RR 640 CD / RR 670 CD
Abgleichvorschriften / Adjustment Procedures
GRUNDIG Service
2 - 4
2. Tuner
Measuring instruments:
Signal generator, sweep generator, oscilloscope, frequency counter.
Function switch: Radio
Adjustment
Preparations
Adjustment Process
Adjust to
maximum
with
T501.
At f
u
(515kHz) adjust to
maximum
with
L504
.
At f
o
(1630kHz) adjust to
maximum
with
VCT501(B)
.
Repeat this adjustment alternately.
At 558kHz
adjust to
maximum
with
L506
(MW aerial coil,
move).
At 1440kHz
adjust to
maximum
with
VCT501(A)
.
Repeat this adjustment alternately.
At f
o
(292kHz) adjust to
maximum
with
TC502
.
At 153kHz
adjust to
maximum
with
L507
(LW aerial coil,
move).
At 261kHz
adjust to
maximum
with
TC501
.
Repeat this adjustment alternately.
At f
u
(87.35MHz) adjust to
maximum
with
L503
.
At f
o
(108.25MHz) adjust to
maximum
with
VCT501(C)
.
Repeat this adjustment alternately.
At 88MHz
adjust to
maximum
with
L502
(bend).
At 106MHz adjust to
maximum
with
VCT501(D)
.
Repeat this adjustment alternately.
Set the frequency to
76kHz
±
100Hz
with
VR501
.
Couple in a
sweep signal
of 465kHz to
L506
(ferrite aerial)
via a loop aerial.
Oscilloscope
to testpoint
TP 6
/
TP 7
(CN501 Pin 1/3).
Band switch: MW
Var. capacitor to limit stop: MW f
u
515kHz, f
o
1630kHz
Couple in a
standard signal
to
L506
(ferrite aerial)
via a
loop aerial, (f
mod
= 1kHz, m = 30%, U
a
as low as possible so
that the signal is just visible).
Oscilloscope
to testpoint
TP 6
/
TP 7
(CN501 Pin 1/3).
Band switch: MW
MW 558kHz, MW 1440kHz
Couple in a
standard signal
to
L506
(ferrite aerial) via a
loop aerial, (f
mod
= 1kHz, m = 30%, U
a
as low as possible so
that the signal is just visible).
Oscilloscope
to testpoint
TP 6
/
TP 7
(CN501 Pin 1/3).
Band switch: MW
Var. capacitor to limit stop: f
o
292kHz
Couple in a
standard signal
to
L507
(ferrite aerial) via a
loop aerial, (f
mod
= 1kHz, m = 30%, U
a
as low as possible so
that the signal is just visible).
Oscilloscope
to testpoint
TP 6
/
TP 7
(CN501 Pin 1/3).
Band switch: LW
LW 153kHz, LW 261kHz
Couple in a
standard signal
to
L507
(ferrite aerial) via a
loop aerial, (f
mod
= 1kHz, m = 30%, U
a
as low as possible so
that the signal is just visible).
Oscilloscope
to testpoint
TP 6
/
TP 7
(CN501 Pin 1/3).
Band switch: LW
Var. capacitor to limit stop: FM f
u
87.35MHz, f
o
108.25MHz
Couple in a
standard signal
via a 10nF capacitor
to
testpoint
TP 1
/
TP 2
(GND) (f
mod
= 1kHz,
∆
f = 22.5kHz, U
a
as low as possible so that the signal is just visible).
Oscilloscope
to testpoint
TP 6
/
TP 7
(CN501 Pin 1/3).
Band switch: FM
FM 88MHz, FM 106MHz
Couple in a
standard signal
via a 10nF capacitor
to
testpoint
TP 1
/
TP 2
(GND) (f
mod
= 1kHz,
∆
f = 22.5kHz, U
a
as low as possible so that the signal is just visible).
Oscilloscope
to testpoint
TP 6
/
TP 7
(CN501 Pin 1/3).
Band switch: FM
Standard signal
none
Short-circuit IC501 between Pin 1 and Pin 29.
Frequency counter
to test point
TP 5
(IC501 Pin 4).
Band switch: FM
1. AM IF
2. MW Oscillator
3. MW Aerial
bandpass
4. LW Oscillator
5. LW Aerial
bandpass
6. FM Oscillator
7. FM Aerial
bandpass
8. FM MPX (Stereo)
TP 2
TP 1
TP 7
TP 6
TP 5
