Sharp XL-520H Service Manual page 32

XL-520H,520E/CP-520,520E
• LCD indication error.
Is +5V applied to the pin 8 (VDD) of IC701?
Is +5V applied to the pin 38 (SYS STOP) of IC701?
Check the peripheral parts of IC701 and LCD701.
• Laser lighting failure.
Is +2.5V applied to the pin 42 of IC802?
Is approx. 2V applied to the collector of Q801.
Check CNW802. If it is normal, the optical pickup is faulty.
• Focus failure.
Does the optical pickup move up and down when the disc is
removed?
Is the following waveform ouput at the pin 11 (FEI) of IC801
when the disc is set?
Is the waveform shown above input at the pin 50 (SBAD) of
IC802?
IC801 is faulty.
Yes
Yes
No
Yes
Yes
Yes
Pin11
(FEI)
Pin16
(FSO)
Yes
Pin6
(SBAD)
Yes
Is +5.6V applied to the
No
emitter of Q704?
Yes
Check the pattern between Q704 and IC704.
Check the PWB pattern between the collector of Q702 and Q701.
No
Does the laser come on when pattern cut between pin 21 of IC801
No
and pin 42 of IC802.
Yes
Check the PWB pattern between IC701 and IC802 (BUCK/CCE/
BUS0~3)
Check the peripheral parts of IC801 and Q801. If it is normal, the
No
optical pickup is faulty.
Check as stated in item "FOCUS SERVO SAWTOOTH WAVE
No
FAILURE".
Check the periphery of IC801 and CNW802. is it normal?
No
Yes
The optical pickup is faulty.
Check the pattern between pin 6 of IC801 and pin 50 of IC802.
No
– 32 –
Check the pattern between
No
Q704 and CNS603.
Yes
The periphery of IC801 or
CNW802 is faulty.