Denon DCD-2560 Service Manual page 17

Caution for Handling the Laser Pick-up
The laser pick-up KSS-151A is assembled and precisely
adjusted using a sophisticated manufacturing process in our
plant. Do not disassemble or attempt to readjust it. Please keep
the following instructions carefully in handling pick-up.
1. General Care
(1) Storage
Do not store the pick-up in dusty, high-temperatured or
high-humidity environments.
(2) Please take care for preventing from shock by falling down
or careless handling.
2. Laser Diode (LD)
(1) Protect your eyes
The laser beam may damage the human eye, since the
intensity of the focused spot may reach 1.3 x 10* W/cm? even
if the intensity at the objective lens is 400 »W maximum. As
the light beam spreads after focused through the objective
lens, it does not effect you in the place as far as more than
30 cms. However, do not look at the laser light beam either
through the objective lens directly nor another lens or a
mirror.
Poison of As
Since the LD chip contains As (Arsenic), as GaAs + GaAlAs,
as known as the poison, although the poison is relatively
weak, in comparing with others, e.g.As2O3, AsCls etc., and
the amount is small, avoid putting the chip in acid or an alkali
solution, heating it over 200°C or putting it into your mouth.
(3) Avoid surge current or electrostatic discharge
The LD may be damaged or deteriorated by its own strong
light if a large current is supplied to it, even if only a short
pulse.
Make sure that there is no surge current in the LD driving
circuit by switches or else. Be careful to handle pick-up as it
may be damaged in a moment by human electrostatic
discharge. The pins of the LD are short-circuited by solder
for protection during shipment [Soiderded short circuit portion
(A)].
For safety handling of an LD, grounding the human body,
measuring equipments and jig is strongly recommended.
And still it is further desirable to make use of mat on the
platform and floor for handling the LD.
To open the short circuit, remove the soldering quickly with
a soldering iron whose metal part is grounded.
The temperature of the soldering iron should be less than
320°C (30W).
3. X-axis Actuator
(1) The performance of the actuator may be effected if magnetic
material is located nearby, since the actuator has a strong
magnetic circuit. Do not permit dust to enter through the
clearance of the cover.
—_ ie) —
(2) Cleaning the lens
It may change the specifications when dust or dirt is stuck on
the object lens. For cleaning, use a dry lens cleaning paper
applying no excessive pressure to the lens. If it is difficult to
remove it, moisten the paper with a little amount of water. At
this time never drip water other than the lens portion.
4. The Metal Bearing
The metal bearing of Cu-compound sintered alloy is impregnated
with oil. However, supply oil with the specified oil FROIL 947P
(529 0054 007), at the pick-up replacing time. You do not normally
need lublicate the bushing in initializing time nor supplying oil in
running time.
5. Handling
Please handle the laser pick-up with holding by optical base.
When either a part of human body or some other things may
happen to touch directly with the circuit part of either the LD or
PD PCB, it may cause deterioration, take careful attention in
handling this base.
6. Deterioration of Laser Pick-up
When difficulty occurs either in focus or tracking adjustment nor
able to adjust the focus or tracking, it seems that the laser pick-up
is deteriorated. In these cases, check a value of laser diode
current and give a decision for deterioration.
7. Fundamental Deterioration Decision of Laser Pick-up
(1) If a voltage value in across Pin © of TP102 (+5V) and pin
@ (iop) of Unit (2U-2165) is V1, the value of laser diode
current "iop 1" can be found a formula
"op 1 = 44
Pi tee.
(2) If a "iop" exceeds + 10% compared with the IOP indication
on the laser pick-up nameplate, there is a fair chance for
deterioration when it is checked under a circumambient
temperature 23°C.
(3) When the circumambient temperature changes + 10°C, "iop
1" will change + 5%. The "iop 1" will also be changed by the
passage of time.
(4) In case of the above conditions taking into consideration and
performed the adjustment in proper way, if the HF level
across pin@ and across (HF) GND of TP102 in 2U-2165
becomes 0.6V or less values; or a jitter occurs great, the
laser pick-up may be deteriorated.
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