Service manual
Checkou
Procedures
5,16
ODEP
Limiting
5.17
Mute
and
Turn
On
Delal
Spss:
No
ascillatisn
on
ODEP
Limiting
wave
form\
Sp@@:
Clamps
signal;
3
ts
5
second
turn
on
delay,
QDEP
LED
dims
and
Is
out
as
the
amplifier
starts
QDEP
initisi
Coadition%:
Controls
per
staradard,
fimiting.
Either
channel
esntrols
limiting
in
Paratief
Moue
PP@@@$u~@:
NO
load.
inject
a
1
kHz
sine
wave
into
both
Mode.
channels.
Observe
the
output
signal
with
an
assillpa-
initsat
Con@itlong:
Centrals
per
standard;
rag
or
other
scope.
Turn
the
amplifier
off
with
the
front
panel
switch.
obstruction
blocking
fan
so
that
it
does
not
turn.
The
amplifier
should
clamp
the
signal,
not
allow
it
to
Ftacedufe::
Load
the
amplifier
to
4
ohms
ou
each
chan-
decay
with
the
pswer
supplies.
Turn
the
amplifier
back
net,
Inject
a
sine
wave
with
the
same
frequency
as
the
an
and
observe
the
3
to
5
second
deiay
before
it
comes
AC
power
line.
REF
i
output
level
.--
40
VAC.
REF
I!
back
out
of
standby"
Note
thal
both
channels
may
not
&a~fpkifleve1
=
28
VA6,
After
a
few
minutes
observe
a
come
out
of
standby
at
the
exact
same
time.
wave
form
similar
to
Figure
5'9.
Remove
the
input
sig-
nal
from
both
channels
and
ailgaw
the
amplifier
to
cogs!
5.1
8
Low
Frequency
Proteclion
for
a
few
minutes.
Switch
the
amplifier
ta
Paraltsi
Mono
$@I@:
Ampiifier
gwutas
for
low
frequency,
and
remove
the
load
from
channel
1.
inject
the
si~nal
InibIail
C~nditions:
C~ntrols
per
standard,
Ento
channel
1
and
obsarve
that
QDEP
limiting
occurs
Frocgdure:
No
/sad.
Inject
a
0.5
HZ
12
voft
peak-to-
at
the
output
BE
both
channels.
Remove
the
load
from
peak
square
wave,
a
2
Hz
"I
ppgak-to-peak
sine
channel
2,
and
instail
the
load
an
channef
3.
Again,
wave
into
each
channel,
one
channel
ak: a
time,
and
observe
that
bath
channels
lirnik
Return
all
amplifier
ygpify
tnat
$he
channel
driven
cycles
into
standby*
once
controls
$0
standard
initiaf conditions.
Remove
the
fan
in
standbys
it
will
lay
to cycle
out
of
standby
every
3
to
obstruction.
5
seconds.
Electrical
Cheekoast
5-4