See link for users manual. Instructions for Processor Reset are on page 50.
"Processor Reset
In the rare case where the unit's operation or the displays
seem abnormal, the cause may involve the erratic
operation of the system's memory or microprocessor.
To correct this problem, first unplug the unit from the
AC wall outlet and wait at least three minutes. After the
pause, reconnect the AC power cord and check the
unit's operation. If the system still malfunctions, a
system reset may clear the problem.
To clear the AVR 630's entire system memory including
tuner presets, output level settings, delay times and
speaker configuration data, first put the unit in Standby
by pressing the Standby/On Switch1. Next, press
and hold the Surround Mode Group Selector2
and the Tuning Mode Selector8buttons for three
seconds.
The unit will turn on automatically and display the
RESET message in the Upper Display Line #.
NOTE: Resetting the processor will erase any configuration
settings you have made for speakers, output
levels, surround modes, digital input assignments as
well as the tuner presets. After a reset the unit will be
returned to the factory presets, and all settings for
these items must be reentered.
If the system is still operating incorrectly, there may
have been an electronic discharge or severe AC line
interference that has corrupted the memory or
microprocessor.
If these steps do not solve the problem, consult an
authorized Harman Kardon service center."
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