SERVICE MANUAL
PUBLISHED IN JAPAN, Oct., 1998
FILE NO. 2B0-9806
FT-8908
CORDLESS TELEPHONE
-- 1 --
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 ..................................................................................... 40
ELECTRICAL PARTS LOCATION ...................................................................................................... 46
WIRING DIAGRAMS ........................................................................................................................... 52
EXPLODED VIEW AND MECHANICAL PARTS LIST ........................................................................ 54
PARTS LIST ........................................................................................................................................ 58
ASSEMBLY PARTS LIST .................................................................................................................... 80
SPECIFICATIONS ............................................................................................................................... 81
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 ,Åin 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.
-- 2 --
OPERATING CONTROLS
BASE UNIT CONTROLS
HANDSET CONTROLS
TALK/BATT LOW LED (Red)
· Standby status : OFF
· Lights ON during a phone
conversation using the handset.
· Blinks when a channel is changed,
and during the low battery status.
TALK button
TONE button
PAUSE button
Charging Contacts
Battery compartment (back)
Antenna
VOL/RING button
SPEED DIAL INDEX (back)
Dialpad (0~9,
and # buttons)
FLASH button
RDL (Redial) button
MEM (Memory) button
CH (Channel) button
TEL LINE jack
DC IN 9V jack
CHARGE LED
Tone/Pulse switch
RINGER ON/OFF switch
Antenna
PAGE button
Microphone
REC TIME switch (ANN/4/1)
RING TIME switch (2/4/TS)
CLOCK button
SKIP button
MEMO 2WAY REC button
DELETE button
VOLUME button
POWER LED
Lights in different colors depending
on the operation status as follows:
·Orange: AC adaptor operation with
the base battery.
·Red: AC adaptor operation without
the base battery.
·Green: Base battery operation during
a power failure.
IN USE LED
REPEAT button
ANSWER button
OGM button
LED display
Speaker
PLAY/STOP button
PIN button
-- 3 --
ALIGNMENT PROCEDURE
Test Mode For Base Unit
Press the "PAGE" key about 1.5 seconds while turning the power on.
1. To change the TEST mode: Press the "PAGE" key with T/P switch 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.
*A : CHARGE LED is ON when SQ ON, CHARGE LED is OFF when SQ OFF.
*1 : "0000..." (250Hz) will be fed out continuously as transmitting data.
*2 : CHARGE LED lights when the received data are "0000..." .
Channel rotation
19
20 21 40 1 2 3 4 5 . . . . . . . . 37 38 39 40
STEP
FUNCTION
START CH
TX CONT
TX MUTE
RX MUTE
RL CONT
REMARKS
1
VCO/TX FRQ. ADJ
19
L
L
L
L
2
TX MODE CHECK
19
L
H
L
H
3
TX DATA
19
LL
LL
*1
4
RX SENS.
19
H
L
H
H
5
SQ SENS.
19
L
L
*A
H
6
SINGLE TONE CHECK
19
H
L
L
L
7
DUAL TONE CHECK
19
H
L
L
H
8
DATA IN CHECK
19
L
L
L
H
*2
9
CHANNEL DATA CHECK
19
H
L
L
L
10
DUPLEX
19
L
H
H
H
-- 4 --
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 "CH" 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, or press the "TALK" key.
STEP
FUNCTION
KEY
START CH TX CONT
SC
TX MUTE RX MUTE
CONV
REMARKS
1
VCO/TX FREQ. ADJ
1
21
L
H
H
L
H
2
TX MOD. CHECK
2
21
L
H
L
L
L
3TX DATA
3
21
L
H
L
L
L
*1
4
RX SENS
4
21
H
H
L
H
L
5
SQ SENS
5
21
LH
L*A
L
6
RECEIVE DATA CHECK
6
21
L
H
L
L
H
*2
7
BELL
7
21
H
L
L
L
H
*3
8
BATTERY LOW CHECK
8
21
H
L
L
L
H
*4
9
CHARGE CHECK
9
21
H
L
L
L
H
*5
10
DUPLEX
0
21
L
H
H
H
L
*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 (1kHz) 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 (1kHz) rings when P_BATLOW is "L".
*5 : In the TEST mode 9, bell rings when P_CHRGIN is "L".
Channel rotation
21
20 19 40 1 2 3 4 5 . . . . . . . . 37 38 39 40