Yamaha HTR-5635 Service Manual page 12

HTR-5635
• Display provided when DIAG started
The FL display of the main unit displays the protection
function history data and the version (1 alphabet) and the
DIAG menu (sub-menu (ANALOG BYPASS) of DIAG
menu No.1 DSP THROUGH) a few seconds later.
When there is no history of protection function:
Opening message
When there is no history
Version (1 alphabet)
of protection function
When there is a history of protection function:
When there is a history of protection
function due to excess current
Cause: An excessive current flowed through the power
amplifier.
Supplementary information: As current of the power
transistor is detected, the abnormal channel can be
identified by checking the current detect transistor.
Turning on the power without correcting the abnormality
will cause the protection function to work immediately and
the power supply will instantly be shut off.
Note)
• Applying the power to a unit without correcting the
abnormality can be dangerous and cause additional
circuit damage.
• The output transistors in each amplifier channel
should be checked for damage before applying any
power.
• Amplifier current should be monitored by measuring
across the emitter resistors for each channel.
When there is a history of protection
function due to an abnormal voltage in
the power supply section
Cause: The voltage in the power supply section is
abnormal.
Supplementary information: The abnormal voltage is
displayed in % based on 5V as 100%.
Turning on the power without correcting the abnormality
will cause the protection function to work 1 second later
and the power supply will be shut off.
12
DIAG menu display
After a few seconds
Version (1 alphabet)
Version (1 alphabet)
Voltage display in %
When there is a history of protection
function due to abnormal DC output
Cause: DC output of the power amplifier is abnormal.
Turning on the power without correcting the abnormality
will cause the protection function to work 3 seconds later
and the power supply will be shut off.
When there is a history of protection
function due to excessive heat sink
temperature
Voltage display in %
Cause: The temperature of the heat sink is excessive.
Supplementary information: The abnormal voltage is
displayed in % based on 5V as 500%.
Turning on the power without correcting the abnormality
will cause the protection function to work 1 second later
and the power supply will be shut off.
* Additional causes of protection can be due to loose
connections, associated components, CPU, etc.
* For the protection voltage value, refer to DIAG menu
No.10 described later.
• History of protection function
When the protection function has worked, its history is
stored in memory with a backup. Even if no abnormality
is noted while servicing the unit, an abnormality which
has occurred previously can be defined as long as the
backup data has been stored.
The history of the protection function is cleared when
DIAG is cancelled by selecting PRESET RESERVED
(Memory initialized) of DIAG menu No.9 or when the
backup data is erased.
Version (1 alphabet)
Version (1 alphabet)