Marantz ST400 - Muting Circuit Alignment; Multiplex Alignment Procedures (Selector Switch in the FM Position); AM Alignment Procedures (Selector Switch in the AM Position)

Signal Source Signal Indicator Set Dial
Connection Frequency Connection Pointer to:
87.3 MHz 87.3 MHz with L103 for maximum
tuning gang closed. output.
109 MHz with C119 for maximum
VTVMtoLorR tuning gang open. output.
channel output L101, L102 for
_ (wo02) | nO Ms
maximum output.
ANT. RF. TRIM. CAP.
106 MHz :
| for maximum output.
Repeat steps 1 to 4.
Adjust:
RF generator to
FM antenna
terminals ® through
matching network ~
{300 ohms, balanced}
(Maintain RF level
below limit.)
Check overall! response curve and repeat above steps as necessary to obtain maximum sensitivity.
L201 Primary core
(bottom) center tuning
meter pointer indicates
its center,
No connection No signal
L201 Secondary core
(upper) for minimum
distortion.
Distortion meter to
RF generator 1 mV
output to FM antenna
terminals @® through
matching network R232 So that signal
(300
ohms,
balanced)
98
MHz
Strength
meter
MOO1
may read 85%
4.2 Muting Circuit Alignment
Signal Source Signal Indicator Set Dial
Step : é .
Connection Frequency Connection Pointer to:
RF generator 12.5uV R233 for 12.5uV
output to FM antenna VTVMtoRorL threshold tevel. (During
terminals @) through channel output this adjustment turn the
matching network (W 002) muting pushswitch
(300 ohms, balanced) “ON".)
4.3 Multiplex Alignment Procedures (Selector switch in the “FM” position)
Signal Source Signal Indicator Set Dial ‘
: J Adjust:
Connection Frequency Connection Pointer to:
R326 so that Frequency
counter may precisely
read 19 kHz
Frequency counter
RF generator to FM
to point (J140)
antenna terminals
through matching
2 network (300 ohms,
balanced), with ImV
FM stereo simulator
RF fevel and 100%
modulation (pilot 9%)
No Modulation
VTVM to right
channel output
{W002, white)
VTVM to left
channel output
(W002, red)
Repeat steps 2 and 3.
Stereo, left
(1,000 Hz)
R316 for maximum
output and same separa-
tion in both channels.
Stereo, right
{1,000 Hz)
4.4 AM Alignment Procedures (Selector switch in the “AM” position)
1. AM IF Alignment
Signal Source Signal Indicator Set Dial
Connection Frequency Connection Pointer to:
No connection
R228 so that signal
strength meter MOO1
may read 0%
L154 for maximum
and symmetric
response,
No signal
450 kHz
marker
Oscilloscope to
Quiet point on
point © (5141)
Sweep generator to
®
band
point