Marantz 1060 - Trouble Analysis and Solutions; Troubleshooting Common Issues; Power Amplifier Adjustment

TROUBLE ANALYSIS
Excessive line consumption
No line consumption or zero bias
High hum and noise level
Parasitic oscillation
improper clipping
POWER AMPLIFIER ADJUSTMENT
Check for shorted HOO7, H802, H803.
Check for shorted transistor HOO1 through
HO04.
Check L001 for short.
Check line cord, fuse, shorted HOO5, HOO6G,
H713, H714.
Check for open rectifiers HOO7, H802, H803
or open L001.
Check filter capacitors C003, C703, C704.
Check for defective C713, C714, C727
through C730.
Check for proper adjustment R723 and
R724,
Connect
a
VTVM
across
the
resistor
R747
and
adjust
the
trimming
resistor
R729
until
the
VTVM
reads
7.5mV
DC.
For
the
other
channel
connect
the
VTVM
across
the
R748
and
adjust the R730 for the same reading.
Connect
a
oscilloscope
across
the
speaker
terminals.
Apply
an
audio
signal
of
1
KHz
to
the
AUX
jacks
and
increase
the
audio
signal
until
the
audio
output
on
the
scope
begin
to
clip.
Adjust
the
trimming
resistor
R723
for
equal
and
symmetrical
clipping.
For
the
other
channe!
adjust the R724.