46
CDX-MG6346ZH,MG6446ZH
6. ADJUSTMENT
CHECKING THE GRATING AFTER CHANGING THE PICKUP UNIT
• Note :
The grating angle of the PU unit cannot be adjusted after the PU unit is changed. The PU unit in the CD mecha-
nism module is adjusted on the production line to match the CD mechanism module and is thus the best adjusted
PU unit for the CD mechanism module. Changing the PU unit is thus best considered as a last resort. However, if
the PU unit must be changed, the grating should be checked using the procedure below.
• Purpose :
To check that the grating is within an acceptable range when the PU unit is changed.
• Symptoms of Mal-adjustment :
If the grating is off by a large amount symptoms such as being unable to close tracking, being unable to perform
track search operations, or taking a long time for track searching.
• Method :
• Measuring Equipment
• Oscilloscope, Two L.P.F.
• Measuring Points
• E, F, REFOUT
• Disc
• ABEX TCD-784
• Mode
• TEST MODE
• Checking Procedure
1. In test mode, load the disc and switch the 5V regulator on.
2. Using the TRK+ and TRK- buttons, move the PU unit to the innermost track.
3. Press key 3 to close focus, the display should read "91". Press key 2 to implement the tracking balance adjust-
ment the display should now read "81". Press key 3 4 times. The display will change, returning to "81" on the
fourth press.
4. As shown in the diagram above, monitor the LPF outputs using the oscilloscope and check that the phase differ-
ence is within 75° . Refer to the photographs supplied to determine the phase angle.
5. If the phase difference is determined to be greater than 75° try changing the PU unit to see if there is any
improvement. If, after trying this a number of times, the grating angle does not become less than 75° then the
mechanism should be judged to be at fault.
• Note
Because of eccentricity in the disc and a slight misalignment of the clamping center the grating waveform may be
seen to "wobble" ( the phase difference changes as the disc rotates). The angle specified above indicates the aver-
age angle.
• Hint
Reloading the disc changes the clamp position and may decrease the "wobble".
100k
Ω
390pF
100k
Ω
390pF
E
REFOUT
F
Xch
Ych
Oscilloscope
L.P.F.
L.P.F.
E
F
REFOUT
REFOUT
CD CORE UNIT(SERVO UNIT)
Summary of Contents for CDX-MG6346ZH/ES
Page 4: ...4 CDX MG6346ZH MG6446ZH 2 2 EXTERIOR ...
Page 6: ...6 CDX MG6346ZH MG6446ZH 2 3 CD MECHANISM ...
Page 13: ...13 CDX MG6346ZH MG6446ZH 5 6 7 8 5 6 7 8 D C B A A A b A EXTENSION UNIT ...
Page 14: ...14 CDX MG6346ZH MG6446ZH 1 2 3 4 1 2 3 4 D C B A 1 A a A b D CD CORE UNIT STS UNIT A a ...
Page 15: ...15 CDX MG6346ZH MG6446ZH 5 6 7 8 5 6 7 8 D C B A A a A b B 2 B KEYBOARD UNIT A a ...
Page 16: ...16 CDX MG6346ZH MG6446ZH 1 2 3 4 1 2 3 4 D C B A A a A b 1 A EXTENSION UNIT A b ...
Page 17: ...17 CDX MG6346ZH MG6446ZH 5 6 7 8 5 6 7 8 D C B A A a A b 2 A b ...
Page 27: ...27 CDX MG6346ZH MG6446ZH 1 2 3 4 1 2 3 4 D C B A CN701 CN901 EXTENSION UNIT SIDE B A A B D ...
Page 29: ...29 CDX MG6346ZH MG6446ZH 1 2 3 4 1 2 3 4 D C B A SIDE B KEYBOARD UNIT B B ...
Page 31: ...31 CDX MG6346ZH MG6446ZH 1 2 3 4 1 2 3 4 D C B A CD CORE UNIT SERVO UNIT SIDE B C C ...
Page 33: ...33 CDX MG6346ZH MG6446ZH 1 2 3 4 1 2 3 4 D C B A CD CORE UNIT STS UNIT SIDE B D D ...
Page 35: ...M M4 CARRIAGE 1 12 D CN301 35 CDX MG6346ZH MG6446ZH 5 6 7 8 5 6 7 8 D C B A E C ...
Page 37: ...1 41 G CN801 37 CDX MG6346ZH MG6446ZH 1 2 3 4 1 2 3 4 D C B A MOTOR PCB A F SIDE B F D ...
