Panasonic KX-FT25LA Service Manual ▷ View online
The signal lines that must be normal for the system to boot up are listed here [List 1].
For signal lines other than these, even if they malfunction they do not directly affect booting up the system.
For signal lines other than these, even if they malfunction they do not directly affect booting up the system.
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Normal Wave Patterns
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For these reasons and the software sequence to boot up the unit, if you use an oscilloscope to judge whether a signal is OK or NG,
you must check in the same order as in [List 1]. (If the ASIC (CPU) failed to access the ROM, the ASIC cannot access the SRAM
normally.)
you must check in the same order as in [List 1]. (If the ASIC (CPU) failed to access the ROM, the ASIC cannot access the SRAM
normally.)
The digital circuit actually operates according to the timing combinations of these signals. So, if the timing of these signals is even
slightly off, the circuit will not operate normally. Even of the IC did malfunction, the output voltage level may become abnormal but
the timing is accurate according to the specifications. (If oscillation is provided accurately.)
Accordingly, the problem presented here is whether each IC outputs the correct signal. (See the I/O and Pin No. diagram.) In other
words, is it constantly switching between 5V or 3.3V (H) and 0V (L) as described earlier.
slightly off, the circuit will not operate normally. Even of the IC did malfunction, the output voltage level may become abnormal but
the timing is accurate according to the specifications. (If oscillation is provided accurately.)
Accordingly, the problem presented here is whether each IC outputs the correct signal. (See the I/O and Pin No. diagram.) In other
words, is it constantly switching between 5V or 3.3V (H) and 0V (L) as described earlier.
I/O and Pin No. Diagram
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