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Check the SPI communication line. (DSP1)
YES
Check item(29).
Check the SPI communication line :
Check the CPU.
Is the "SPI" waveform of the TP near the DSP [IC251] correct (like
the one shown in the diagram) when the power is turned on?
3 pin CLK
4 pin MOSI
6 pin CS
5 pin MISO
IC251
YES
NO
Check item(30).
Check the SPI communication line :
Check DSP [IC251], CPU[IC151] patterns as well as soldering.
If there is no problem, go to the next step.
DSP [IC251] is faulty.
Replace with a new device.
Recheck from
check item (1).
If it does not work, replace the PCB.
*The diagram shows an example.
(Signal patterns vary depending on the tim-
ing.)
Points for checking waveforms
- Crest value (3.3V normally)
- Signal change
- CLOCK frequency (about 1.2MHz)
Voltage scale : 2.0V/div
Time scale : 2us/div
116
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