Panasonic KX-F910BX Service Manual page 61

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
W2 5µs/div
Length
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
Time
Time Base
Internal
CH1 5V/div
CH2 5V/div
CH3 5V/div
CH4 5V/div
W1 2µs/div
Length
W2 5µs/div
Length
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
Time
Time Base
Internal
Trigger
H1 W1
A0
10.0V
1k
1k
D0
ROMCS
SRAMCS
-40.0V
1347.40µs
Roll
Off
H1 W1
A0
10.0V
400
1k
D0
ROMCS
SRAMCS
-40.0V
1362.40µs
Roll
Off
CH1/2 MEM1 MEM2
1397.40µs
1382.40µs
| 65 |
KX-F910BX
Time/div
W1 5µs
W2 5µs
Position
W1 1347.40µs
W2 25.10µs
Time Base
Internal
External
NG
Like clock
Time/div
W1 2µs
W2 5µs
Position
W1 1362.40µs
W2 25.10µs
Time Base
Internal
External
OK