Grundig K-RCD 120 Serviceanleitung Seite 12

Einstellvorschriften / Adjustment Procedures
3. Tuner
Measuring instruments: Signal Generator, Sweep Generator, Oscilloscope, Frequncy Counter.
Function switch: Radio
Adjustment
1. AM IF Couple in a standard signal of 455kHz to L105 (ferrite
aerial) via a loop aerial.
Oscilloscope to headphone socket.
Band switch: AM
2. MW Oscillator Var. capacitor to limit stop: MW f
Couple in a standard signal to L105 (ferrite aerial) via a
loop aerial, (f
signal is just visible).
Oscilloscope to headphone socket.
Band switch: AM
3. MW Aerial MW 600kHz, MW 1400kHz
bandpass Couple in a standard signal to L105 (ferrite aerial) via a
loop aerial, (f
signal is just visible).
Oscilloscope to headphone socket.
Band switch: AM
4. FM IF Couple in a sweep signal of 98MHz via 5pF to TP1 (FM-
Ant.). Oscilloscope to TP3 (IC102 Pin9).
Band switch: FM
5. FM Oscillator Var. capacitor to limit stop: FM f
Couple in a standard signal via a 5pF capacitor to (FM
ant.) TP1, (f
signal is just visible).
Oscilloscope to headphone socket.
Band switch: FM
6. FM Aerial FM 90MHz, FM 106MHz
bandpass Couple in a standard signal via a 5pF capacitor to (FM
ant.) TP1, (f
signal is just visible).
Oscilloscope to headphone socket.
Band switch: FM
9. FM MPX (Stereo) Couple in a standard signal of 98MHz, unmodulated via
a 5pF capacitor to TP1 (FM ant.).
Frequency counter to testpoint TP4.
Band switch: FM
2 - 4
Preparations
526.5kHz, f
u
= 1kHz, m = 30%, adjust U so that the
mod
= 1kHz, m = 30%, adjust U so that the
mod
87.5MHz, f
u
= 1kHz, ∆f = 22.5kHz, adjust U so that the
mod
= 1kHz, ∆f = 22.5kHz, adjust U so that the
mod
TUNER BOARD
SW101
FM
ANT.
TP1
L102
VC1
IFT101
L103
TP3
R106
VR01
TP4
Adjust IFT102 to maximum.
1606.5kHz At f (526.5kHz) adjust to maximum with L104.
o u
At f (1606.5kHz) adjust to maximum with VC3.
o
Repeat this adjustment.
At 600kHz adjust to maximum with L105 (MW antenna coil
move).
At 1400kHz adjust to maximum with VC4.
Repeat this adjustment.
With IFT101 and IFT103 adjust to maximum and
symmetry.
108MHz At f (87.5MHz) adjust to maximum with L103.
o u
At f (108MHz) adjust to maximum with VC1.
o
Repeat this adjustment.
At 90MHz adjust to maximum with L102 (bend).
At 106MHz adjust to maximum with VC2.
Repeat this adjustment.
Set the frequency to 76kHz ± 100Hz with VR01.
L105
L104
VC2
VC3
VC4
IFT102
IFT103
K-RCD 120
Adjustment Process
GRUNDIG Service