SECTION 5
ELECTRICAL ADJUSTMENTS
Precautions for AdjustmentFocus bias Check
1. Before beginning adjustment, set the equipment to serCondition: vice
mode.Y Hold the set in horizontal state.
After the completion of adjustment, be sure to reset the ser-
vice mode.Check Procedure:
For more information, see OService Mode (service program) �oscilloscope
(AC range)
on page 8.
2. Perform adjustments in the order given.MAIN board
3. Use YEDS-18 disc (Part No.: 3-702-101-01) unless otherwise2 k W
TP522 (RFO)+
indicated.TP520 (VC)�
4. Power supply voltage requirement: DC2.5 V in battery termi-
nal(See page 11)
VOLUME knob : Minimum
RESUME switch : OFF1. Set the equipment to service mode stop state. (See page 8.)
ESP switch: OFF2. Connect the oscilloscope to the test point TP522 (RFO) of the
AVLS switch: NORMALMAIN board.
HOLD switch: OFF3. Move the optical pick-up to the center by pressing the +
and = keys.
Before Beginning Adjustment4. Put the disc (YEDS-18).
Set the equipment to service mode (See page 8) and check the5. Press the ^ key.
following. If there is an error, repair the equipment.From focus searching, focus is turned ON while entering
CLV drawing-in mode. Tracking and sled are turned OFF.
Y Checking of the sled motor6. Press the PLAY MODE key. (Both tracking and sled are turned
1. Open the upper panel.ON.)
2. Press the + and = keys and check that the optical pick-7. Check the oscilloscope waveform is as shown below.
up can move smoothly without sluggishness or abnormal noiseA good eye pattern means that the diamond shape (A) in the
in innermost periphery n outermost periphery n innermostcenter of the waveform can be clearly distinguished.
periphery
+ :The optical pick-up moves outwardly.RF SIGNAL REFERENCE WAVEFORM (EYE PATTERN)
= :The optical pick-up moves inwardly.
VOLT/DIV : 200 mV (With the 10:1 probe in use)
Y Checking of focus searching TIME/DIV : 500 ns
1. Open the upper panel.
2. Press the ^ key. (Focus searching operation is activated
continuously.)
3. Check the object lens of the optical pick-up for smooth up/
down motion without sluggishness or abnormal noise.RF level
1.0 ? 0.2V
4. Press the p key.
Check that focus searching operation is deactivated. If not,
again press the p key slightly longer.
VCC AdjustmentTo watch the eye pattern, set the oscilloscope to AC range and
increase the vertical sensitivity of the oscilloscope for easy watch-
Adjustment Procedure:ing.
digital voltmeter
(DC range)
8. Stop revolving of the disc motor bp key pressing the y.
MAIN board9. After the completion of adjustment, reset service mode. (See
TP401 (VCC)+page 8.)
�
(See page 11)Check Location: MAIN Board (See page 11.)
1. Set the equipment to service mode stop state. (See page 8.)
2. Connect the digital voltmeter to TP401 (VCC) of the MAIN
board.
3. Adjust RV401 on the MAIN board so that the reading on digi-
tal voltmeter goes 2.75? 0.05 V.
4. After the completion of adjustment, reset service mode. (See
page 8.)
Adjustment Location: MAIN board (See page 11)
� 9 � |
ACEC
