Panasonic KX-FP105BX, Service Manual, Page: 94 / 238

Normal Wave Patterns
Remarks:
When you use an oscilloscope to judge whether a signal to be tested is normal or NG, perform the signal check in exactly the
same order as in [List 1]. (If the ASIC fails to access the ROM, the ASIC cannot access SRAM or DRAM normally.)
The digital circuit actually operates according to the timing combinations of these signals. If the timing of these signals is even
slightly delayed, the circuit will not work. Nor will it if the IC is defective and the output voltage level is not normal although the timing
of these signals is accurate enough to meet the specifications. (Make sure that your oscilloscope is calibrated before starting a
test.)
Therefore, it is imperative to confirm whether each IC outputs the signal at the correct level. (See the I/O Pin No. Diagram.) The
signal level should be constantly output at between 5V (H) and 0V (L) as described earlier.
Note:
Simply check the output level and make sure if the IC repeatedly outputs the signal at between 5V (H) and 0V (L).
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