Pioneer PRO-141FD Service Manual page 85

5
[3] PROCESSING IN ABNORMALITY
Abnormal speaker output
Circuit configuration
I/O Assy
Specifications for port monitoring
Port Name SD/PD Indication
SP_ALM AUDIO
Operation specifications of the main CPU
(1) Establish the short-circuit of the speaker by the main CPU
• A warning indication is displayed 2 seconds after an abnormality occurs, then after another 3 seconds,
a shutdown will be generated. (The blue LED flashes 5 times.)
• A warning indication is displayed for all input-signal types.
• Example of a warning indication: "The speaker terminals are short-circuited. After reconnection, turn the unit on again."
(2) Display conditions
When the panel is on: A warning indication is displayed immediately.
When the panel is off: A warning indication is not displayed immediately but is displayed when the panel is turned on.
Note: A warning indication is displayed each time the panel is turned on if the conditions for a shutdown persist.
A shutdown will not be generated in a case of short-circuiting of the speaker output, because Auto Protection mode
is activated for the audio amp (IC3201) in such a case. If an abnormally high voltage is output from the speaker output
terminals because of a failure in IC3201, etc., a shutdown will be generated.
Conditions for resetting the circuits
The circuits will be reset upon Standby ON/OFF.
5
6
SP_ALM
DIGITAL
POWER
AMP IC
Active
Shutdown occurs when the signal is "L."
30 mS ∗ 3 times
PRO-141FD
6
7
MAIN Assy
3.3V
PULL_U
SP_ALM
Monitoring conditions
RST4 = "H" (always)
The main CPU operations described below will be
(Monitoring starts 2 sec
performed when "SP_ALM: L" is detected (established)
after the above conditions
under the monitoring conditions.
are established.)
7
8
MAIN_UCOM
Operation
8
A
B
C
D
E
F
85