Panasonic KX-F680BX - Page 60

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TROUBLESHOOTING GUIDE
KX-F680BX/KX-F2681BX
Below graph show you the wave form that is observed when SRAM doesn't work. (BUS line at SRAM is intentionally
opened.) Please compare OK (under) to NG (upper). SRAMCS (pin 20 of IC3) signal is coming like clock.
In the case of this wave form SRAM access doesn't work. If soldering, conductance is no problem, we need to replace
SRAM (IC3).
CH1 5V/div
CH2 5V/div
CH3 5V/div
CH4 5V/div
W1 5µs/div
Length 1k
W2 5µs/div
Length 1k
Sampling
Normal
20Msps
Marker 1
T 1372.40µs
V 5.0 V
Marker 2
T 7.50µs
V 0.2 V
T -1364.90µs
1/ T
732.7 Hz
V -4.8 V
W1 5µs
W2 5µs
Position
W1 1347.40µs
W2 25.10µs
Time
Time Base Roll
Off
Time Base
External
Internal
Internal
Trigger CH1/2 MEM1 MEM2
-40.0V
1347.40µs 1397.40µs
Time/div
10.0V
H1 W1
A0
D0
ROMCS
SRAMCS
NG
Like clock
CH1 5V/div
CH2 5V/div
CH3 5V/div
CH4 5V/div
W1 2µs/div
Length 400
W2 5µs/div
Length 1k
Sampling
Normal
20Msps
Marker 1
T 1372.40µs
V 5.0 V
Marker 2
T 7.50µs
V 5.0 V
T -1364.90µs
1/ T
732.7 Hz
V 0.0 V
W1 2µs
W2 5µs
Position
W1 1362.40µs
W2 25.10µs
Time
Time Base Roll
Off
Time Base
External
Internal
Internal
-40.0V
1362.40µs 1382.40µs
Time/div
10.0V
H1 W1
A0
D0
ROMCS
SRAMCS
OK