Sharp XL-520W Service Manual page 33

• Focus servo sawtooth wave is not ouput.
Is +5V applied to the pin 20 (VCC) of IC801?
Yes
Is sawtooth wave output to the pin 16 (FSO) of IC801?
1~2sec
Yes
Is sawtooth wave obtained at the pin 33 of IC804 (as shown
above)?
Yes
Is sawtooth wave obtained between pins 30 and 31 of IC804
(as shown above)?
Yes
Is sawtooth wave obtained between pins 3 and 4 of CNW801
(as shown above)?
Yes
CNW801 connection failure or optical pickup failure.
• Spindle motor clv servo failure.
Does the spindle motor rotate?
Yes
Is the waveform shown above at the pin
24 of IC801.
Check the pattern between IC801 and
IC804.
Yes
Does the eye pattern appear at the pin 1 (RFO) of IC 801?
(Although the waveform is not clear.)
Yes
Is eye pattern Vp-p1.4V output at the pin 53 (RFI) of IC802?
Yes
Check the periphery pins 55~64 to IC802. If OK, IC802 is
faulty.
(excessively high speed rotation)
Yes
Check the pattern between pin 20 of IC801 and Q861.
No
Is the following waveform
No
shown below obtained?
Yes
(the sawtooth wave
fluctuates once to a side).
Check the periphery of pin 17 (COSC) of IC801.
If OK, IC801 is faulty.
Check pattern between pin 58 (CD STB) of IC701 and pin 36 of
No
IC804. If OK, signal line connection failure between pin 16 (FSO)
of IC801 and pin 33 of IC804.
Check the peripheral parts of IC804 and power line.
No
If OK, IC804 is faulty.
Check the pattern between IC804 and CNW801.
No
Is voltage oobtained for spprox
No
0.3 to 1.5 sec between the pins
24 and 25 of IC804 when the
CD test mode "STEP3" is
changed to "STEP4"
No
Check whether the pins 39 and
No
40 of IC802 is set to HIGH for
approx. 0.3 to 1.5 sec and then
pulse is obtained when the CD
test mode STEP3 is changed
to "STEP4"?
Yes
Check the periphery IC801. If OK, IC801 is faulty.
Check again that the objective lens of optical pickup is not
No
contaminated. If it is contaminated, clean. Check the periphery of
IC801 and CNW802. If OK, the optical pickup is faulty.
Check the PWB pattern and C841.
No
– 33 –
XL-520W/CP-520
Check R823 and R833 of
pins 43 and 44 of IC802.
No
If OK, IC801 is faulty.
Spindle motor failure or
wire breakage.
Yes
0.3~1sec
IC802 is faulty.
No
2V
0.3~1sec
VRO level