Toshiba FT 7807 Service Manual

FILE NO. 2B0-9707

SERVICE MANUAL

CORDLESS TELEPHONE

FT-7807

PRINTED IN U.S.A., Oct., 1997

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

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

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

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

SCHEMATIC DIAGRAMS...................................................................................................................10

TROUBLESHOOTING HINTS ........................................................................................................... 14

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

SEMICONDUCTOR LEAD IDENTIFICATION ................................................................................... 25

ELECTRICAL PARTS LOCATION ..................................................................................................... 30

WIRING DIAGRAMS .......................................................................................................................... 32

EXPLODED VIEW AND MECHANICAL PARTS LIST ......................................................................33

PARTS LIST ........................................................................................................................................37

ASSEMBLY PARTS LIST ...................................................................................................................50

SPECIFICATIONS ..............................................................................................................................51

APPENDIX .......................................................................................................................................... 54

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 —

OPERATING CONTROLS

HANDSET CONTROLS

Liquid Crystal Display (LCD)

TALK button

0-9, , # Dial buttons

TONE button

FLASH/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.

CH (channel)/DELETE button

TALK

MEM CID

ABC

DEF



JKL

GHI

MNO



TUV

Y Z

TONE

OPER





FLASH CH VOL/RING RDL

FUNC DELETE CANCELPAUSE

Charging contacts

Helical antenna

MEM 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.

RDL(Redial)/PAUSE button VOL/RING/CHANCEL button

Battery compartment

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 while the handset is connecting to the base unit. Displayed during the caller ID review mode.

talk

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.

call id mem

mem icon

Displayed

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

-while the Function Mode is in use.

Battery icon

Displayed while the handset is being charged.

Displayed while the handset is being charged during the battery low status.

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

BASE UNIT CONTROLSLCD

Cradle

ALL DIGITAL CALLER ID CORDLESS TELEPHONE 25 CH SCANNING FT-7807

IN USE

CHARGE

POWER

LINE modular jack DC IN 9V jack

Tone/Pulse switch

Base antenna

IN USE LED CHARGE LED

PAGE

POWER LED PAGE button

— 2 —

ALIGNMENT PROCEDURE

BASE UNIT / TRANSMITTER

Test Equipment Required and Connections

• Oscilloscope • Dummy Load, 50-ohm

• Frequency Counter • AC Power Supply: 120V, 60Hz (With AC Adapter)

• Digital Voltmeter

AC Adapter

(120V 60Hz)

Base Set

J2 DC IN 9V JA C K

RF Test

Point

D um m y Load

(50-ohm )

− +

O s c illo s c o p e D ig ita l V o ltm e te r

Frequency C ounter

TX VC O Test Point

Preset

a) Set T/P SW to Pulse Mode. b) Turn on AC power while the Page key is being depressed. c) Release the Page key about 2 seconds later, then the TX Mode is entered (CH21).

Al ign me nt Proc e dur e

Step Adjustment Remarks

Connect the oscilloscope across a 50-ohm load to RF test point.

1 L10



Set the digital voltmeter at the test point of TX VCO. Adjust L10 to indicate DC 2.8 ±0.05 V (VC O).

Connect the fre

uency counter across a 50-ohm dummy load to RF test

point. Make sure that the frequency is 46.770 MHz ±1500 Hz.

Alignment Point Location on Main (Base Unit) PCB

T X V C O T e s t P o in t

L10

— 3 —

RF Test Point

T/P SW

D C IN 9V Jack

RECEIVER

Test Equipment Required and Connections

• SG: RF Signal Generator, 49.830 MHz, 49.160 MHz • Dummy Load, 600-ohm

• Digital Voltmeter • AF SSVM

• SINAD Meter

MOD = 1KHz D E V = ±3kHz

AC A dapter

(120V 60HZ)

Preset

a) Set T/P SW to Pulse Mode. b) Turn on AC power while the Page key is being depressed. c) Release the Page key about 2 seconds later, then the TX Mode is entered (CH21). d) Press the Page key 4 times, then the RX Mode is entered (CH21).

Al ign me nt Proc e dur e

Step Preset to Adjustment Remarks

SG: 1 mV

No modulation

SG: 1 mV

1 kHz ±3kHz

deviation

SG: 1 mV

1 kHz ±3 kHz

deviation

SG: 1 mV

1 kHz ±3 kHz

deviation

Base Set AF SSVM

D um m y Load

− +

RF Test Point

TEL Jack

(6 00-oh m )

SINAD

Meter

RX VCO Test Point

Connect the SG to the RF test point.

Connect the digital voltmeter to the test point of the RX VCO. Adjust L7 to indicate DC 1.4 ±0.05 V.

Connect the di Adjust L3 to indicate DC 2.0 ±0.05V.

ital voltmeter to the test point of Discriminator.

RT1 Adju s t RT1 t o make AF SSVM value −5 dBm ±0.5 dB.

Set T/P SW to TONE Mode. Press th e Pa chan

es to CH 8.

Connect th e A F SSVM t o the TEL LIN E across a 600-oh m du m m Keep the SINAD readin

at 12 dB by adjusting the SG output. Adjust

L6 for maximum SI NAD reading.

D ig ita l V o ltm e te r

e key once, t hen CH

load.

Alignment Point Location on Main (Base Unit) PCB

RT1

RF Test Point

RX VCO Test Point

T/P S W

DC IN 9V Jac

D is c rim in a to r Test Point

— 4 —

HANDSET / TRANSMITTER

Test Equipment Required and Connections

• DC Power Supply, 3.6V • Digital Voltmeter

Frequency C ounter

D ig ita l V o ltm e te r

TX VC O Test Point

D C P ow er S upply

3.6V

Handset

RF Test Point

B a tt T e rm in a l

− +

D um m y Load

(50-ohm )

Preset

Turn Power on while depressing “ ” and “#” keys. A beep will be heard. Then the TX Mode is entered (CH21).

Al ign me nt Proc e dur e

Step Adjustment Remarks

1 L509



Set the di indicate DC 2.0 V ±0.05 V at CH21.

Connect the fre point. Make sure that the frequency is 49.830 MHz ±1500 Hz.

ital voltmeter at the test point of TX VC O, then adjust L509 to

uency counter across a 50-ohm dummy load to RF test

Alignment Point Location on Main (Handset Unit) PCB

L504

RF Test Point

L509

TX VC O

Test Point

J501

Battery Term inal

— 5 —

RECEIVER

(

)

(

)

(

)

(

)

(

)

Test Equipment Required and Connections

• SG: RF Signal Generator, 46.770 MHz, 46.610 MHz • Dummy Load, 150-ohm

• VTVM • DC Power Supply: 3.6 V

• Digital Voltmeter • SINAD Meter

− +

MOD = 1KHz D E V = ±3kHz

D C P ow er S upply

3.6V

Preset

a) Turn Power on while depressing “ ” and “#” keys. A beep will be heard. Then the TX Mode is entered (CH21). b) Press “4” key, then the RX ADJ Mode is entered (CH21).

Al ign me nt P ro cedur e

Step Preset to Adj ustment Remarks

1 L505

SG: 1 mV

CH21

MOD OFF

SG: 1 mV

CH21

1 kHz ±3 kHz dev.

SG: 158

CH16

1 kHz ±3 kHz dev.

SG: 3

CH16

1 kHz ±3 kHz dev.

SG: 1

CH16

1 kHz ±3 kHz dev.

Handset VTVM

D um m y Load RF Test Point

Term inal

B a tt T e rm in a l

RX VCO / D iscrim inator Test Point

Connect the di

(1 50-oh m )

D ig ita l V o ltm e te r

SINAD

Meter

SP Term inal across D um m

Load

ital voltmet er to the t est point (RX VCO).

Adjust for 1.4 V DC at CH21.

L502

RT501

L510

Connect the di Adjust for 1.1 V DC at CH21.

Connect the VTVM to the speaker terminal. Adjust for 115 mV on the VTVM (SP. OUT ) at CH21.

Press the “CH” twic e to chan Adjust for maximum SINAD on t he SINAD M ETE R at CH1 6.

ital voltmet er to the t est point (Discriminator).

e th e ch annel t o C H16.

L510 Adj us t for maximu m SI NAD on the S I NA D m et er at CH16 .

Alignment Point Location on Main (Handset Unit) PCB

D is c rim in a to r Test P oint

L505

L510

Term inal

Test P oint

RX VCO

Test P oint

J502

L504

R T501

L502

J501

Battery Term inal

— 6 —

Base

BLOCK DIAGRAMS

— 7 —

Handset

— 8 — — 9 —

TEST PO IN T

(Discrim inator)

SCHEMATIC DIAGRAMS

(R F )

TEST PO IN T

100ÊH

L13

C53

C32

0.1/B 50V 10

T ES T PO IN T (TX V C O)

(R X V C O )

TEST PO IN T

— 10 — — 11 —

Base Unit

TEST POINT

(D escrim inator)

T E ST P O IN T (TX V C O )

— 12 — — 13 —

(RX VCO)

TEST POINT

(R F )

TEST POINT

Handset Unit

C h e c k R 5 3 , R 7 4 , R 7 1 ,

By using voltage chart,

check the base T X circu it.

R 75 and R 76.

C heck the handset R X R F

circuit (Q 501) as well as

FT501 and FT503.

C heck R505, C 511 and

C539.

C heck IC503.

C heck R556, R 561, R 569,

Q 507 and Q 512.

C heck S2, R 27 and R 84.

IC 2 is defective.

C an the base and handset

deviation.

C heck the handset R X

s e n s it iv ity .

C heck R X data pulse

w aveform ing current

(P in 1 5 o f IC 504).

C heck the base TX power.

be connected?

C heck the base TX data

C heck R 51 5.

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

W hen the key of the

Press handset D IA L key

handset is pressed, can

the pulse output at pin 58

of IC 503 be seen?

w h ile in T A L K M O D E . C a n

key touch sound be heard

from the ringer?

At the Q 507 and Q 512

collector, can the pulse

w ave be seen?

RINGER is defective.

W hen the PAG E S W of the

base is pressed, does

Pin 53 of IC2 change from

high to low?

C heck the surrounding

circuit w here the voltage is

By using voltage chart,

check IC 2 .

incorrect.

IC 3 is defective.

C heck TE L netw ork

By using voltage chart,

check IC 3.

prim ary circuit.

See 2. The bell does not ring

& page does not ring.

TROUBLESHOOTING HINTS

W hen the PAG E S W of the

base is pressed, does the

ringer on the handset ring?

W hen the TEL SG is joined

1. The bell does not ring.

w ith the base to m ake bell

signal, is there pulse w ave

on P in 4 of IC3?

— 14 — — 15 —

IC 2 is defective.

By using voltage chart,

check IC 2.

C heck the surrounding

c ircu it w h e r e th e

voltage is incorrect.

Keep the AC adaptor connected to the wall outlet. Make sure that

the telephone line cord remains disconnected during this

You can cancel the Caller ID memory by the following process.

procedure.

1. Disconnect the AC adaptor and telephone line cord from the base.

base. Keep pressing the PAGE button for more than 2 seconds.

2. Set the Tone/Pulse switch to "Tone" position.

3. While pressing PAGE button, plug the AC power adaptor into the

C heck IC 2, R 30 and R 48.

Then, is there pulse w ave

on P in28 of IC 2?

3. The base and handset cannot connect.

C heck w hether the handset and the base unit are connected.

C heck the handset TX POW ER.

C heck the base TX pow er.

C heck the base TX data deviation.

C heck the handset R X s e n s itiv ity .

C heck the handset R X data pulse w ave form ing current (Pin 15 of IC 503).

Check R515.

By using voltage chart, check the base TX circuit.

C h e c k R 5 3 , R 7 4 , R 7 1 , R 75 and R 76.

C heck the handset R X R F and m ixer circuit (Q 501) as w ell as FT501 and FT503.

Check R505, C511 and C539.

By using voltage chart, check the handset TX circuit.

C heck the handset data deviation.

C heck the base R X s e n s itiv ity .

Then, can the sine wave be seen at P in 24 of IC 1 ?

NG NG

C heck the handset M IC s e n s itiv ity .

C heck the handset data circuit (R 540, R 541, R 584, and R 587).

C heck the base R X TE L OUT.

C heck the base R X R F and m ixer circuit (around Q 1) as w ell as FT3 and FT2.

C heck the handset TX AF circuit (around Pins 17, 19 ~ 21 of IC 504).

In th e b a s e , w ith th e S G standard m odulation of 1 k H z 3 k H z d e v ia tio n a n d input signal of 1m V , can the sine w ave be seen at P in 2 5 o f IC 1 ?

C heck the base IF circuit (around Pins 26~29 of IC 1 ).

C heck circuit around Pin 24 o f IC 1 .

— 16 —

Then, can the sine wave be seen at the Q 2 C ollector.

C heck the surrounding c irc u it o f T 1 .

4. Cannot make a phone call (pulse).

C heck Q 2 and surrounding c irc u it o f Q 2 .

C an the base and handset be connected?

W h ile in T A L K M O D E , press dial key of the handset. C an pulse feedback be heard from the handset speaker?

C heck the base TEL-line n e tw o rk p rim a ry circu it.

5. Cannot make a phone call (tone).

C an the base and handset be connected?

W h ile in T A L K M O D E , press dial key of the handset. From the speaker, does the TO N E ring up?

C heck the base m odulation s e n s itiv ity .

See 3. The base and handset cannot connect.

C heck the base R E LA Y control (around Pin23 o f IC 2 .

See 3. The base and handset cannot connect.

C heck the base TX AF circuit (around Pins 17, 19~21 of IC 1).

C heck the base TEL-line circuit and R E LAY control circuit.

A t P in 2 0 o f IC 5 o f th e base, can the TO N E w ave output be seen?

C heck R 45, R 46, R 49 and C56.

— 17 —

C heck IC 5 by using voltage chart.

6. Voice cannot be transmitted to other party (outgoing call).

C heck the handset M IC s e n s itiv ity .

C heck the handset TX AF circuit (around Pins 17, 19~21 of IC 504).

At the M IC of the handset, does the bias voltage exist?

C heck the base R X TE L-line out.

Then, can the sine wave be seen at P in 24 of IC 1 ?

Then, can the sine w ave be seen at the Q 2 collector?

C heck R 548, R 534, R 532 and C 555.

In th e b a s e , w ith th e S G standard m odulation of 1 k H z 3 k H z d e v ia tio n a n d input signal of 1m V , can the sine w ave be seen at P in 2 5 o f IC 1 ?

C heck the base IF circuit (around Pins 26~29 of IC 1 ).

C heck circuit around Pin 24 o f IC 1 .

C heck Q 2 and the sorrounding circuit of Q 2.

C heck the base R X s e n s itiv ity .

OK OK

The handset M IC is defective.

C heck the sorrounding c irc u it o f T 1 .

C heck the base R X TE L-line out.

C heck R X R F and m ixer circuit of the base (around Q 1) as w ell as FT3 and FT2.

— 18 —

+ 35 hidden pages

Toshiba FT 7807 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

CONTENTS

OPERATING CONTROLS

ALIGNMENT PROCEDURE

BLOCK DIAGRAMS

SCHEMATIC DIAGRAMS

TROUBLESHOOTING HINTS