FST-ZX9, HCD-ZX9, LBT-ZX9 - Sony Audio Service Manual (repair manual). Page 3

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Use of controls or adjustments or performance of procedures
other than those specified herein may result in hazardous
radiation exposure.

The laser diode in the optical pick-up block may suffer electrostatic
breakdown because of the potential difference generated by the
charged electrostatic load, etc. on clothing and the human body.
During repair, pay attention to electrostatic break-down and also
use the procedure in the printed matter which is included in the
repair parts.
The flexible board is easily damaged and should be handled with
care.

Notes on Chip Component Replacement
• Never reuse a disconnected chip component.
• Notice that the minus side of a tantalum capacitor may be

damaged by heat.

Flexible Circuit Board Repairing
• Keep the temperature of soldering iron around 270

°C during

repairing.

• Do not touch the soldering iron on the same conductor of the

circuit board (within 3 times).

• Be careful not to apply force on the conductor when soldering

or unsoldering.

UNLEADED SOLDER
Boards requiring use of unleaded solder are printed with the lead
free mark (LF) indicating the solder contains no lead.
(Caution: Some printed circuit boards may not come printed with

the lead free mark due to their particular size)

Unleaded solder has the following characteristics.
• Unleaded solder melts at a temperature about 40 

°C higher than

ordinary solder.
Ordinary soldering irons can be used but the iron tip has to be
applied to the solder joint for a slightly longer time.
Soldering irons using a temperature regulator should be set to about
350 

°C.

Caution: The printed pattern (copper foil) may peel away if the

heated tip is applied for too long, so be careful!

• Strong viscosity

Unleaded solder is more viscou-s (sticky, less prone to flow) than
ordinary solder so use caution not to let solder bridges occur such
as on IC pins, etc.

• Usable with ordinary solder

It is best to use only unleaded solder but unleaded solder may also
be added to ordinary solder.

This appliance is
claassified as a CLASS 1
LASER product. This
label is located on the
rear exterior.

NOTES ON LASER DIODE EMISSION CHECK
The laser beam on this model is concentrated so as to be focused on
the disc reflective surface by the objective lens in the optical pick-
up block. Therefore, when checking the laser diode emission,
observe from more than 30 cm away from the objective lens.

Laser component in this product is capable
of emitting radiation exceeding the limit for
Class 1.

1.5 k

Ω

0.15 

µ

F

AC
voltmeter
(0.75 V)

To Exposed Metal
Parts on Set

Earth Ground

SAFETY  CHECK-OUT (US MODEL)
After correcting the original service problem, perform the follow-
ing safety check before releasing the set to the customer:
Check the antenna terminals, metal trim, “metallized” knobs, screws,
and all other exposed metal parts for AC leakage.
Check leakage as described below.

LEAKAGE  TEST
The AC leakage from any exposed metal part to earth ground and
from all exposed metal parts to any exposed metal part having a
return to chassis, must not exceed 0.5 mA (500 microampers.).
Leakage current can be measured by any one of three methods.
1. A commercial leakage tester, such as the Simpson 229 or RCA

WT-540A. Follow the manufacturers’ instructions to use these
instruments.

2. A battery-operated AC milliammeter. The Data Precision 245

digital multimeter is suitable for this job.

3. Measuring the voltage drop across a resistor by means of a

VOM or battery-operated AC voltmeter. The “limit” indica-
tion is 0.75 V, so analog meters must have an accurate low-
voltage scale. The Simpson 250 and Sanwa SH-63Trd are ex-
amples of a passive VOM that is suitable. Nearly all battery
operated digital multimeters that have a 2 V AC range are suit-
able.  (See Fig. A)