Onkyo TX-SV525

It should be clear that the base of Q520 should not be more than -1 2vdc and Q518 +1 3vdc Q516 is
It
should
be
clear
that
the
base
of
Q520
should
not
be
more
than
-1
.
2vdc
and
Q518
+1
.
3vdc
.
Q516
is
the bias and its turn on is the potential difference of RC components R540 and R538. Q518 also gets its
t ll d DC i Q526 A i th t th lt lifi i ki tl th th t f
con
t
ro
ll
e
d
DC
v
i
a
Q526
.
A
ssum
i
ng
th
a
t
th
e vo
lt
age amp
lifi
er
i
s wor
ki
ng correc
tl
y,
th
en
th
e amoun
t
o
f
volta
g
e delivered at the base of Q520 and Q518 should be within the tolerance to be
g
overned
g g
(controlled) by Q516.
In general practice two possibilities exist in this case
In
general
practice
two
possibilities
exist
in
this
case
.
1. The base drive voltage coming from Voltage amplifier stage arriving at Q518 and Q520 is to high to
be controlled by Q516 and its associated components.
2. Q516 and its associated switching
+
RC and Voltage divider R
-
Nets are failing. Q526, C538, D506,
2.
Q516
and
its
associated
switching
RC
and
Voltage
divider
R Nets
are
failing.
Q526,
C538,
D506,
D504, R562, are all part of the Q516 operators service as reference control to the bias.
Is the problem 1 or 2 or both?
Is
the
problem
1
or
2
or
both?