Adjustment Procedures - Grundig CDM 700 Service Manual

Einstellvorschriften / Adjustment Procedures

Adjustment Procedures

1. CD-Section
Measuring instruments: Oscilloscope
Note: Do not turn the variable resistor for laser power adjustment. The laser current is pre-set at the factory.
Position of testpoints see page 3 - 7 "CD Board".
Adjustment Adjustment Adjustment Preparations Preparations Preparations
Tracking EF Balance Tracking EF Balance Tracking EF Balance Connect the Oscilloscope to testpoint TSO or Pin35 of
IC2, ground to Vref or Pin3 of IC2.
- Load a CD
- Close the CD door
- CD Function: Play - Pause
- The button SKIP UP T is used to select the tracks
successively (control VR2 can be adjusted during the
search process).
Focus Offset Focus Offset Focus Offset Connect the Oscilloscope to testpoint RF or Pin2 of IC2,
ground to Vref or Pin 3 of IC2.
- Load a CD
- Close the CD door
- CD Function: Play
2. Cassette Deck 2. Cassette Deck 2. Cassette Deck
Measuring instruments/equipment: Frequency counter, AF-voltmeter, wow and flutter meter, Measuring instruments/equipment: Frequency counter, AF-voltmeter, wow and flutter meter, Measuring instruments/equipment: Frequency counter, AF-voltmeter, wow and flutter meter,
Fe test cassette 449 (Part No. 35079-019.00), torque test cassette 456 (Part No. 35079-014.00). Fe test cassette 449 (Part No. 35079-019.00), torque test cassette 456 (Part No. 35079-014.00). Fe test cassette 449 (Part No. 35079-019.00), torque test cassette 456 (Part No. 35079-014.00).
Position of testpoints see page 3 - 12 "Tape Board"
Adjustment Adjustment Adjustment Preparations Preparations Preparations
1. Tape speed Connect the frequency counter to the headphone socket.
Insert the test cassette 449, play 3150Hz.
2. Take-up torque on Insert the torque test cassette 456.
Start Function: Playback-Start.
3. Wow and flutter Connect the wow and flutter meter to the headphone
socket. Insert test cassette 449, play 3150Hz.
4. Head gap angle Connect the AF-voltmeter to the headphone socket.
(Azimuth) Insert test cassette 449,
play 8kHz.
5. Bias frequency Connect the frequency counter to TP4 (connector CN405).
Insert a recordable cassette.
Function: Record-Start.
6. Bias voltage Connect the AF-voltmeter via a 1:1000 capacitive voltage
divider to TP4 (connector CN405). Insert a recordable
cassette.
Function: Record-Start
2 - 3
CDM 700
Adjustment Processs Adjustment Processs Adjustment Processs
Adjust VR2 so that the graph is symmetrical to the 0-line Adjust VR2 so that the graph is symmetrical to the 0-line Adjust VR2 so that the graph is symmetrical to the 0-line
(Vref). (Vref). (Vref).
V1
0 (Vref)
V2
V1 = V2
Adjust VR1 to obtain a clear eye pattern as shown in the Adjust VR1 to obtain a clear eye pattern as shown in the Adjust VR1 to obtain a clear eye pattern as shown in the
diagram. diagram. diagram.
max. (1.3V
± 0.3V pp)
Adjustment Process Adjustment Process Adjustment Process
With adjustment control (in the
cass.-motor) set the frequency
±
to 3150Hz 3.15Hz.
MOTOR MOTOR MOTOR
Tape tension on: Playback-Start = 35 - 80g-cm
Fast Forward = 50 - 90g-cm
Fast Rewind = 50 - 90g-cm
Deviation < 0.3% (aurally compensated). Playback
measuring time ≥ 30 seconds.
1
With the head adjustment screw 1 set the
left and right channel to maximum level.
The levels of the two channels mustnot
differ by more than 3dB.
±
The oscillator frequency should be 65kHz 3kHz.
Adjust with T401 (Tape Board).
The bias voltage is approx. 12V (measured with a 1:1000
capacitive voltage divider).
GRUNDIG Service
Einstellvorschriften / Adjustment Procedures
3. Tuner
Measuring instruments: Signal Generator, DC Voltmeter, Oscilloscope.
Adjustment Preparations
1. AM IF Couple in a standard signal of 460kHz to T604 (ferrite
aerial) via a loop aerial. U as low as possible.
a
Oscilloscope to loudspeaker output.
2. MW Oscillator MW f 531kHz, f 1602kHz
u o
DC Voltmeter to testpoint AMVT.
3. MW Aerial MW 603kHz, MW 1404kHz
bandpass Couple in a standard signal to T604 (ferrite aerial) via a
loop aerial, (f = 1kHz, m = 30%).
mod
Oscilloscope to loudspeaker output.
4. FM IF Couple in a standard signal of 98MHz to testpoint TP1.
U as low as possible.
a
Oscilloscope to loudspeaker output.
5. FM Oscillator FM f 108MHz, f 87.5MHz
o u
DC Voltmeter to testpoint FMVT.
6. FM Aerial FM 90MHz, FM 106MHz
bandpass Couple in a standard signal to (FM ant.) testpoint TP1,
= 1kHz, ∆f = 22.5kHz, U
(f as low as possible).
a
mod
Oscilloscope to loudspeaker output.
T604
L601
TC601
T603
L602
T602
TC602
TC603 T605
MAIN BOARD
2 - 4
Adjustment Process
Adjust T603 to maximum.
At f (531kHz) adjust to 1.0 + 0.1V with T605.
u
(1602kHz) adjust to 7.2 ± 0.1V with TC603.
At f
o
Repeat this adjustment.
At 603kHz adjust to maximum with T604 (MW antenna coil
move).
At 1404kHz adjust to maximum with TC602.
Repeat this adjustment.
With T602 adjust to maximum.
(108MHz) adjust to 6.3 ± 0.2V with L602.
At f
o
87.5MHz) 2.2 ± 0.2V.
Check at (f
u
At 90MHz adjust to maximum with L601.
At 106MHz adjust to maximum with TC601.
Repeat this adjustment.
TP1
Ant.
J14
J13
FMVT
AMVT
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CDM 700