Samsung SCM-7270 Service Manual page 16

Alignment and Adjustments
4-3 CD
TE CENTER FE CENTER
E.F BAL
F.BIAS
NVR1704 NVR1703 NVR1702 NVR1701
TP1
TP2
4-3-1 To Adjust FOCUS BIAS (STOP mode)
1. Set Volt/Div of the oscilloscope to DC 100mV.
2. Ground the scope input and set the waveform to 0V, DC range.
3. Connect the GND terminal of the oscilloscope to Vref,
and (+) terminal to center of TP1.
4. Set NVR1701 to 0mV.
4-4
Vref
4-3-2 To Adjust Tracking Gain (PLAY mode)
1. Connect the ground terminal of the oscilloscope to Vref and (+) terminal to TP2.
2. Load and play the disc.
3. While the disc is running, adjust the gain with NVR1704 as shown below.
Low Frequency
Normal Frequency
0V
VOLT/DIV : 0.2V
VOLT/DIV : 0.2V
TIME/DIV : 2mS
TIME/DIV : 2mS
4-3-3 To Adjust Focus Gain (PLAY mode)
1. Connect the ground terminal of the oscilloscope to Vref and (+) terminal to TP1.
2. Load and play the disc.
3. While the disc is running adjust the gain with NVR1703 as shown in the following figure.
Low Frequency
Normal Frequency
100mV
0V
VOLT/DIV : 0.1V
VOLT/DIV : 0.1V
TIME/DIV : 2mS
TIME/DIV : 2mS
4-3-4 To Adjust E/F Balance (PLAY mode)
1. Set Time/Div of the oscilloscope to 2mS.
2. Set Volt/Div of the oscilloscope to 0.5V.
3. Ground the scope input and set to DC, and then
set the DC range.
4. Connect the ground terminal of the oscilloscope to Vref
and (+)terminal to center to TP2.
5. Load and play the disc.
6. Turn NVR1704 counterclockwise to the minimum value.
7. Raise NVR1702 and adjust the waveform so that its middle
comes to ground of the oscilloscope, (or until the upper half
of waveform becomes symmetrical to the bottom half,A=B).
8. Adjust NVR1704(arrow) for normal sound.
High Frequency
0V 0V
VOLT/DIV : 0.2V
TIME/DIV : 2mS
High Frequency
250mV
100mV
0V
0V
VOLT/DIV : 0.1V
TIME/DIV : 2mS
0V
A=B
Samsung Electronics