Dual CR 900 RC Serviceanleitung Seite 3

Tuning lnstructions for CR 900 RC
L
Signal source Equipment
setting
Signal source setting Connection of
measuring instrument
Item to be tuned
Tuning, Remarks
1) FM oscillator
87.5 MHz DC voltmeter
to TP 1 (R 402)
L 4 8.0V DC ± 0.2V
108 MHz Check approx. 1.6V DC
2) FM IF, input circuit
FM signal generator
to 75 ohm
antenna input
Frequency
without
transmitters
approx. 98 MHz
0-1 mV, Shift ±
40 kHz, Mod. 1 kHz
Tune to approx.
98 MHz
Harmonic detector
oscilloscope
to AF output
Ti AF maximum
L 404
L 405 AF and harmonic
minimum
approx. 90 MHz Tune to approx.
90 MHz
I
aircoils
L 1, L2, L3
Maximum
3) FM IF (fine tuning)
Antenna to 75 ohm
antenna input
Receive strong
FM transmitter
at its nominal
frequency
DC voltmeter
to TP 3—TP 4
(over R 412)
L 405 Determine DC max. and DC min.
L 405 Adjust power mean
[404 OVDC± 10 mV
Repeat tuning
4) Pilotfrequencies 76 kHz, Channel separation
FM Signal generator
to 75 ohm
antenna input
Frequency
without
transmitters
approx. 98 MHz
Mono key: OFF
Tune to approx. 98 MHz
Shift ± 40 kHz,
Mod. 1 kHz
1-2 mV, without pilot
Frequency counter
to TP 5
(bridge 3 J 47)
VR 501 76 kHz ± 50 Hz
with 19 kHz pilot AF voltmeter,
oscilloscope
to AF output
VR 502 Maximum channel separation
5) Suppression of residual pilot frequencies (19 kHz)
FM Signal generator
to 75 ohm
antenna input
Frequency
without
transmitters
approx. 98 MHz
Tune to approx.
98 MHz, 1-2 mV
19 kHz pilot ON
AF voltmeter,
oscilloscope
to AF output
[PF (lett channel) Minimum
[PF (right channel)
6) FM Search threshold
FM Signal generator
to 75 ohm
antenna input
Frequency with-
out transmitters
approx. 98 MHz
Tune to approx. 98 MHz
Shift ± 40 kHz,
Mod. 1 kHz, 10 µV
Check the display VR 401 Signal.
la
must light up
7) AM oscillator
AM 522 kHz
DC voltmeter
to TP 1 (R 402)
[402 1.6V DC ± 0.1 V
AM 1611 kHz TC 402 8.4 V DC ± 0.4V
Repeat tuning
8) AM IF, Input circuit
AM Signal generator
to AM antenna
input 999 kHz
10 µV-1mV, 1 kHz
Mod. 30%
999 kHz
AF voltmeter,
oscilloscope
to AF output [403
Maximum
603 kHz 603 kHz
L401
1404 kHz 1404 kHz
TC 401
9) AM Search threshold
AM Signal generator
to AM antenna
input
999 kHz
100 µV, 1 kHz
Mod. 30%
999 kHz
Check the display
VR 402
Signal 13
in
must light up
3