Pioneer CDX-M8086ZT/E Service Manual page 40

CDX-M8086ZT ,M8086ZT-91,M8186ZT ,M8186ZT-91
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3 7 63 1515 0
5 Focus Bias Adjustment
•Purpose :
To adjust the focus servo reference so that the RF
waveform is an optimum.
•Symptoms of Mal-adjustment :
Difficulty in closing focus, poor playability.
•Measuring •Oscilloscope
Equipment / Jig
•Measuring Point •RFO
•Test Disc , Mode •ABEX TCD-784 (or SONY TYPE 4),
NORMAL MODE
•Adjustment Point •VR1003 (FE BIAS VR)
MAIN UNIT
RFO
TE
L 13942296513
Pull up the TOF terminal to the 5VA terminal with a 56kΩ resistor.
(This is in order to cancel lens offset in the tracking direction.)
Adjustment Procedure
1. Play track number 18.
2. Observe the RFO from REFO on an oscilloscope, and
adjust VR1003 (FE BIAS) so that the RF waveform is
maximum and eye pattern is optimum. (See wave-
form 10, 11)
3. Remove the pull-up resistor after completing adjust-
ment.
Check
After adjustment the RFO waveform should have an
amplitude of 1.7±0.65 Vpp (ABEX TCD-784 or SONY
www
TYPE 4)
.
40
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REFO
5VA
56kΩ
TOF
Oscilloscope
x ao u163
y
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http://www.xiaoyu163.com
2 9
8
Q Q
3 6 7 1 3 1 5
AC Mode Before adjustment
co
.
9 4 2 8
OK
Waveform 10
0 5 8 2 9 9 4 2 8
NG
Waveform 11
m
9 9
9 9