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SERVICE MANUAL
PUBLISHED IN JAPAN, Jun., 1998
FILE NO. 2B0-9801
FT-8258
CORDLESS TELEPHONE


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-- 1 --
CONTENTS
SAFETY PRECAUTIONS ...................................................................................................................... 1
OPERATING CONTROLS ..................................................................................................................... 2
ALIGNMENT PROCEDURE .................................................................................................................. 3
BLOCK DIAGRAMS ............................................................................................................................... 9
SCHEMATIC DIAGRAMS .................................................................................................................... 14
TROUBLESHOOTING HINTS ............................................................................................................. 24
IC AND TRANSISTOR VOLTAGE CHART ......................................................................................... 31
SEMICONDUCTOR LEAD IDENTIFICATION ..................................................................................... 38
ELECTRICAL PARTS LOCATION ...................................................................................................... 42
WIRING DIAGRAMS ........................................................................................................................... 47
EXPLODED VIEW AND MECHANICAL PARTS LIST ........................................................................ 49
PARTS LIST ........................................................................................................................................ 53
ASSEMBLY PARTS LIST .................................................................................................................... 75
SPECIFICATIONS ............................................................................................................................... 76
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.


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-- 2 --
OPERATING CONTROLS
12
3
45
6
78
9
0#
ABC
DEF
JKL
MNO
GHI
TUV
WX
PQ
RS
YZ
TONE
OPER
FLASH/RDL
INTCOM
CH
VOL/RING
TALK
12
3
45
6
78
9
0
#
ABC
DEF
JKL
MNO
GHI
TUV
WX
PQ
RS
YZ
TONE
OPER
FLASH/RDL
CHARGE
POWER
SPEAKER
INTCOM
MUTE
PAUSE
PRIVACY
MEM
1
2
900MHZ
Charging Contacts
TALK button
TALK/BATT LOW LED (Red)
· Lights when the handset is used for
a phone conversation on line 2.
· Blinks when the base unit or
additional phone is in use on line 2.
· Blinks when line 2 is put on hold.
· Blinks when line 2 is ringing.
TONE button
FLASH/RDL (Flash/Redial) button
MEM (Memory) button
PAUSE button
LINE 2 LED (Orange)
INTCOM
button
Dialpad (1~9,
and # Dial Buttons)
HOLD
button
CH (Channel) button
LINE 1 button
LINE 2 button
VOL/RING
(Volume/Ringer volume) button
CONF
(Conference) button
SPEED DIAL INDEX (back)
Battery compartment (back)
LINE 1 LED (Green)
· Lights when the handset is used for
a phone conversation on line 1.
· Blinks when the base unit or
additional phone is in use on line 1.
· Blinks when line 1 is put on hold.
· Blinks when line 1 is ringing.
· Standby status : OFF
· Lights ON during a phone
conversation using the handset.
· Blinks when a channel is changed,
and during the low battery status
and mute status.
· Lights when the base unit is used
as speaker phone on line 1.
· Blinks when the handset or
additional phone is in use on
line 1.
· Blinks when line 1 is put on hold.
· Blinks when line 1 is ringing.
· Lights when the base unit is used
for a phone conversation on line 2.
· Blinks when the handset or
additional phone is in use on
line 2.
· Blinks when line 2 is put on hold.
· Blinks when line 2 is ringing.
TEL LINE 1/2 jack
TEL LINE 2 jack
DC IN 9V jack
Tone/Pulse switch
Line 1 ringer
volume switch
Antenna
SPEAKER volume control
Speaker
One-touch dialing keys
(1 to 8)
MEM (Memory) button
PAUSE button
MUTE button
INTCOM LED (Green)
SPEAKER button
SPEAKER LED (Green)
SPEED DIAL INDEX
Microphone
LINE 2 LED (Orange)
LINE 1 LED (Green)
LINE 2 button
CHARGE LED
POWER LED
TONE button
LINE 1 button
FLASH/RDL
(Flash/Redial) button
INTCOM button
Line 2 ringer
volume switch
CONF (Conference)
button
HOLD button
· Pull out the SPEED DIAL INDEX
card to find out a destination name
associated with a number preset
in the speed dial memory.
MEM
PAUSE
PRIVACY
12
Antenna
Dialpad (1~9,
and #
Dial Buttons)
BASE UNIT CONTROLS
HANDSET CONTROLS


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-- 3 --
ALIGNMENT PROCEDURE
Test Mode For Base Unit
Press the " " and "#" keys at the same time about 1.5 seconds while turning the power on, the confirmation beep will
sound to indicate that the unit is in the test mode.
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 the "FLASH/RDL" key, but if changing the step, the channel returns to the
start channel.
3. To cancel Test mode:
Bell rings, charge the Handset, or press the "SPEAKER" key.
*1 : Switch the line with LINE1, LINE2, and CONF keys, the corresponding LED lights.
*2 : "0000..." (250Hz) will be fed out continuously as transmitting data.
*3 : INTCOM LED lights when sensing SQ.
*4 : INTCOM LED lights when detecting BELL.
*5 : INTCOM LED lights when the received data are "0000..." (250Hz).
(In the case of Dual Tone, changes as 1
2 3 4 5 6 7 8 9 0 * # 1.)
*6 : Charge LED lights when detecting Charge ON.
*7 : Every pushing of PAUSE key makes tone change.
DTMF Frequency
ROW1
:
697
ROW2
:
770
ROW3
:
852
ROW4
:
941
COL1
:
1209
COL2
:
1336
COL3
:
1477
*8 : RX Mute turns on or off when pushing MUTE key. (Off initially, on when pushed.)
*9 : LINE LED lights as follows according to the condition of the telephone used together.
ON Hook
:
ON
OFF Hook
:
Blinking
No Connection
:
OFF
Channel rotation
19
20 21 40 1 2 3 4 5 . . . . . . . . 37 38 39 40
S
T
E
P
FUNCTION
K
E
Y
S
T
A
R
T
C
H
T
X
P
W
R
T
X
M
U
T
E
R
X
M
U
T
E
R
L
C
N
T
1
R
L
C
N
T
2
C
T
1
P
A
S
C
T
2
P
A
S
S
P
1
P
A
S
S
P
2
P
A
S
I
N
T
P
A
S
C
N
F
P
A
S
D
T
M
F
L
1
D
T
M
F
L
2
D
T
M
F
S
P
D
T
M
F
E
N
S
P
K
C
S
S
P
K
A
M
P
M
I
C
M
U
T
E
R
E
M
A
R
K
S
1
VCO/TX FRQ. ADJ
1
19
LL
L
LLL
LLL
L
LLL
LL
H
H
H
TX CHECK L1
L
H
L
H
L
H
LLL
L
LLL
LL
H
H
H
TX CHECK L2
L
H
L
L
H
L
H
L
L
L
L
L
L
L
L
H
H
H
2
TX CHECK L1 + L2
219
L
H
L
H
H
H
H
LL
L
H
LL
LL
H
H
H
*1
3
TX DATA
3
19
L
L
L
LLL
LLL
L
LLL
LL
H
H
H
*2
RX SENS L1
H
L
H
H
L
H
LLL
L
LLL
LL
H
H
H
RX SENS L2
H
L
H
L
H
L
H
L
L
L
L
L
L
L
L
H
H
H
4
RX SENS L1 + L2
419
H
L
H
H
H
H
H
LL
L
H
LL
LL
H
H
H
*1
5
SQ SENS
5
19
LL
H/L H
L
H
LLL
L
LLL
LL
H
H
H
*3
6
BELL MODULATION
6
19
L
H
L
H
L
H
LLL
L
LLL
LL
H
H
H
7
RINGER CHECK
7
19
H
L
L
LLL
LLL
L
LLL
LL
H
H
H
*4
8
DATA IN CHECK
8
19
L
L
H
H
L
H
LLL
L
LLL
LL
H
H
H
*5
9
CHANNEL DATA
9
19
H
L
L
LLL
LLL
L
LLL
LL
H
H
H
*6
DUPLEX L1
L
H
H
H
L
H
LLL
L
LLL
LL
H
H
H
DUPLEX L2
L
H
H
L
H
L
H
L
L
L
LLL
LL
H
H
H
10
DUPLEX L1 + L2
019
L
H
H
H
H
H
H
LL
L
H
LL
LL
H
H
H
*1
DUAL TONE L1
H
L
L
H
L
L
L
L
L
L
L
H
L
L
H
H
H
H
*1
11
DUAL TONE L2
MEM 19
H
L
L
L
H
L
L
L
LLL
L
H
L
H
H
H
H
*7
12
INTERCOM
HOLD 19
L
H H/L
LLL
LLL
H
LLL
LLL
LL
*8
13
ON HOOK PARA
INT'C 19
H
H
L
LLL
LLL
L
LLL
LL
H
H
H
*9


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-- 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 PWR RX PWR 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
HL
HL
5SQ SENS
5
21
L
H
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