Special Pov,^Rsources; Practical Service Suggestions; Organ Does Not Play; One Key Does Not Play - Hammond M Series Service Manual

EAR PHONE (STEREO)
Stereo ear phones can give pleasing results when attached
as
shown
in the sch-
matic
below. A separate
two
pole double throw switch
is
required
in addition
to
the listed resistors and jack.
Use
of
good quality ear phones made by David
Clark, Koss,
or
Telex
are
recommended and
can be secured from any parts supply
house.
GN.
T^J
Organ
Spk,
wires
BLK,
CN, ©-
Rev, Spk. wires
BLK-
*
£:-3
100
-a
10
jo.
10
W
SPECIAL POWER SOURCES
The organ must always be connected
to an alternating current source
of the
voltage and frequency specified
on the name
plate.
If the only available power
source
is
direct current
or has
a
frequency different from
that specified,
it
will
be necessary
to
provide
a
converter
or motor generator
of at least 170
watts capacity.
PRACTICAL SERVICE SUGGESTIONS
ORGAN DOES NOT PLAY
(a)
If the starting motor does not operate when
the
"Start" switch
is pressed
and If the tubes
do not light
with
the'^Run''
switch
on, check
the
power
wiring, power switch, line cord, line cord plug,
and wall outlet.
(b)
If the generator turns and
the tubes light, but no
sound can be obtained
with
all controls in
playing position,
the most likely source
of
trouble
is the
amplifier.
In
most respects
this
is a
conventional amplifier
circuit, and
the
schematic diagrams will enable
the
service man
to
lo-
cate the trouble.
ONE KEY DOES NOT PLAY
OR A
HARMONIC
IS
MISSING
(Tests to be made
with "Drawbars"
tab
depressed)
This may mean
a
dirty key contact,
a
broken connection,
or a dead note in the
generator.
The steps below will serve
to
isolate
the trouble-
(a)
Ordinarily only
one of the several frequencies used
on the
key will be
missing.
This
can be determined by holding
the key and operating each
drawbar
for that
manual, observing on which drawbar the key falls
to
play
Reference
to the
manual wiring chart, figure
18
will
tell
which frequency
number
is
missing.
(b)
See
whether
the
same frequency
is
missing where
it is
used on other keys
of the same manual. The wiring chart will tell with what other key and
19