Trouble Shooting - Pioneer XV-DV55 Service Manual

7.1.5 TROUBLE SHOOTING

XV-DV55 microcomputer troubleshooting
Symptom of problem
• The power supply does not enter .
• The standby LED lights even if the
POWER key is pushed.
• It enters the state of POWER OFF
soon even in case of the POWER
ON.
• DVD does not operate at all.
• Time is not displayed in FL DISPLAY
at the DVD function.
• The operation key is not accepted at
all.
Thought cause
• The microcomputer is not reset.
• The AC pulse is not input.
• The oscillation circuit of the microcomputer
does not oscillate.
• If the function is DVD, the 3.3DETECT input
is 2.9V or less.
• It does not communicate with the DVD
microcomputer.
• It is recognized that other KEY has already
been pushed.
Check method
• Whether terminal RESET (12Pin) is "H" is confirmed.
The operation of the RESET circuit is confirmed if
not becoming "H".
• Whether the AC pulse is input to AC input terminal
(11Pin) is confirmed. If the AC pulse is not input,
the AC pulse generation circuit is confirmed.
• The microcomputer or the oscillation circuit is broken.
The microcomputer or the oscillation circuit is
exchanged.
• If the voltage of the 3.3DETECT (13Pin) terminal of
the microcomputer is 2.9V or less, the voltage is
adjusted to 2.9V or more.
• Whether terminal (27Pin, 78Pin, 98-100Pin) for the
communication with the DVD microcomputer does
the communication operation is confirmed. If the
communication operation is not done, whether the
B to B connector etc. are disconnected is confirmed.
• Whether "H" is output to terminal DVDRESET
(87Pin) is confirmed.
• When KEY is not pushed, whether KEY input
terminal (18Pin) is 5V is confirmed. If the KEY input
terminal is not 5V, whether KEY SW on the line
breaks is confirmed.
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