CMT-EX1, HCD-EX1 - Sony Audio Service Manual (repair manual). Page 13

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13
Note:
1. CD Block is basically constructed to operate without adjustment.
Therefore, check each item in order given.
2. Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.
3. Use an oscilloscope with more than 10M
Ω
 impedance.
4. Clean the object lens by an applicator with neutral detergent when
the signal level is low than specified value with the following
checks.
S Curve Check

Procedure :
1. Connect the oscilloscope to test points TP (FE) and TP (VC).
2. Connect TP (FEI) and TP (VC) of the MAIN board with lead
wires.
3. Press the  
1/u  button to turn the set ON.
4. Press the  
^  button, load and eject the disc (YEDS-18) to
perform focus search.
5. Check the symmetry and peak to peak level of the oscilloscope
waveform (S curve) at this time.
S-curve waveform
6. After check, remove the lead wire connected in step 2.
Note:

 • Try to measure several times to make sure than the ratio of
A : B or B : A is more than 10 : 7.
• Take sweep time as long as possible and light up the bright-
ness to obtain best waveform.
Checking Location : MAIN board
RF Level Check

Procedure :
1. Connect oscilloscope to test point TP (RF) and TP (VC) on MAIN
board.
2. Press the  
1/u  button to turn the set ON.
3. Put disc (YEDS-18) in and playback 5track.
4. Confirm that oscilloscope waveform is clear and check RF sig-
nal level is correct or not.
oscilloscope
MAIN board
TP (FE)
TP (VC)
+
–
symmetry
A
B
Within 3.8 
±
 1 Vp-p
oscilloscope
MAIN board
TP (RF)
TP (VC)
+
–
VOLT/DIV : 200mV
TIME/DIV : 500ns
level : 1.2 
±
 0.2 Vp-p
0V
Center of the waveform
B
Symmetry
A (DC voitage)
level : 1.3 
±
       Vp-p
+0.6
–0.7
oscilloscope
MAIN board
TP (TE)
TP (VC)
+
–
Note:
Clear RF signal waveform means that the shape “
◊
” can be
clearly distinguished at the center of the waveform.
RF signal waveform
Checking Location : MAIN board
E-F Balance (1 Track Jump) check

Procedure:
1. Connect oscilloscope to test point TP (TE) and TP (VC) on MAIN
board.
2. Press the  
1/u  button to turn the unit ON.
3. Put disc (YEDS-18) in to play the number five track.
4. Press the  
^  button, to pause.
5. Check the level (B) of the oscilloscope's waveform and the DC
voltage (A) of the center of the Traverse waveform.
Confirm the following:
• A/B x 100 = less then ± 22 (%)
• B = 1.3 ± 
  Vp-p
1 track jump waveform
SECTION  4
ELECTRICAL ADJUSTMENT
+0.6
–0.7
Checking Location : MAIN board

[ MAIN BOARD ] — SIDE A —
TP
(VC)
TP
(FEI)
TP
(RF)
TP
(FE)
TP
(TE)
IC303
IC301
Display
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