Philips FR980 - ALIGNMENT PROCEDURES; Main Amp Idling Current Adjustment; AM IF Adjustment

2-2
5. Volume reset
This
service
program
can
be
reset
"MASTER
VOLUME
LEVEL"
and
"CHANNEL
OUTPUT
LEVEL"
to
initial
level.
(MASTER
VOLUME
:
-64dB,
CHANNEL
LEVEL
:
0dB)
When
the
POWER
ON,
transmit
the
reset
code
"163731"
continually
more
than
3
seconds
by
remote
control
unit
.
FLD shows
"VOL RST".
TEST EQUIPMENT REQUIRED
1) AM/FM Signal Generator
2) Video Signal Generator
3) Digital Multimeter
4) Distortion level meter
ALIGNMENT PROCEDURES
1. Main amp idling current adjustment
1)
With
the
power
OFF,
set
semi
-
fixed
resistor
R743
(Lch),
R744
(Reh),
R786
(Center
ch)
on
the
PC
board
(P704)
to
the
center
position.
2)
Connect
a
digital
voltmeter,
set
for
the
DC
range,
on
the
emitter
resistor
[R759
(Lch),
R760
(Reh),
R794
(Center
ch)]
on
the
PC
board
(P704).
3) After the above,adjust the idling current as follows:
Turn
the
power
ON
and
adjust
semi-fixed
resistor
R743
(Lch),
R744
(Rch),
R786
(Center
ch)
while
observing
the digital multimeter indication.
The target value is 7.2 mV (20 mA).
All
values
are
with
no
load
on
speaker
terminals,
volume
set
to
minimum
and
no
input
with
the
unit
switchedto
the
CD
position.
Always
allow
the
amplifier
to
stabilize
for
10
minutes
or
longer
prior
to
adjusting
idle
current.
2. Main amp DC offset adjustment
1)
With
the
power
OFF,
connect
a
digital
voltmeter,
set
for
the
DC
range,
to
the
speaker
terminal.
2) After the
above,
adjust
the
DC offset
as
follows:
Turn
the
power
ON and
adjust
RN63
(Lch),
RN64
(Rch),
RN70 (Center
ch)
so
that
the
output is +20
mV.
3. AM IF Adjustment
Input Signal Source Signal Source Signal Output Reception | Adjustment | Adjustment
Connection
Frequency
Level
and
Modulation
Frequency
Point
Value
Output levet
Tuni ‘ (L or R)
uning point LAOQ6 Maximum
at TAPE-OUT
This
adjustment
is
normally
not
necessary,
because
the
coil
LAO6
is
preset
by
the
original
supplier.
Signal Source Signal Output Reception | Adjustment| Adjustment
Frequency Level and Modulation Frequency Point Value
Output level
Level 300 - 400 pV/m (Lor R)
603 kHz Mod. 400 Hz 30% Gos nie lac Maximum
it TAPE-OUT
OD utput level
1404 kHz CA01
Signal generator output to
transmission “loop antenna.
(*:Standard required loop)
Level 300 pV/m (50dB/m)
Mod. 400 Hz 30%
999 kHz
4. AM Tracking Adjustment
**Input Signal Source
Connection
Signal generator output to
transmission *loop antenna.
(*:Standard required loop)
Level 300 - 400 pV/m (L or R)
1404 kHz Mod. 400 Hz 30% Maximum
t TAPE-OUT
Repeat step 1 and 2 until sensitivity be maximized.
PCS 98 390