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5

This appliance is classified as a
CLASS 1 LASER product. The
CLASS 1 LASER PRODUCT
MARKING is located on the
rear exterior.

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

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

• Never reuse a disconnected chip component.
• Notice that the minus side of a tantalum capacitor may be

damaged by heat.

• 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.

The laser diode in the optical pick-up block may suffer electrostatic
break-down 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.

Never look into the laser diode emission from right above when
checking it for adjustment. It is feared that you will lose your sight.

0

0

0

This caution
label is located
inside the unit.

(US model only)

    After correcting the original service problem, perform the fol-
lowing safety checks 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.

    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). Leak-
age 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” indication is 0.75
V, so analog meters must have an accurate low-voltage scale.
The Simpson 250 and Sanwa SH-63Trd are examples of a pas-
sive VOM that is suitable. Nearly all battery operated digital
multimeters that have a 2V AC range are suitable. (See Fig. A)

µ

Ω

6

The special jig (J-2501-196-A) is useful for checking the waveform of the BD board. The names of terminals and the checking items to be
performed are shown as follows.

GND : Ground
I+3V : For measuring IOP (Check the deterioration of the optical pick-up laser)
IOP : For measuring IOP (Check the deterioration of the optical pick-up laser)
TE

: TRK error signal (Traverse adjustment)

VC

: Reference level for checking the signal

RF

: RF signal (Check jitter)

FE

: Focus error signal

7

The Iop value labeled on the optical pick-up can be recorded in the non-volatile memory. By recording the value, it will eliminate the need to
look at the value on the label of the optical pick-up. When replacing the optical pick-up or non-volatile memory (IC195 of BD board), record
the Iop value on the optical pick-up according to the following procedure.

Record Precedure:
1. While pressing the  l AMS L  knob and  x  button, connect the power plug to the outlet, and release the  l AMS L  knob and

x  button.

2. Rotate the  l AMS L  knob to display “[Service]”, and press the  YES  button.
3. Rotate the  l AMS L  knob to display “Iop Write” (C05), and press the  YES  button.
4. The display becomes “Ref=@@@.@” (@ is an arbitrary number) and the numbers which can be changed will blink.
5. Input the Iop value written on the optical pick-up.

To select the number : Rotate the  l AMS L  knob.
To select the digit

: Press the  l AMS L  knob.

6. When the  YES  button is pressed, the display becomes “Measu=@@@.@” (@ is an arbitrary number).
7. As the adjustment results are recorded for the 6 value. Leave it as it is and press the  YES  button.
8. “Complete!” will be displayed momentarily. The value will be recorded in the non-volatile memory and the display will become “Iop

Write”.

9. Press the  REPEAT  button to complete.

Display Precedure:
1. While pressing the  l AMS L  knob and  x  button, connect the power plug to the outlet, and release the  l AMS L  knob and

x  button.

2. Rotate the  l AMS L  knob to display “[Service]”, and press the  YES  button.
3. Rotate the  l AMS L  knob to display “Iop Read” (C26).
4. “@@.@/##.#” is displayed and the recorded contents are displayed.

@@.@ : indicates the Iop value labeled on the optical pick-up.
##.#

: indicates the Iop value after adjustment

5. To end, press the  l AMS L  button or  MENU/NO  button to display “Iop Read”. Then press the  REPEAT  button.

8

Before performing repairs, perform the following checks to determine the faulty locations up to a certain extent.
Details of the procedures are described in “5 Electrical Adjustments”.

• 5-6-2. Laser power check (see page 23)
• 5-6-3. Iop Compare (see page 23)
• 5-6-4. Auto Check (see page 24)

The criteria for determination above is intended merely to determine if satisfactory or not, and does not serve as the specified value for
adjustments.
When performing adjustments, use the specified values for adjustments.

The system microprocessor can be reset in the following procedure.
Use these procedure when the unit cannot be operated normally due to the overrunning of the microprocessor, etc.
Procedure :
Remove the short-pin attached to CN420, and then attach it again.