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B A T T E R Y
OPERATION
Battery Supply
The M 6 7 is designed so t h a t
it
may be operated with
an external b a t t e r y or well filtered
DC
supply pro-
viding 30 Volts DC. Current drain is under 6 ma. a t
+
I 0 d b m output level.
The
DC
input terminals are located adiacent t o the
power cord on the rear panel and are designated "30
Volts
DC"
"
-I-"
and
"-".
The use o f b a t t e r y supplies designed f o r the M 6 7 (see
Accessory List) i s recommended b o t h f o r convenience
in connecting and mounting and t o p e r m i t use o f the
automatic power change-over feature.
Automatic Power Change-Over
W h e n used with Shure accessory power supplies, t h e
M 6 7 m a y b e operated f r o m t h e
AC
power line with t h e
b a t t e r y supply connected. I n this configuration, the unit
will automatically switch t o b a t t e r y operation should
AC
voltage fall below a suitable level. This change-over
is completely automatic, instantaneous, a n d completely
noiseless. Should line power fail completely, t h e
VU
meter lamps will extinguish, providing a visual indica-
t i o n o f t h e line failure.
If
use o f a 30-volt
DC
supply
other than Shure
Battery Supplies
i s
desired, t h e
automatic change-over feature may b e retained b y
connecting a suitable silicon diode (Shure
RKCPI)
i n series with t h e positive lead.
The cathode (band)
e n d connects t o t h e +30-Volt
DC
terminal.
Battery Check
Battery condition may b e determined
by
use o f t h e
"Battery Check" position o f the main power switch
adjacent t o t h e
VU
meter. This check must b e made
with the
AC
line c o r d disconnected. The check pro-
cedure is as follows:
With
the
AC
line c o r d disconnected, leave power
switch in
"ON"
position f o r a t least ten seconds
( t o discharge filter capacitors), then move switch
u p t o "Battery
Check."
Observe reading on
VU
meter.
A
new b a t t e r y will give a b o u t a + 2 V U Indi-
cation. Battery condition is g o o d
if
meter indica-
tion is above
0
VU
(red end o f scale). 0 V U or below
indicates t h a t b a t t e r y must be replaced f o r proper
operation.
For
best
performance
on
b a t t e r y operation
a t
temperatures below
40"
F.,
change batteries when
Battery Check meter reading is I
.O
V U or lower.
NOTE:
This check interrupts power t o t h e ampli-
fiers, and therefore, should b e made only
when t h e unit is n o t in operation.
D C Power Take-Off
With AC
operation, t h e "30-Volt
DC"
terminals are
energized with polarity shown and may b e used t o
power u p t o t w o additional M67's o r other 30-volt
DC
low drain accessories.
ACCESSORIES
A67B Battery Supply
This unit is designed t o power t h e
M67
a t
full
r a t e d
output. Battery life is approximately 7 0 hrs a t
+
10
d b m and 85 hrs a t
+4
d b m o u t p u t a t
4
hours use
per day. See temperature note below.
It
may b e used either as the sole power source o r as
a stand-by safety during
AC
operation, providing
automatic, noiseless switchover in case o f
AC
failure.
The housing i s designed t o attach t o the M 6 7 as
shown in Figure
C,
and i s attached b y removing one
o f the M 6 7 cover screws, positioning the b a t t e r y
supply over the hole, and fastening the t w o together
with the screw.
The b a t t e r y complement
i s
three Eveready
2
16's or
equivalent 9-volt batteries.
Earlier models o f the A67B had a b a t t e r y complement
o f three Burgess U201s, Eveready 413's o r equivalent
30-volt battery.
N O T E : Due t o changes in the operating characteristics
o f carbon-zinc batteries a t low temperatures,
the useful operating life will be noticeably
shorter a t lower than normal room tempera-
tures. See Battery Check Instructions.
A67B INSTALLATION
FIGURE C
A 6 7 H HandleiTilt Stand
The M o d e l A 6 7 H i s designed t o provide a convenient
means f o r tilting the M 6 7 t o permit better panel
visibility and greater ease o f operation. In the locked
position the front panel
i s
elevated 20".
In the free
position, the A 6 7 H serves as a r u g g e d carrying handle.
A68P Phono-Preamplifier
The A68P is a monaural pre-amp which may be used
t o convert the bridging line i n p u t o f the M 6 7 f o r use
as an equalized phono input.
It
provides b o t h equali-
zation and preamplification, and is powered f r o m t h e
30-volt D C power take-off
provision. (The A68P is
supplied with a phono plug which must b e replaced
with a Cannon XL3-I2 t y p e connector. Pin
3
center
conductor, pins
2
and
I
shield)
A68S Sfacking Kit
This accessory consists o f brackets f o r vertical stacking
o f t w o M67's, and the interconnecting cable f o r t h e
mix bus connections.
A68R Rack Panel Kit
This
k i t
consisis o f a 19"x31/2" precut rack panel and
necessary hardware f o r rack mounting o f t h e M 6 7
with its cover in place.
A68L Locking Panel
This panel fits within the front hood o f t h e M 6 7 cover
and locks in place t o prevent tampering with t h e f r o n t
panel controls.
A C 6 0 ~ t t a c h : Carrying Case
This
case is compartmentalized
and foam lined f o r
an M 6 7 and accessories.
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