Aiwa NSX-AJ305 U Service Manual page 55

ELECTRICAL MESUREMENT
• Perform the adjustments after the machine enters the test mode.
• Place the CD mechanism horizontally level.
• Equipment and tools required
Measuring equipment: Oscilloscope (Use the probe of 10:1)
Test disc:
1. RF Waveform Check
1) Connect an oscilloscope to test point (IC101 4pin, RF), (IC101 11pin, Vref).
2) Play back the 2nd track of the TCD-782.
3) Check to see that the RF waveform has the maximum amplitude
and the center of the wedge waveform has the clear blank.
2. Jitter Check
1) While an oscilloscope is kept connected in the same test point
as in the 2. RF Waveform Check, connect the output terminal
of an oscilloscope to the input terminal of a jitter meter.
2) Set the VOLT range selector of an oscilloscope to 500 mV
range or lower.
3) Play back the 2nd track of the TCD-782.
4) Check to see that a jitter meter indicates 40.0 ns or less.
3. Tracking Balance Check
1) Connect an oscilloscope to test point (TE), (VREF).
2) Play back the 2nd track of the TCD-782 and press the PAUSE
button.
3) Check to see that the traverse waveform on an oscilloscope is
vertically symmetrical.
45. Play-ability Check
1) Play back the 4th, 9th and 13th track of ATD-001. Check to see
that noise does not occur and sound skipping does not occur.
6. Laser Current Check
*Do not perform this measurement unless the laser is suspected to be
defective.
1) Connect a Digital Multimeter across the resistor R8 (3.3 ohms).
2) Play back the TCD-782 and check the DC voltage value on a Digital
Multimeter.
3) Calculate the laser current (Iop) by dividing the DC voltage across
R8 by the resistor value.
Laser current (Iop) = DC voltage across R8 divided by the
resistor value (3.3 ohms).
5ZL-3 R3 : Check to see that the laser current (Iop) is 80 mA or less.
KSS-213F : Check to see that the laser current (Iop) is SPEC VALUE +15%.
(Refer to the EXAMPLE)
Digital Multimeter (Use it in the DC Volt range.)
Jitter meter (Kikusui 6235 or equivalent)
TCD-782
ATD-001
OSCILLOSCOPE
+
--
RF
VREF
OSCILLOSCOPE
+
--
RF
VREF
OSCILLOSCOPE
+ --
TE
VREF
-16-
EYE PATTERN
must be CLEAR and MAX.
OUTPUT
VOLT/DIV: 500mV
TIME/DIV: 0.5µS
AC INPUT
JITTER METER
OUTPUT INPUT
VREF
OUTPUT
VOLT/DIV: 500mV
TIME/DIV: 1mS
DC INPUT
DIGITAL MULTIMETER
V
+ --
R8
R8
R EXAMPLE
KSS -213F
05Y93
DA372
SPEC VALUE
37.2mA
1.8 Vp-p
0V
ns
A
B
A=B