Denon AVR-X3500H Service Manual page 110

Check the communication line.
YES
Check item(3-9.4.). Check the communication line :
Check the CPU.
Is the waveform of the TP near the DIR [U1040] correct (like the one
shown in the diagram) when the power is turned on?
CLK
MOSI
U1040
CS
MISO
YES NO
Check item(3-9.5.). Check the communication line :
Check DIR [U1040], CPU [U1018] patterns as well as soldering.
If there is no problem, go to the next step.
DIR [U1040] 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 tim-
ing.)
Points for checking waveforms
- Crest value (3.3V normally)
- Signal change
- CLOCK frequency (about 2MHz)
Voltage scale : 2.0V/div
Time scale : 2us/div
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