The Pw4000 Power Supply - Yamaha PM4000 Operating Manual

2.4 The PW4000 Power Supply

141. POWER
This alternate-action switch turns on the AC input
to the supply, and thereby provides the necessary
output voltages to the console via the umbilical
power cable. Pressing the switch a second time
turns off the power.
142. Operation Monitor
This panel of LEDs indicates when power is
present at the various power supply outputs,
as well as other aspects of the power supply's
operation. A row of NORMAL LEDs is illuminated
when +48V, +12V, +19V, and -19V outputs are
operating. Below that is a corresponding row of
UNUSUAL LEDs, one or more of which
illuminates if the output is not within normal
Figure 2-16. PW4000 Power Supply (Front and Rear Panels)
tolerance. There is also a green POWER indicator
that is illuminated when power is turned on, a red
THERMAL indicator that is illuminated when the
power supply has overheated (and automatically
shut down), and a digital indicator that displays
the AC line voltage input to the power supply.
143. (Grille)
The power supply is cooled by a pair of quiet
running fans that pull air through front-panel
grilles and exhaust it through vents at the back. A
reticulated foam element behind each grille filters
the air entering the power supply.
NOTE: Filter elements are cleanable. Refer to Section 9.
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