Panasonic Ju4755 Service Manual

r 
/ 
r / 
1/ 
1 
r  
\, 
Fig. 9.2 
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1-. / I 
1 / -
A  B  
/ i J 
V  -
V  L-V 
-
Radial Alignment  Waveforms (CATS EYE) 
A> B 
B>A 
_l -A _ A -S 
)( 100 
II lOa 
Nota: Sides 0 and 1 a,.. adjusted to agree at the actofY. If they disagree, adju them to meet the specifintions of Table 8.1 
• DAD (Dynamic Alignment Diskette) 3.5-inch 
(4) Watch  the output waveforms for sides 0 and 1.  The y should  appear as shown in Fig.  9.3. 
(S) Measure the timing level s Al to A4 and  81 to 84 in Fig.  9.3,  and...

9.6 Azimuth Verification 
(1 ) Insert an alignment diskette.  Seek  to the  trac k specifie d in the azimu th column of Table B.l . 
(2)  Set the 
oscillosco pe in the same  conditions as in B.3,  and set  horizontal deflection to 0 ,5 ms /division. 
(3)  Meas u
re as shown below . 
(4)  Confirm that the measured value meets the specificat ion s in the azimuth  column  of Table  B.l, 
B c 
B C c o A B 
A 0 
A 
:! 
A)!,m u(h  0  wave form$ 
CaseofB> C C_ofB( (AI C- B Azimurh ,. ---x (AI C- A 
9.7 Index...

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9 .8  Track 00 Sen sor  Adjustment 
(1 ) Set the oscilloscope as follows. 
Set horizontal deflection  to  1 mYdivision . 
CH1 EX T 
S.2S-i nch TP-8 Tp·12 
3.5·in ch zp SP 
(21 Step between specified  tracks at in the FLAG 0 item ofTable 8.1 (Turn the seek delay  switch on the exer ciser to adjust  12 
ms seek.) 
(3) loosen  the track 0 sensor  screw and adjust until the waveform  on the oscilloscope appears  as shown  in Fig.  9 .6 . 
A 
--+----sv 
'---------~------GND 
ADJUST A :B TO...

(4) Write If. 
(5) A read walle form is displayed on the oscilloscope as shown  in Fig . 9.7. 
(6) Confirm  if it  1atisfies the villue as shown in Fig . 8.1. 
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PART .11 
11.  REMOVALS  AND INSTALLATIONS 
11.1 P C B Removal and Installation (See Fig. 11.1) 
(1)  Remove the two printed circuit board 
mounting screws . 
(2)  Disconnect the connectors (J3 CON, J4 CON, 
J6 CON,)5  CON,J8CON) from the printed 
circuit board. 
(3)  Remove the printed circuit  board by sliding it 
aslant. 
(4) To reinstall , reverse the above  procedure . 
(5) Readjustment is not  necessary after printed 
circuit board replacement . 
Printed Circuit Board 
8 
Fig_ 11.1  Pri...

11.4 Collet Assembly Removal, Inst allation. and 
Adjustment  (See Fig.11.4) 
(1) Remove the Cartridge  Guide Assembly  as 
desc
ribed in 11. 7 
(2) Remove the lifter  spring  from the lifter. 
(3) Remove the E-ring  from the lifter shaft. 
(4) Remove the lifter from the Cartridge  Guide. 
(5) Remove the Collet Assembly  from the Guide 
shaft. 
(6) Reverse the above proced ure to reinstall. 
(7) After  reinstallation,  perform collet assembly 
center adjustment. 
(B) Collet assembly center adjustment....

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11.6 Write Protect Sensor/Index Detector  Assembly 
Removal 
and Installation  (See Fig. 11.6) 
(1) Remove the front plate as described in 11.2. 
(2) Remove the write protect senso r mou nting  g 
screw 
and index detector mounting  screw 
respectively. 
(3) Remove the wr ite protect sensor/index 
detector assembly. 
(4) Reverse the above  procedure to reinsta ll. 
(5) When reinstalling the write protect sensor, 
exercise 
care so that the leads  and write 
protect sensor will not project  from...

11.8 Stepper Motor Assembly  Removal and 
Installation (See Fig. 11.8) 
(1) Remove the insulating paper and shiel d 
plate. 
(2) Remove the track 00 sensor as described in 
11.3 . 
(3) Remove the two (M2 x 4) actuator screws that 
fasten the actuator to the carriage  arm 
assembly . 
(4)  Remove 
the two (M3 x 6) stepper motor 
asse mbly mounting  screws and then the 
stepper·motor. 
(5) Reverse the above procedure  to r einstall. 
(6) After  reinstalla tion , perform  limiter chec k as 
i n 
9 .10 and...

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1.10 Drive  Motor  Removal and Installation 
(See Fig.11.10) 
(1) Remove the printed circuit board as 
described in 11.1. 
(2)  Remove the insulating paper and shield 
plate. 
(3) Remove the front plate as  described in 11.2 . 
(4)  Remove the write protect senso r as describ ed 
in 11.6. 
(5)  Remove the cartridge guide assembly as 
described in 11.7. 
(6)  Remo ve 
the three drive motor mounting 
screws and take off the drive motor from the 
base . 
(7)  Disconnect the drive motor...

12. TEST POINTS 
Printed  Circuit Board 
(Top view) 
GND lNTTRK00 
Vout(-) Vout(+) + READ DATA 
STEP 
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