Toshiba FT 7807R Service Manual
FILE NO. 2B0-9803
SERVICE MANUAL
CORDLESS TELEPHONE
FT-7807R
PUBLISHED IN JAPAN, Jun., 1998
CONTENTS
SAFETY PRECAUTIONS ...................................................................................................................... 1
OPERATING CONTROLS ...................................................................................................................2
ALIGNMENT PROCEDURE.................................................................................................................3
BLOCK DIAGRAMS..............................................................................................................................7
SCHEMATIC DIAGRAMS.....................................................................................................................9
TROUBLESHOOTING HINTS ........................................................................................................... 13
IC AND TRANSISTOR VOLTAGE CHART ....................................................................................... 19
SEMICONDUCTOR LEAD IDENTIFICATION...................................................................................23
ELECTRICAL PARTS LOCATION ..................................................................................................... 27
WIRING DIAGRAM.............................................................................................................................29
EXPLODED VIEW AND MECHANICAL PARTS LIST ...................................................................... 30
PARTS LIST ........................................................................................................................................34
ASSEMBLY PARTS LIST ...................................................................................................................48
SPECIFICATIONS .............................................................................................................................. 49
APPENDIX .......................................................................................................................................... 52
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 —
HANDSET CONTROLS
ging
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
OPERATING CONTROLS
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.
TALK
MEM CID
ABC
DEF
JKL
GHI
MNO
"
#
PQ
WX
TUV
RS
Y Z
%
&
TONE
OPER
FLASH CH VOL/RING RDL
FUNC DELETE CANCELPAUSE
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
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.
call id mem
Char
mem icon
Displayed
-while data is being stored in an
deleted from memory.
-while the Function Mode is in
use.
contacts
Battery icon
Displayed while the handset is being
charged.
BASE UNIT CONTROLSLCD
Cradle
ALL DIGITAL CALLER ID
CORDLESS TELEPHONE
25 CH SCANNING FT-7807
IN USE
CHARGE
POWER
PAGE
LINE modular jack
DC IN 9V jack
Tone/Pulse switch
Base antenna
IN USE LED
CHARGE LED
POWER LED
PAGE button
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.
Displayed while the handset is being
charged during the battery low status.
Blinks when the battery low status
occurs during standby and phone
conversation.
— 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 Unit
J2
DC IN 9V
JACK
RF Test
Point
Dummy Load
(50-ohm)
−
+
Oscilloscope Digital Voltmeter
Frequency Counter
TX VCO
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).
Alignment Procedure
Step Adjustment Remarks
Connect the oscilloscope across a 50-ohm load to RF test point.
1L10
2
Set the digital voltmeter at the test point of TX VCO.
Adjust L10 to indicate DC 2.8 ±0.05 V (VCO).
Connect the frequency 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
TX VCO Test Point
L10
— 3 —
RF Test Point
L1
S1
J2
P
T/P SW
T
DC IN 9V J a c k
RECEIVER
k
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
SG
+
MOD = 1KHz
DEV = ±3kHz
Base Unit AF SSVM
Dummy Load
RF Test
Point
TEL Jack
(600-ohm)
Digital Voltmeter
AC Adapter
(120V 60HZ)
SINAD
Meter
RX VCO
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).
d) Press the Page key 4 times, then the RX Mode is entered (CH21).
Alignment Procedure
Step Preset to Adjustment Remarks
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 digital voltmeter to the test point of Discriminator.
Adjust L3 to indicate DC 2.0 ±0.05V.
Adjust RT1 to make AF SSVM value −5 dBm ±0.5 dB.
Set T/P SW to TONE Mode. Press the Page key once, then CH
changes to CH 8.
Connect the AF SSVM to the TEL LINE across a 600-ohm dummy
load.
Keep the SINA D re ad in g at 12 d B b y a dj usti ng t h e S G ou tp ut . Adju st
L6 for maximum SINAD reading.
1
No modulation
2
3
1 kHz ±3 kHz
4
1 kHz ±3 kHz
SG: 1 mV
SG: 1 mV
1 kHz ±3kHz
deviation
SG: 1 mV
deviation
SG: 1 mV
deviation
L7
L3
RT1
L6
Alignment Point Location on Main (Base Unit) PCB
RT1
— 4 —
L3
L7
RF Test Point
L1
L6
S1
J2
RX VCO
Test Point
P
T/P SW
T
DC IN 9V Jac
Discriminator
Test Point
HANDSET / TRANSMITTER
Test Equipment Required and Connections
• DC Power Supply, 3.6V • Digital Voltmeter
Frequency Counter
Digital Voltmeter
TX VCO
Test Point
DC Power Supply
3.6V
Handset Unit
RF Test Point
Batt Termin a l
Dummy Load
(50-ohm)
+
Preset
Turn Power on while depressing “ ” and “#” keys. A beep will be heard. Then the TX Mode is entered (CH21).
Alignment Procedure
Step Adjustment Remarks
1L509
2
Set the digital voltmeter at the test point of TX VCO, then adjust L509 to
indicate DC 2.0 V ±0.05 V at CH21.
Connect the frequency counter across a 50-ohm dummy load to RF test
point. Make sure that the frequency is 49.830 MHz ±1500 Hz.
Alignment Point Location on Main (Handset Unit) PCB
L504
L509
RF
Test Point
TX VCO
Test Point
J501
Battery
Terminal
— 5 —
RECEIVER
y
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
SG
MOD = 1KHz
DEV = ±3kHz
DC Power Supply
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).
Alignment Procedure
Step Preset to Adjustment Remarks
1L505
SG: 1 mV
2
3
4
5
6
(CH21)
MOD OFF
SG: 1 mV
(CH21)
1 kHz ±3 kHz dev.
SG: 158 µV
(CH16)
1 kHz ±3 kHz dev.
SG: 3 µV
(CH16)
1 kHz ±3 kHz dev.
SG: 1 µV
(CH16)
1 kHz ±3 kHz dev.
L502
RT501
L510
L510 Adjust for maximum SINAD on the SINAD meter at CH16.
L510 Adjust for maximum SINAD on the SINAD meter at CH16.
Handset Unit VTVM
Dummy Load
+
RF Test
Point
Terminal
Batt Termin a l
RX VCO /
Discriminator
Test Point
SP
(150-ohm)
Digital Voltmeter
SP Terminal
across Dumm
Connect the digital voltmeter to the test point (RX VCO).
Adjust for 1.4 V DC at CH21.
Connect the digital voltmeter to th e test point (Discriminator).
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” twice to change the channel to CH16.
Adjust for maximum SINAD on the SINAD METER at CH16.
SINAD
Meter
Load
Alignment Point Location on Main (Handset Unit) PCB
Discriminator
Test Point
Terminal
RF
Test Point
RX VCO
Test Point
SP
L510
L504
L505
J502
L502
RT501
— 6 —
J501
Battery
Terminal
— 7 —
— 8 —
TEST POINT
(Discriminator)
— 10 —
SCHEMATIC DIAGRAMS
(RF)
TEST POINT
TEST POINT
TEST POINT(TX VCO)
(RX VCO)
— 9 —
TEST POINT
(Discriminator)
— 12 —
TEST POINT(TX VCO)
TEST POINT
(RX VCO)
— 11 —
TEST POINT
(RF)
TROUBLESHOOTING HINTS
1. The bell does not ring.
When the PAGE SW of the
base is pressed, does the
ringer on the handset ring?
OK
When the TEL SG is joined
with the base to make bell
signal, is there pulse wave
on Pin 4 of IC3?
OK
Then, is there pulse wave
on Pin30 of IC2?
OK
By using voltage chart,
check IC2.
NG
NG
By using voltage chart,
check IC3.
Check TEL network
primary circuit.
NG
Check IC2, R30 and R48.
NG
IC2 is defective.
See 2. The bell does not ring
& page does not ring.
NG
IC3 is defective.
OK
OK
Check the surrounding
circuit where the
voltage is incorrect.
— 13 —
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?
NG
NG
Check the base TX power.
OK
Check the base TX data
deviation.
OK
Check the handset RX
sensitivity.
OK
Check RX data pulse
waveforming current
(Pin 15 of IC504).
OK
Check R515.
When the key of the
handset is pressed, can
the pulse output at pin 58
of IC503 be seen?
NG
NG
NG
NG
NG
By using voltage chart,
check the base TX circuit.
Check R53, R74, R71,
R75 and R76.
Check the handset RX RF
circuit (Q501) as well as
FT501 and FT503.
Check R505, C511 and
C539.
Check IC503.
OK
When the PAGE SW of the
base is pressed, does
Pin 28 of IC2 change from
high to low?
OK
By using voltage chart,
check IC2.
OK
Check the surrounding
circuit where the voltage is
incorrect.
NG
NG
OK
At the Q507 and Q512
collector, can the pulse
wave be seen?
OK
RINGER is defective.
NG
Check R556, R561, R569,
Q507 and Q512.
Check S2, R27 and R84.
IC2 is defective.
— 14 —
3. The base and handset cannot connect.
Check whether the
handset and the base unit
are connected.
OK
Check the handset TX
POWER.
OK
NG
NG
Check the base TX power.
OK
Check the base TX data
deviation.
OK
Check the handset RX
sensitivity.
OK
Check the handset RX
data pulse wave forming
current (Pin 15 of IC503).
OK
Check R515.
NG
NG
NG
NG
By using voltage chart,
check the base TX circuit.
Check R53, R74, R71,
R75 and R76.
Check the handset RX RF
and mixer circuit (Q501) as
well as FT501 and FT503.
Check R505, C511 and
C539.
By using voltage chart,
check the handset TX
circuit.
Check the handset data
deviation.
OK
Check the base RX
sensitivity.
Then, can the sine wave
be seen at Pin 24 of IC1?
OK
NG
NG NG
NG
Check the handset MIC
sensitivity.
OK
Check the handset data
circuit (R540, R541, R584,
and R587).
Check the base RX TEL
OUT.
OK
Check the base RX RF and
mixer circuit (around Q1)
as well as FT3 and FT2.
NG
Check the handset TX AF
circuit (around Pins 17,
19 ~ 21 of IC504).
In the base, with the SG
standard modulation of
1kHz 3kHz deviation and
input signal of 1mV, can
the sine wave be seen at
Pin 25 of IC1?
OK
Check the base IF circuit
(around Pins 26~29 of IC1).
C heck circuit around P in 24
o f IC 1 .
NG
— 15 —
Then, can the sine wave
be seen at the Q2 Collector.
OK
Check the surrounding
circuit of T1.
NG
4. Cannot make a phone call (pulse).
Check Q2 and surrounding
circuit of Q2.
Can the base and handset
be connected?
OK
While in TALK MODE,
press dial key of the
handset. Can pulse
feedback be heard from
the handset speaker?
OK
Check the base TEL-line
network primary circuit.
NG
NG
5. Cannot make a phone call (tone).
Can the base and handset
be connected?
OK
NG
See 3. The base and
handset cannot connect.
Check the base RELAY
control (around Pin23
of IC2.
See 3. The base and
handset cannot connect.
While in TALK MODE,
press dial key of the
handset. From the
speaker, does the TONE
ring up?
OK
Check the base TEL-line
circuit and RELAY control
circuit.
NG
Check the base modulation
sensitivity.
OK
At Pin 20 of IC5 of the
base, can the TONE
wave output be seen?
OK
Check R45, R46, R49 and
C56.
— 16 —
NG
NG
Check the base TX AF
circuit (around Pins 17,
19~21 of IC1).
Check IC5 by using
voltage chart.
6. Voice cannot be transmitted to other party (outgoing call).
Check the handset MIC
sensitivity.
OK
Check the handset TX AF
circuit (around Pins 17,
19~21 of IC504).
NG
At the MIC of the handset,
does the bias voltage exist?
OK
Check the base RX
TEL-line out.
OK
Then, can the sine wave
be seen at Pin 24 of IC1?
OK
Then, can the sine wave be
seen at the Q2 collector?
NG
NG
NG
NG
Check R548, R534, R532
and C555.
In the base, with the SG
standard modulation of
1kHz 3kHz deviation and
input signal of 1mV, can
the sine wave be seen at
Pin 25 of IC1?
OK
Check the base IF circuit
(around Pins 26~29 of IC1).
Check circuit around Pin 24
of IC1.
Check Q2 and the
sorrounding circuit of Q2.
NG
Check the base RX
sensitivity.
OK OK
The handset MIC is
defective.
NG
OK
Check the sorrounding
circuit of T1.
Check the base RX
TEL-line out.
Check RX RF and mixer
circuit of the base (around
Q1) as well as FT3 and
FT2.
NG
— 17 —
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