64

SPECIFICATIONS ..................................................................................................................... 65

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.

1

OPERATING CONTROLS

HANDSET CONTROLS AND FUNCTIONS LCD

Dot matrix display

VOL/RING ( ) button
(up arrow button)

VOL/RING ( ) button

Liquid Crystal Display
(LCD)

REDIAL ( ) button
(Left arrow button)

TALK button
1 button

(TONE) button

MEM (Memory) button
PAUSE button
FUNC (Function) button

DELETE CH button
Charging contacts

(down arrow button)
FLASH ( ) button

(Right arrow button)
SELECT button

CID (Caller ID) button

dialpad

Caller's telephone number
Caller's name

Battery compartment

Number of calles

Date Time

BASE UNIT CONTROLS AND FUNCTIONS

DC in 9V Jack
TEL LINE Jack

OGM button
ANSWER button

REPEAT button
PIN button

IN USE LED
CHARGE LED
POWERR LED

T-P (TONE-PULSE) switch
Ringer ON/OFF switch

Speaker

Antenna
LED Display

VOLUME button
DELETE button
MEMO/2WAY REC button

PLAY/STOP button
PAGE button

SKIP button
Rec Time Switch (ANN/4/1)
CLOCK button
Ring Time Switch (2/4/TS)

SPEAKER button
Speaker LED

Microphone

2

ALIGNMENT PROCEDURE

Test Mode For Base Unit

Press the “PAGE” key about 3.0 seconds while turning the power on.

1. To change the TEST mode: Press the “PAGE” key with T/P s witch to PULSE position.

2. To change channel: Press the “PAGE” key with T/P switch to TONE position. If changing the step, the
channel returns to the start channel.

3. To cancel Test mode: Bell rings, charge the Handset or Power off.

STEP

1

VCO/TX FREQ. ADJ

2

TX MODE CHECK

3

TX DATA

4

RX SENS.

5

SQ SENS.

6

SINGLE TONE CHECK

7

DUAL T ONE CHECK

8

DATA IN CHECK

9

CHANNEL DATA CHECK

10

*A : CHARGE LED is ON when SQ ON, CHARGE LED is OFF when SQ OFF.
*1 : “0000...” (250Hz) will be fed out contin uously as tr ansmitting data.
*2 : CHARGE LED lights when the received data are “0000...”.

DUPLEX

FUNCTION

START CH

19
19
19
19
19
19
19
19
19
19

TX CONT

L
L

L
H
H
H
H
H
H

L

TX MUTE

L

H

L
L
L
L
L
L
L

H

Channel rotation

19ð20ð21ð40ð1ð25ð2ð3........24ð26........38ð39ð40

RX MUTE

L
L
L

H

*A

L
L
L
L

H

RL CONT

L

H

L
H
H
H
H

L

L
H

REMARKS

*1

*2

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 follwing tabl e .)

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

2. To change channel: Press “CH” k ey.
(Note: If the step is changed, the channel return to the start channel.)

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

STEP

1
2
3
4
5
6
7
8
9

10

*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 (2kHz, 2.2kHz) 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 (2kHz, 2.2kHz) rings when P_BATLOW is “L”.
*5 : In the TEST mode 9, bell (2kHz, 2.2kHz) rings when P_CHRGIN is “L”

FUNCTION
VCO/TX FREQ. ADJ
TX MOD . CHECK
TX DATA
RX SENS
SQ SENS
RECEIVE DATA CHECK
BELL
BATTERY LOW CHECK
CHARGE CHECK
DUPLEX

KEY

1
2
3
4
5
6
7
8
9
0

START CH

21
21
21
21
21
21
21
21
21
21

TX CONT

L
L
L

H

L

L
H
H
H

L

SC

H
H
H
H
H
H

L
L
L

H

TX MUTE

L

H

L
L
L
L
L
L
L

H

RX MUTE

*A

Channel rotation

21ð20ð19ð40ð1ð25ð2ð3........24ð26........38ð39ð40

CONV
L
L
L

H

L
L
L
L

H

H

L
L
L

L
H
H
H
H

L

REMARKS

*1

*2
*3
*4
*5

4

Base Unit

Transmitter Section

Connections

Preset

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

Alignment Procedure

Power

Meter

Frequency

Counter

Deviation

Mater

RF
Test Point

RF
Test Point

BASE Unit

J4
DC IN
9V Jack

TEL Line

Jack

J1

1kHz 77.5mV

AF GEN.

AC

Adapter

AC 120V
60Hz

step

1

2

Adjustment

RT301

(TX P ower)

CT1

(TX Frequency)

Remarks

Connect the Po w er Meter to the RF test point on the Base MAIN PCB.
Adjust RT301 for a -6.5dBm 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 “PAGE” k e y to enter the TEST Mode 2. Connect the AF Generator

3

RT3

(TX Modulation)

to the TEL Line J a ck on the Base Main PCB. Mak e 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 De v.

Alignment Point Location on Base Main PCB and Base RF PCB

Base Main PCB

RT3

J1
TEL LINE Jack

J4
DC IN 9V Jack

T

S1
T/P Switch

P

CT1

5

Base RF PCB

RT301

RF Test Point

Receiver Section

Connections

RF SG

­+

RF
Test Point

TEL Line

Jack

J1

Dummy Load

(600-ohm)

­+

AC V oltmeterBASE Unit

AC 120V

60Hz

AC

Adapter

DC IN 9V Jack

J4

AF
Terminal

DC V oltmeter

Preset

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

Alignment Procedure

step

Preset to

1

SG: 1mV

No modulation

SG: 1mV

2

1 kHz ±8kHz

deviation

SG: -6.0 dB

3

No modulation

Adjustment

(Discriminator

Voltage)

(RX AF

Voltage)

µµ

µV

µµ

(SQ Point)

L3

RT2

RT1

Remarks

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 L4 to indicate DC

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

Jack. Adjust RT2 for a 245 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 bell rings.

Alignment Point Location on Base Main PCB and Base RF PCB

Base Main PCB

RT1

RT2

L3

AF Test Point

RF Test Point

J1
TEL LINE Jack

J4
DC IN 9V Jack

T

S1
T/P Switch

P

6

Handset Unit

Transmitter Section

Connection

RF

Power

Meter

Frequency

Counter

Deviation

Mater

Test Point

RF
Test Point

Preset

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

Alignment Procedure

HANDSET Unit

J603
Battery
Connector

MIC+Pin

DC 3.8V

AF GEN.

1kHz 9mV

DC Power Supply

step

1

2

Adjustment

RT501

(TX P ower)

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

3

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

MC601

J603

RF PCB

RT501

CT601

RF Test Point

7

Receiver Section

Connections

RF SG

­+

RF
Test Point

SP

Connector

Dummy Load

(150-ohm)

­+

AC V oltmeterHANDSET Unit

DC Power Supply

Battery

Connector

DC 3.8V

J603

AF
Terminal

DC V oltmeter

Preset

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

Alignment Procedure

step

Preset to

1

SG: 1mV

No modulation

SG: 1mV

1 kHz ±8kHz

2

deviation

SG: -6.0 dB

3

No moduration

Adjustment

L603

(Discriminator

Voltage)

RT602

(RX AF

Voltage)

µµ

µV

µµ

RT601

(SQ Point)

Remarks

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 35 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.

Alignment Point Location on Handset Main PCB and Handset RF PCB

Handset PCB

J603

Discriminator Test Point

RT602

RT601

L603

8

RF PCB

RF Test Point

Base Unit, Main

BLOCK DIAGRAMS

9

Base Unit, DSP

10

Handset

11

Base Unit, Main

SCHEMATIC DIAGRAMS

12

13

Base Unit, Key

14

15

Handset

16

17

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 IC1?

Is there pulse wave at
pin 24 of IC6?

Check IC6 and its
peripheral circuit.

BASE UNIT

OK

OK

OK

NG

NG

NG

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

Check IC1 and TEL network
circuit.

Check R56, R84, R83 and
C79.

If you want to reset the unit to the factory settings

You can cancel the OGM, PIN, and the clock settings by the following process.

1) Disconnect the AC adaptor and telephone line cord from the base. Keep the AC adaptor connected to the w all
outlet. Make sure that the telephone line cord remains disconnected during this procedure.

2) While pressing the DELETE button, plug the AC power adaptor into the base. Keep pressing the DELETE
button for more than 4 seconds .
A beep sounds and “ P” blinks in the LED display.

To resume using the unit, connect the telephone line cord and place the handset on the base.

Note:
If you turn on the unit again, “ P” may flash.

HANDSET

Delection of the Caller ID memory

To delete the Caller ID memory in the EEPROM, proceed with the following 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.)

18

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

Can the base and handset be
connected?

OK

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

OK

When the PAGE SW of the
base is pressed, does pin82
of IC6 change from high to
low?

NG

NG

NG

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?

OK

At the Q616 collector, can the
pulse wave be seen?

OK

Check RINGER Y601.

Check R178, R165 and S5.

NG

NG

Check IC603.

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

OK

Check IC4 and its peripheral
circuit.

19

3. The base and handset cannot be connected.

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

OK

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

OK

Set the base in the test
mode 3, check whether
deviation of the TX data
is app. 8.5 kHz Dev.

OK

Set the base in the test
mode 8, 902.952467
MHz (250 Hz ±8 kHz
Dev.) 1mV output signal
from RF test point is
applied. Does the
CHARGE LED light?

OK

NGACheck IC6 and its

peripheral circuit.

NG

Check base RF unit.

Check whether there is a

NG

250 Hz data wavef orm at
“MOD” of RF unit.

OK

Check base RF unit.

NG Check whether there is a

250 Hz data wavef orm at
RT2 AF test point.

OK

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

OK

Check RT3, R51, R52,

NG

R53, R48, R80, R81,
C59, C135 and C54.

Check IC2, Q1 and their

NG

peripheral circuit.

Check RT2, Q2 and their

NG

peripheral circuit.

OK

NG

Check base RF unit.

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

OK

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

OK

Check whether there is a
250 Hz data wavef orm at
pin 44 of IC6.

OK

Check IC6 and its
peripheral circuit.

NG Check IC603 and its

peripheral circuit.

NG

Check handset RF unit.

Check IC3 and its

NG

peripheral circuit.

20

A

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

OK

Press “6” key,

926.997467 MHz (250
Hz ±8 kHz Dev.) 1mV
output signal from RF
jack is applied. Check
whether the bell ring.

OK

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.

OK

Check handset RF unit.

NG Check whether the 250

Hz data waveform from
pin 9 of IC606 is fed.

OK

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

OK

Check whether there is a
250 Hz data wavef orm at
pin 55 of IC603.

OK

Check R635, R636,

NG

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

Check handset RF unit

NG

and the peripheral circuit
of IC606.

Check RT602, Q601 and

NG

their peripheral circuit.

Check IC601 and their

NG

peripheral circuit.

Check IC603 and its
peripheral circuit.

21

4. Cannot make a phone call (pulse).

Can the base and handset
be connected?

OK

While in TALK MODE, press
dial key of the handset.
Check whether square
waveform from pin 23 of IC6
is fed.

OK

Check Q6, RL1 and their
peripheral circuits.

NG

NG

See 3. The base and handset
cannot be connected.

Check IC6.

5. Cannot make a phone call (tone).

Can the base and handset be
connected?

OK

NG

See 3. The base and handset
be cannot be connected.

While in TALK MODE, press
dial key of the handset.
Can tone waveform from Pin
20 of IC7 is fed?

OK

Can tone signal be heard
from the handset speaker?

OK

Check the base TEL-line
circuit and RELAY control
circuit.

NG

NG

Check IC7.

Check IC4, Q3 and their
peripheral circuits.

22