Zippy MRW-6420P - Manual (Page 13)

The individual LEDs (both on the rear side or on the front control panel)
indicating the power supply’s status will not light. Meanwhile, the other power
module will continue to backup the power output without affecting the
computer system’s operation or cause system shut-down.
The warning buzzer will continue sound until the user reset the warning buzzer
by pressing the buzzer reset or use the reset switch. The buzzer reset switch can
be connected by wires lead provided by the power supply system (please refer
to Sec. 1.11) and found on the front control panel of the system chassis.
After inserting the power module that is removed for testing earlier, the sound
of the warning buzzer will disappear and the external warning LED will turn
Green again. The individual LED indicating the status of the power supply will
light again. Then, test the other power module by performing the same
procedure of the above.
If you use the power detective signal, there are two/three pins connector (refer
to Sec. 1.9), it should be connected to the card properly.
If everything works fine, then turn off (remote off) the power system.
You can then put back the cover of the case and tighten it with the screws.
Now you have completed the testing and installation of MRT/MRW redundant
power supply system.
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