Kenwood DPC-781 Service Manual page 4

DPC-781/782/981
No. ITEM
SETTING
LASER
1
POWER
FOCUS Test disc
2
ERROR KTD-03
TRACKING Test disc
3
ERROR KTD-03
Test disc
KTD-03 Apply
signal of
1.0kHz,
FOCUS
4
0.05Vrms
GAIN
between
Check-land F1
and F2.
Test disc
KTD-03 Apply
signal of
TRACKING 1.0kHz,
5
GAIN 0.05Vrms
between
Check-land T1
and T2.
Note: Test DISC KTD-03, TCD-783 or equivalent
LPF : Around 47kΩ + 390 pF or so.
Step 1~5 are in Test Mode.
(d) Focus Gain
Two VTVMs should read the same
value.
1.0kHz
0.05Vrms
4
ADJUSTMENT
INPUT OUTPUT
SETTING
Apply the sensor
section of optical
– power meter on
the
pickup lens.
Connect an oscillo-
scope as follows.
CH1:RF
(Check-land RF)
CH2:T1
(Check-land TE1)
Connect an oscillo-
scope as follows.
CH1:RF
(Check-land RF)
CH2:T1
(Check-land TE1)
Connect a LPF
between Check-
land F1 and F2 to
which connect an
oscilloscope or AC
voltmeters.
Connect a LPF
between Check-
land T1 and T2 to
which connect an
oscilloscope or AC
voltmeters.
AC voltmeter
F1
L.P.F
F2
VC
L.P.F
PLAYER
SETTING
Short the test land. Confirm
that the display is
" ".
Press FF Key and confirm
that the display is 03.
Press the PLAY key .
Confirm that the display is
"05".
Press the FF key.
Confirm that the display is
" ".
Press the PLAY key .
Confirm that the display is
"05".
Press the PLAY key .
Confirm that the display is
"05".
(e) Tracking Gain
Two VTVMs should read the same
value.
1.0kHz
0.05Vrms
ALIGNMENT
ALIGN FOR
POINT
On the power from
0.08 to 0.15 mW,
when the diffraction
– grating is correctly
aligned with the RF
level of 1.0 Vp-p or
more.
FE
BALANCE Optimum eye pattern
VR3
TE
Symmetry between
BALANCE
upper and lower
VR5
Two VTVMs should
FOCUS
read the same
GAIN
value.
VR4
TRACKING
Two VTVMs should
GAIN
read the same
VR6
value.
AC voltmeter
T1
L.P.F
T2
VC
L.P.F
FIG.
–
–
–
(d)
(e)