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109

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 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 3.3V (H) and 0V (L) as described earlier.

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111

After the power is turned on, the ASIC initializes and checks each IC.
The ROM, DRAM, and modem are checked.
If initialization fails for the ICs, the system will not boot up.
In this case, please find the cause as follows.

NG Example (P.113)
Power Supply Board Section (P.119)

112

Refer to Translation Lists (P.10) for display.