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TROUBLESHOOTING GUIDE
KX-F680BX/KX-F2681BX
49.92 MHz MODEM CLK
(pin 76 of MODEM:IC5)
• This point is
1
/
2
the MHz of the
MODEM CLK 24.96MHz.
(4) RESET
RESET signal makes system initial state just after power on.
If RESET signal is defect, please check IC4, IC5 and components that is connected to these ICs.
(3) OSCILLATOR (CLK)
SYSTEM CLK: 24 MHz, MODEM CLK: 49.92 MHz
5v
5v
Check reset voltage 5v?
power on
(pin 101of IC1 : ASIC)
NG
NG
4.3msec
reset time apx. 175msec
This wave form means another problem, it is not caused by RESET circuit
Please see the item : "CHECK WAVE FORM"
0v
power line 5V
RESET
24 MHz SYSTEM CLK
(pin 96 of ASIC:IC1)
• This point is
1
/
2
the MHz of the
SYSTEM CLK 12MHz.
5V
0V
50 nsec/div
5V
0V
50 nsec/div
Summary of Contents for KX-F680BX
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Page 130: ... 165 KX F680BX KX F2681BX EC1 EC2 EC3 EC4 EC5 EC6 EC7 EC9 EC10 EC11 EC12 EC13 EC8 TOOLS ...
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