Harman Kardon HD7725 - Page 10

3. Optical Pick-up Laser Power Adjustment
The specified value for adjustment varies with the type of the
pick-up in use. Obtain the voltage value according to the
following procedure.
(a) Read the current value on the label of the pick-up P.C. board.
(b) Using the amperage of the current and the following
equation, calculate the voltage value. When the current is
44.1mA; V=0.0441A x 22=0.9702V.
(1) Connect the DC voltmeter to both ends of R101.
(2) Insert EIAJ CD-1 test disc and place the unit in the Play mode.
(3) Adjust VRO1 in the pick-up P.C. board to the voltage
obtained in step (b) above.
Label
KSS-210A
12Y90
Kaat
t—§—aa1tma
4. EF Salance Adjustment
(1) Connect the oscilloscope (0.5V/div, 5msec./div, DC mode} to
TP101 and GND.
Short-circuit TP401 and GND.
(2) Insert EIAJ CD-1 test disc and place the unit in the Play mode.
{3) Adjust VR101 so that the amplitude above and below the
zero DC line becomes equal (Amplitude A = Amplitude B).
Oscilloscope
“OEE ‘3;
-| 3°
¢ 4 O PROBE(10:1, Impedance; more
° | than 1MQ, Capacitance; less
[SECEEEEEEELD | than 25pF)
042100 6 0 oles lls
(iL TP101
GND
mo
[<—>le—>|
2 >
A=B
{approx. 1.5Vp-p)
5. Focus Offset Adjustment
(1) Connect the Jitter meter to TP201 and GND.
{2) Insert EIAJ CD-1 test disc and place the unit in the Play mode.
(3) Adjust VR102 until the jitter for optimum sensitivity.
Jitter Meter
LEE TP201
— GND
6. Jitter Inclination Confirmation
(1) Connect the Jitter meter (sigma range) to TP201 and GND.
(2) Insert EIAJ CD-1 test disc and place the unit in the Play mode.
(3) Confirm the jitter meter reading is less than 30ns.
Jitter Meter