Installation; Power Mains - Yamaha PM-1000 Manual

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INSTALLATION
PLACEMENT OF EQUIPMENT
Recessed mounting details
for 16-channel consoles
A - 33 7/8" (86cm)
B - 33 5/8" (85.5cm)
C - 3" (7.6cm)
POWER MAINS
U.S.A. and Canadian models are designed to operate
with 110-120V AC, 50-60Hz power mains. The console
must be AC grounded for safety and for proper shielding;
a 3-wire power cord is provided for this purpose. If a
3-wire outlet is not available, or if there is any chance
the outlet may not be grounded, a separate jumper wire
must be connected from the console chassis to an earth
ground. Cold water pipes generally provide good grounds,
but hot water pipes, pipes on the user side of a water
meter, or PVC pipes should be avoided. When in doubt,
drive a length of copper pipe into moist earth to obtain
a ground point, burying at least b' (1.5m) of pipe.
Monitor, or any suitable AC voltmeter, the power line
must measure more than 100Vrms and less than
135Vrms.
If power line voltages do not fall within the 100V
to 135V range, a variac or some other device must be
used to correct the voltage. Failure to observe this pre-
caution may damage the console, and will void the
warranty.
A relatively minor power supply modification allows
the use of 220-240V AC mains. Described in Section
Seven of this manual,the modification is to be performed
only by qualified service technicians.
THEORY OF GROUNDING
Careful grounding procedures are essential for proper
operation, not only of the PM-1000, but of the entire
audio system. Many grounding techniques exist, and
certainly there are several ways to achieve a satisfac-
torily grounded audio system. Several books have been
written on the subject. For further information (to com-
plement what we are about to present) consult the fol-
lowing sources: THE AUDIO CYCLOPEDIA by
Howard M. Tremaine (Pub. Howard W. Sams); the
ALTEC ACOUSTA-VOICING MANUAL Ed. by
John M. Eargle & Mark E. Engebretson (Pub. Altec
Corp.); GROUNDING & SHIELDING TECHNIQUES
IN INSTRUMENTATION by Ralph Morrison
(Pub. Wiley).
CAUTION. In any audio system installation, govern-
mental and insurance underwriters' electrical codes must
be observed. These codes are based on safety, and may
vary in different localities; in all cases, local codes take
precedence over any suggestions contained in this manual.
As set forth in the PM-1000 Warranty, Yamaha Inter-
national Corporation shall not be liable for incidental or
consequential damages, including injury to persons or
property, resulting from improper, unsafe or illegal
installation of the PM-1000 or of any related equipment;
neither shall the Corporation be liable for any such dam-
ages arising from defects or damage resulting from
accident, neglect, misuse, modification, mistreatment,
tampering or any act of nature.
The following grounding scheme is presented in the
belief that it is one of the more simple, yet effective
methods available, but by no means is it the only
effective method.
The PM-1000 chassis provides a convenient point
from which all other equipment in the system can
derive its ground. The auxiliary equipment chassis is
first isolated from the AC main ground, if necessary;
then the auxiliary chassis are all grounded to the PM-
1000 chassis via the shields of the interconnecting audio
cables. To insure the success of this scheme, the PM-
1000 chassis must be well grounded either through the
ground lead in its AC cord, or through an earth ground
attached to the console chassis.