Panasonic KX-TS85GB / KX-TS85GW Service Manual ▷ View online
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25
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KX-TS85GB/KX-TS85GW
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HANDSET CIRCUIT AND HEADSET CIRCUIT
1) Transmission Signal Path
The input signal from the microphone passes through:
MIC Pin 8 and 10 IC1
The input signal from the microphone passes through:
MIC Pin 8 and 10 IC1
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Pin 12 of IC1
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Interface (Q6)
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R18
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Telephone Line.
2) Reception Signal Path
Signals received from the telephone line pass through:
Telephone Line
Signals received from the telephone line pass through:
Telephone Line
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C22
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Pin 15 of IC1
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Pin 21 of IC1
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Speaker.
Circuit Diagram
R18
C22
R19
Q6
R41
C32
C28
R43
C33
C34
CS
IC1
RI
RO
M1 M2
12
15
21
8
10
R32
C27
Headset SP
H/S SP
H/S SP
Headset GND
If headset is plugged in, the base
unit becomes headset mode.
R42
Headset MIC
H/S SP
Headset GND
H/S MIC
C50
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KX-TS85GB/KX-TS85GW
1. SERVICE HINTS
2. PULSE DIALING PROBLEMS
TROUBLE SHOOTING GUIDE
SYMPTOM
CURE
Pulse will not dial.
No pulse, can hear dialing but no number output.
Rings, no dial tone, can't dial out, no audio circuit, dead.
No dial tone on Handset.
Memory does not work.
Unit rings, has dial tone, memory does not work.
Rings but can't answer.
Doesn't dial.
Dead.
Rings, no dial tone, no pulse or tone dial.
No rings.
No volume Handset.
Buttons stick under upper cabinet assembly. From key board.
No pulse dial.
Check Q3 and Q4. Check "DIALING MODE"
Check IC1. Check "DIALING MODE"
Check IC1.
Check Q3, Q4 and IC1.
Check IC2.
Check IC2
.
Check S1.
Check IC1.
Check IC1.
Check Q3 and Q4, D4.
Check C1, C2, R1, R2, R4 D1, Q1, Q2 and IC1.
Check IC1 and IC2.
Adjust the setting of buttons.
Check Q3, Q4 and Q6. Check "DIALING MODE"
Chack
" DIALING MODE "
pulse sound be
monitored?
" DIALING MODE "
pulse sound be
monitored?
Does the voltage across
Tip (T) and Ring (R)
rapidly switch between
48 V and 10V?
Tip (T) and Ring (R)
rapidly switch between
48 V and 10V?
Check Q3, Q4, D4
and ZNR2.
and ZNR2.
Do pulses (0.6 Vp-p)
appear at the base of
Q3?
appear at the base of
Q3?
Does Pin 2 of IC1
output the dial pulse?
output the dial pulse?
Check D4, Q3, Q4
and ZNR2.
and ZNR2.
Check Q6.
Check IC1, and
Key matrix and
connection FFC cable.
Key matrix and
connection FFC cable.
Check IC1
X1 and C19.
X1 and C19.
NO
NO
YES
YES
YES
YES
NO
NO
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KX-TS85GB/KX-TS85GW
3. PROBLEMS WITH THE HANDSET
4. TONE DIALING PROBLEMS
NO
NO
NO
NO
NO
YES
YES
YES
YES
YES
NO
Connect to the
Telephone line and
lift the Handset.
Telephone line and
lift the Handset.
Can a dial tone be
heard from the
handset?
heard from the
handset?
Can signals be
transmitted from
the handset?
transmitted from
the handset?
Is there a dial tone
at pin 15 of IC1?
at pin 15 of IC1?
Is there a dial
tone at pin 21
of IC1?
tone at pin 21
of IC1?
Check the handset,
handset cord,
C28 and R32.
handset cord,
C28 and R32.
Does a signal
appear at pin 12 of
IC1?
appear at pin 12 of
IC1?
Does a signal
appear at pin
8, 10?
appear at pin
8, 10?
Check Q3, D4, Q4,
Q6, R18 and ZNR2.
Q6, R18 and ZNR2.
Check, Handset MIC
and Handset cord.
and Handset cord.
Check IC1.
Check IC1.
Check Q3, D4
Q4, C22 and
ZNR2.
Q4, C22 and
ZNR2.
OK
Check IC1.
Check D4 and
ZNR2.
ZNR2.
Check IC1 and key
matrix and connection
FFC cable.
matrix and connection
FFC cable.
YES
YES
YES
YES
NO
NO
NO
NO
Check "DIALING MODE"
Program is TONE.
Can the DTMF sound
be monitored?
Program is TONE.
Can the DTMF sound
be monitored?
Does a DTMF signal
appear at Pin 12 of
IC1?
appear at Pin 12 of
IC1?
Does a DTMF signal
appear at emitter of
Q4?
appear at emitter of
Q4?
Check Q3, Q4, R18.
Are the DTMF signals
composed of 2
frequencies?
composed of 2
frequencies?
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KX-TS85GB/KX-TS85GW
5. HOW TO CHECK THE IC1
Connect to the telephone
line and lift the handset.
Push and hold the key "0~9".
line and lift the handset.
Push and hold the key "0~9".
Is the voltage at pin 34~36
of IC1?
of IC1?
Is the voltage at pin
22 of IC1 3~5V?
22 of IC1 3~5V?
Is the D4, Q3, Q4,
S1 and ZNR2.
S1 and ZNR2.
Does the signal at pin
33 of IC1 3.58MHz
oscillate?
33 of IC1 3.58MHz
oscillate?
END
Check the solded pin
37~40 of IC1, all
keys and connection
of FFC cable.
37~40 of IC1, all
keys and connection
of FFC cable.
Check the contact
of key.
of key.
Check IC1.
Is there voltage output from
any of the pins 37 to 40 of
IC1 when any key is pressed
as shown below.
any of the pins 37 to 40 of
IC1 when any key is pressed
as shown below.
When the signals are output from
more than one pin of 37 to 40 of IC1.
more than one pin of 37 to 40 of IC1.
NO
NO
NO
NO
YES
YES
YES
YES
4~5 V
0 V
4 V
0 V
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