Grundig RRCD 2420 MP3, Service Documents

Page: 2 / 15

RRCD 2420 MP3
ǵ
INSTRUMENTS REQUIRED GENERAL PREPARATION
1. Signal Generator 1. Check source voltage, DC or AC according to specificaions
2. FM Signal Generator 2. Set function switch to band being aligned
3. FM/AM IF Sweep Generator (10.7 MHz for FM) 3. Signal input should be kept as low as possible to avoid AGC and AFC function
4. VTVM 4. Standard modulation :
AM 1 KHz 30% mod
5. Oscilloscope
FM 1 KHz 22.5 KHz dev
6. Frequency counter
7. Regulated DC power supply
AM IF ALIGNMENT
STEP
SIGNAL SOURCE (AM RF Gen.)
CONNECT TO
SET SIGNAL
TO
ALIGNMENT INDICATOR (Oscilloscope, VTVM)
CONNECT TO
SET RADIO
DIAL TO
ADJUST ADJUST FOR REMARKS
TP3
A standard radiation 450KHz Detector output terminal Quiet Volume control at
1 loop and ground (TP4) Point T601 Maximum min. position
2 Repeat step 1 for max. output
FM IF ALIGNMENT
This model requires no FM IF alignment as the IF is fixed by ceramic filter and discriminator CF502 or CF503 & CF505. Please take note that correct type and same color dot of ceramic filter is used
in servicing, diff color dot of ceramic filter may cause worse IF 'S' curve characteristic and distortion.
Connect IF genescope output terminal to TP3 & TP4 (GND) in series with a 1000Pf capacitor, connect scope input terminal to TP1 & TP2 (GND), then the IF characteristic curve can be observed.
A L I G N M E N T P R O C E D U R E
STEP
SIGNAL SOURCE (FM Signal Gen.)
CONNECT TO
SET SIGNAL
TO
ALIGNMENT INDICATOR (Oscilloscope, VTVM)
CONNECT TO
SET RADIO
DIAL TO
ADJUST ADJUST FOR REMARKS
87.5 MHz 87.5 MHz NA
NA
Digital DC
1
(modulated) (Lowest end) Volt meter is
L604 (Osc. Coil)
Connected to
TP1 & TP2 108 MHz Terminals 108 MHz
stretch or DC 8V
±
0.3V
TP 5 and grg
2 through matching network (modulated) across speaker (Highest end) squeeze
if necessary voice coil L601 (RF coil)
3
88 MHz
88 MHz stretch or Volume
(modulated) squeeze Maximum control at
106 MHz TC 601
max. position
4 (modulated) 106 MHz (RF trimmer)
5
Repeat steps 3 and 4 as necessary to minimize tracking error and also steps 1 and 2 if necessary
AM RF ALIGNMENT
STEP
SIGNAL SOURCE (AM Signal Gen.)
CONNECT TO
SET SIGNAL
TO
ALIGNMENT INDICATOR (Oscilloscope, VTVM)
CONNECT TO
SET RADIO
DIAL TO
ADJUST ADJUST FOR REMARKS
522 KHz 522 KHz Digital DC
1
(modulated) (Lowest end) NA
NA
Volt meter is
1620 KHz 1620 KHz L 605
Connected to
2
A standard radiation (modulated) Across speaker (Highest end) (Osc.Coil) DC 8V
±
0.3V
TP 5 and grg
loop ant. 603 KHz voice coil L 603 Volume
3 (modulated) 603 KHz (ant. coil) Maximum control at
1404 KHz TC 603
max. position
4
(modulated) 1404 KHz (ant. trimmer)
5
Repeat steps 3 and 4 as necessary to minimize tracking error and also steps 1 and 2 if necessary
Applicable unit :
1 This model is using CD drive unit No. SANYO DA11B3V
2 The alignment for CD section is fully automatic and no adjustment is reguired
FM RF ALIGNMENT
ALIGNMENT PROCEDURE FOR CD SECTION
1 ) Check source voltage, DC or AC according to specifications . 2 ) Set function switch to Tape being aligned .
A ) MEASURING INSTRUMENTS REQUIRED FOR TAPE B ) EQUIPMENTS REQUESTED FOR AC BIAS FREQUENCY / CURRENT ADJUSTMENT :
SPEED AND HEAD AZIMUTH ADJUSTMENT.
( 1 ) TAPE SPEED ADJUST
MTT-111 (3000 Hz) TEST
°
AC BIAS FREQUENCY ALIGNMENT :
Note :The test unit should be keep in recording mode and added two resistors Ra & Rb as shown in the
Fig. 2 before alignment. be sure to delete the both resistors Ra & Rb after alignment completed.
( 2 ) HEAD AZIMUTH ADJUSTMENT . Test Point Adjust Frequency Frequency Observe at Observe
2.1 - Connect the equipments as shown in the Fig. 1. at Beat 0 Beat 1 Beat 2 Beat 0 Beat 1 Beat 2
(The Both Speakers loading Are Required) Resistor
2.2 - Insert a test tape ( 10 KHz : MTT-114 ) into deck.
Ra or Rb L401 60KHz
±
0.3KHz 54KHz
±
2KHz
2.3 - Press PLAY and set VOLUME at reference output.
2.4 - Adjust the azimuth adjustment screw for the max.
& balance ch. output on both ch. of oscilloscope.
2.5 - Secure above screw with glue after adj. completed.
GENERAL PREPARATION -
==> TO CASS PCB
CN401
60KHz
1
Ra
10 ohm
Rb
10 ohm
4
INPUT
OUTPUT
VTVM
FREQUENCY
COUNTER
FIG.2
R/P HEAD
MOTOR
SPEAKER
TERMINALS
AZIMUTH ADJ. SCREW
TAPE IS REQUIRED
R/P HEAD
OSCILLOSCOPE
CH. 2
3000 Hz
CH. 1
FREQUENCY
COUNTER
FIG.1