Denon AVR-4520, Service Manual

Page: 67 / 281

67
3.5. Errors checking mode (Displaying the protection history)
3.5.1. Specifications
Error mode (Displaying the protection history):
When the set is started up in this mode, the error information is displayed.
3.5.2. About the display on the FL display
When the "STATUS" button is pressed after setting the error (protection history display) mode is set, a history like the one
shown below is displayed, depending on the conditions.
(1) Normal (when there has been no protection incident)
Upper
P R O T E C T H I S T O R Y
Lower
: N O P R O T E C T
(2) For ASO (when the last protection incident was ASO protection)
Upper
P R O T E C T H I S T O R Y
Lower
: A S O
Cause:
The line between speaker terminals is shorted, or speakers with impedance of less than the rated value.
Supplementary information:
As the excess current is detected after operation of the speaker relay, a short on the
speaker terminal and the connected speaker can be identified.
If the power is turned on without correcting the abnormality, the protection function will work about 7 seconds later
and the power supply will be shut off.
(3) For DC (when the last protection incident was DC protection)
Upper
P R O T E C T H I S T O R Y
Lower
: D C
Cause:
DC output of the power amplifier is abnormal.
If the power is turned on without correcting the abnormality, the protection function will work about 7 seconds later
and the power supply will be shut off.
(4) For THERMAL (when the last protection incident was THERMAL protection)
Upper
P R O T E C T H I S T O R Y
Lower
: T H E R M A L *
z
: A, B
Cause: The temperature of the heat sink is excessive.
If the power is turned on without correcting the abnormality, the protection function will work about 7 seconds later
and the power supply will be shut off.
(5) For CURRENT (when the last protection incident was CUIRRENT protection)
Upper
P R O T E C T H I S T O R Y
Lower
C U R R E N T
Cause: Continuous and abnormal output is detected while using speakers with multiple channels.
If the power is turned on without correcting the abnormality, the protection function will work about 1 minute later and
the power supply will be shut off.
b
Additional causes of protection can be due to loose connections, associated components, Microprocessor, etc.
When the "STATUS" button is pressed again after the above protection history as shown above is displayed, the normal
display reappears.(Refer to "PROTECTION DIAGRAM" 33 page.)