Panasonic KX-F900 Service Manual page 64

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KX-Fg00
The graphs below show you the wave form that is observed when MODEM doesn't work. (Oscillation is not intentionally
supplied to MDM.)
Please compare OK form to NG form.
MDMCS (pin 54 of ICl 1) signal is coming many times more than good wave form.
In the case of this wave form MODEM doesn't work. If soldering, conductance is no problem, we need to replace MODEM
(IC11).
CH1 5V/div
CH2 5V/div
CH3 5V/div
CH4 5V/div
Wl 5ps/div
Length 1k
W2 511s/div
^ Length 1k
_ampJing Normal
20Msps
Marker 1
vT 3520951i_
Marker 2
T
V
z_T
l/AT
AV
H1 W1
I0.0V_
fTrigger _CH1/2 z_MEM1AMEM2 Time/div
Wl
A0
DO
_o% ROMCS
-345.451is _ 2.895k Hz
4.8 V
! MDI£1CS i ! i i
: ,,,
Time
Time Base ] Roll
l off
I I
Time Base
External
NG
many MDMCS
CH1 5V/div
CH2 5V/div
CH3 5V/div
CH4 5V/div
Wl
W2
S Lengtl
ampling
Normal
20Msps
Marker 1
vT _%.9_
Marker 2
Tv 75_°_v
AT -345.45pS
l/aT
2.895kHz
AV 4.8 V
Time
Time Base
H1 Wl
10.0V
A0
DO
i : i i i
! MDMCS ! :
................. iz0°.many__
-40.0V
1347.40#s i ; 1397_.40#s I
I I
Time/div
Wl
Wl_
Time Base
External
NG
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