Service manual
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Studio
Reference
Service
, , ,,
Manual
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mcrmwn*
Checkou
Procedures
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31.1
-9.69
9-69
5,2
Standard
initial
Cowdltigns
32.2
-9.63
9.63
Level
controls
fully
clockwise.
StereoBMano
switch
in
Stereo.
Sensitivity
switch
in
26
dB
fixed
gain
pasition.
It
is
assumed,
in
each
step,
that
Ehe
conditions
of
the
amplifier
are
per
these
initial
conditions
unless
other-
wise
specified,
-ODEP
Proe8Bure:
Measure
pin
3
of
3500
and,
if
news-
sary,
adjust
R121
to
obtain
V
,,,,
as
specified
above.
Measure
pin
3
of
J700
and,
if
necagsarx
adjust
R22t
to
obtain
V
,,,,
as
s~ecifred
above,
5,3
QC
Offset
+OOEP
~rocgiite:
~easure
pin
4
of
3500
and,
if
neces-
sary,
adjust
R132
to
obtain
V+,,,,
as
specified
above.
Spgc;
8 WBC,
k2
rnV
Measure
pin
4 of
J700
and,
if
necessary,
adjust
R232
lnltial
Ce~dttOax~gr
Controls
per
standard,
mputs
shorted
oblasn
v+OL)EP
as
Preeadurs:
Msasure
DC
voltage
at
the
sutput
canncc-
tors
(rear
panel).
There
is
ns
adjustment
for
output
off-
set.
If
spec
is
not
met,
there
is
an
afectricai
rnaifunc-
tian,
Sligh8fy
out
of
spec
measurEment
is
usually
due
to
U"iQiU204
0165:
of
tolerance,
5.4
Output
Bias
Adjustment
Spec:
300
ta
320
rnVDC,
ilnitiall
Gandstiaa$::
Contrais
per
standard,
healsink
tern-
peratare
less
than
40°C
P~oeedurs:
Measwe
DC
voltages
or?
the
output
mod-
ule
across R02,
adjust
R26
if
B-eecessary,
Measure
DC
voltages
on
the
output
module
across
R21,
adjerst
R23
if
necessary.
Repeat
for
second
channel.
5,6
BC
Power
Draw
Spbc::
70
Wazrs
nmaximkam
quiescent.
initial
Csnditions:
Controls
per
standard.
Procedure:
With
no
input
si~nal
and
BBQ
16ad,
measure
AC
line
wattage
draw.
if
current
draw
is
excessive,
check.
far
high
AC
Iim
voltage
or
high
bias
vsitaga.
5.7
High
Line
Gutout
Spec:
Unit
goes
into
standby
when
the
AC
line
voftage
goes
^f
8%
to
to
12%
aabw
onominal,
lnltial
Gondltionsl:
Controls
par
standard.
Proeedgre:
No
load,
no
signal,
Bring
up
AC
line
volt-
age
with
a
variac
10%
to
12%
high.
Far
120VAC
units
5.5
ODEP
Voltage
Adjustment
this
is
132VAC
is
334.4VAC.
Unit
should
go
into
Spat:
Bias
Per
Chart,
~6,4V
DC.
standby.
Adjust
R4
sn
the
control
module
if
neees-
sary.
InltiaiP
@oiaridition%:
ContnaSs
per
standard,
heatsink
at
room
temperature
20
to
30°C
(68
to
86°F)"
Note:
This
adjustrnerr"rh8ufd
nsrmaliy
be
performed
wilhin
2
r~rintsts%
07
turn
an
from
ambient
(esfd)
cornditions,
If
possible,
measure
healsink
temperature;
if
not,
msa-
sure
ambient
room
temperature.
Use
this
infarmation
when referencing
the
$.a/lawing
chart,
5.8
Common
Mode
Reje~tion
Spac:
>70
dB
at
1
kHz,
initial
Cendilions:
Controls
per
standard,
Prosgdure:
No
load,
Inject
a
0
dBil(.775VRMS),
1
kHz
sine
wav@
into
each
channel,
one
channel
at
a
time,
wieh
inverting
and
non-inverting
inputs
shorted
to-
getkaer.
Adjust
R512
(Chl)
and
RE12
(Ch2)
for
less
than
4,9mVRMS
(-44
dBu)
at
the
amplifier
output.
Elcctrfcal
Checkout
5-1