D-E551/E555/E556CK
SECTION 5
ELECTRICAL ADJUSTMENTS
Precautions for AdjustmentFocus bias CheckFocus/Tracking Gain AdjustmentThe waveforms are those measured with the oscilloscope set asAdjustment and Checking Location:
1. Before beginning adjustment, set the equipment to serCondition: viceA servo analayzer is necessary in order to perforshom this adjustmentwn below.
mode.Y Hold the set in horizontal state.exactly.Y VOLT/DIV: 500 mV� MAIN BOARD (Side A) �
After the completion of adjustment, be sure to reset the ser-Y TIME/DIV: 5 ms
However, this gain has a margin, so even if it is slightly off,
vice mode.Check Procedure:
there is no problem. Therefore, do not perform this adjustment.
For more information, see OService Mode (service program) �oscilloscope Y Waveform when tracking gain is lowered.
on page 8.(AC range)Focus/tracking gain determines the optical pick-up folloFundamental ww-up rela-ave appears. (large waves)
2. Perform adjustments in the order given.tive to mechanical noise and mechanical shock when the 2-axis
MAIN board
3. Use YEDS-18 disc (Part No.: 3-702-101-01) unless otherwise2 k Wdevice operates. However, as these reciprocate, the adjustment is
TP522 (RFO)+��� 0 V
indicated.at the point where both are satisfied.
TP520 (VC)�
4. Power supply voltage requirement: DC2.5 V in battery termi-Y When gain is rased, the noise when 2-axis device operates in-
nal(See page 11)crease.Fig. 1
VOLUME knob : MinimumY When gain is lowered, it is more susceptible to mechanical shock
RESUME switch : OFF1. Set the equipment to service mode stop state. (See page 8)and skipping occurs more easily.Y Waveform when fundamental wave disappears. (no large waves)
ESP switch: OFF2. Connect the oscilloscope to the test point TP522 (RFO) on theThis adjustment has to be performed upon replacing any of the
AVLS switch: NORMALMAIN board.following parts.
��� 0 V
HOLD switch: OFF3. Move the optical pick-up to the center by pressing the +Y Optical pick-up
and = keys.Y RV503 (Focus gain VR)
Before Beginning Adjustment4. Put the disc. (YEDS-18)Y RV502 (Tracking gain VR)Fig. 2
Set the equipment to service mode (See page 8) and check the5. Press the ^ key.
Normally, be sure not to move RV503 (focus gain VR) and
following. If there is an error, repair the equipment.From focus searching, focus is turned ON while enteringY Waveform with no traverse waveform during 100 track jump.
RV502 (tracking gain VR).
CLV drawing-in mode. Tracking and sled are turned OFF.(Brake application is smooth because of adjustment)
Y Checking of the sled motor6. Press the PLAY MODE key. (Both tracking and sled are turned
1. Open the upper panel.ON)Adjustment procedure:
2. Press the + and = keys and check that the optical pick-7. Check the oscilloscope waveform is as shown belo� Focus Gain Adjustment �w.
up can move smoothly without sluggishness or abnorA good emal noiseye pattern means that the diamond shape (A) in theThis adjustment is not performed.��� 0 V
in innermost periphery n outermost periphery n innermostcenter of the waveform can be clearly distinguishedIf focus gain .VR RV503 is turned, set to mechanical center.
peripheryAdjustment Location: MAIN Board (See page 11)
+ : The optical pick-up moves outwardly.RF Signal Reference Waveform (Eye Pattern)
= : The optical pick-up moves inwardly.� Tracking Gain Adjustment �
VOLT/DIV : 200 mV (With the 10:1 probe in use) (perform at normal operation)
100 track jump waveformTP522
Y Checking of focus searching TIME/DIV : 500 ns
(RFO)
1. Open the upper panel.oscilloscopeFig. 3
(DC range)TP401
2. Press the ^ key. (Focus searching operation is activated con-
(VCC)
tinuously)Y Waveform with traverse waveform during 100 track jump.
MAIN board
3. Check the object lens of the optical pick-up for smooth up/10 k W(Brake application is poor because of adjustment)
RF levelTP (TE)
down motion without sluggishness or abnormal noise.+
0.8 to 1.2 Vp-pTP520 (VC)�
4. Press the p key.RV401
Check that focus searching operation is deactivated. If not,0.0022 ?F(See page 11)(VCC)
again press the p key slightly longer.
��� 0 V
1. Place the optical pick-up level, horizontally. (If the optical
To watch the eye pattern, set the oscilloscope to AC range and
VCC Adjustmentpick-up is not level, the 2-axis device will be weighted and
increase the vertical sensitivity of the oscilloscope for easy watch-
Adjustment Procedure:adjustment cannot be done)
ing.
digital voltmeter2. Connect the oscilloscope to TP (TE) and TP520 (VC) on the
(DC range)
MAIN board.
8. Stop revolving of the disc motor by pressing the p key.
MAIN board3. Set the disc (YEDS-18) and press the ^ key.
9. After the completion of adjustment, reset service mode. (See
4. Turn RV502 slightly clockwise (tracking gain drops) and ob-
page 8)
TP401 (VCC)+
tain a waveform with a fundamental wave (wavefor100 track jumpm has large
�traverse waveform
waveform
(See page 11)Check Location: MAIN Board (See page 11)waves) as in Figure 1.
5. Turn RV502 slowly counterclockwise (tracking gain rises) untilFig. 4
1. Set the equipment to service mode stop state. (See page 8)the fundamental wave disappears (no large waves) as in Fig-
RV503
2. Connect the digital voltmeter to TP401 (VCC) on the MAINure 2.Adjustment Location: MAIN Board (See page 11)
Focus Gain
board.6. Set RV502 to the position about 30u counterclockwise form
Adjustment
3. Adjust RV401 on the MAIN board so that the reading on digi-the position obtained in step 5. If RV502 contact point is moreTP520
tal voltmeter goes 2.77 V.than 90u counterclockwise from mechanical center, tracking(VC)TP
Specifications: 2.75 V to 2.8 Vgain is too high. In this case, readjust from step 4.(TE)RV502
4. After the completion of adjustment, reset service mode. (See7. Press + or = key and observe the 100 track jump wave-Tracking Gain
page 8)form. Check that no traverse waveform a+ppears for both Adjustment
or = directions. (See Figures 3 and 4)
Adjustment Location: MAIN Board (See page 11)It is acceptable if the traverse waveform appears only now and
then, but if it appears constantly, raise tracking gain slightly
and check step 7 again.
8. Check that there is not abnormal amount of operation noise
(white noise) from the 2-axis device. If there is, tracking gain
is too high, readjust starting with step 4.
� 9 �� 10 �� 11 � |
ACEC
SONY
