Marantz NR1200 Service Manual page 86

Check the SPI communication line.
YES
Check item(3-5.4.). Check the SPI communication line :
Check the CPU.
Is the "SPI" waveform of the TP near the DSP [U1021] correct (like
the one shown in the diagram) when the power is turned on?
D_CK 3pin
D_MOSI 4pin
D_CS 6pin
U1021
D_MISO 5pin
YES NO
Check item(3-5.5.). Check the SPI communication line :
Check DSP [U1021], CPU[U1013] patterns as well as soldering.
If there is no problem, go to the next step.
DSP [U1021] is faulty.
Replace with a new device.
Recheck from check item (3.1.).
If it does not work, replace the PCB.
*The diagram shows an example.
(Signal patterns vary depending on the
timing.)
Points for checking waveforms
- Crest value (3.3V normally)
- Signal change
- CLOCK frequency (about 6MHz)
Voltage scale：2.0V/div
Time scale：2us/div
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