Sanyo FISHER DVD-1500 Service Manual page 12

CHECK FLOW AND TROUBLE SHOOTING
(Disk identification/mode setting)
Turn on power.
Tray close/closed
"LASER" lights.
Pickup returns.
8/12 cm identification
Identifies disk
Sets mode
INIT processing of TC9461
Laser off 20 ms
Laser on.
Focus search
Automatic alignment
Tracking balance
Focus balance
Focus gain
Tracking gain
RF gain
Disk identification/mode setting
Problem/symptom Check
Check that disk identification is correct.
Not focusable Check that FOO waveform is normal or smooth.
1 (disk error) Error 21 Check that peak value of detection pulse (S curve) is correct.
Check that lens up/down operation is normal.
Check that lens is free from dirt or stain.
2 Not focusable Check LASER current (R5100).
(disk error) Error 21 Compare it with that indicated close to pickup's serial number.
3 No focus search FLGC TP716 (IC900 80pin)
4 No focus search Check RFO (IC501 pin 28).
Wrong ROM
5 Inactive Check LCSW
Repair CD/*DVD (DVD/*CD).
An extract from "GENERAL FLOW"
Raises lens with each IC
in CD mode
Measures FE level (a)
Measures number of FE pulses;
one or two
Lowers lens with each IC
in DVD mode
Rotates at a speed of two times that of CD
Measures FE level (b)
FE pulse 1 or 2
1
(b) / (a) > 1.5
YES
one-layer DVD
Sets one-layer DVD circuit to
pickup mode.
2
NO
Sets CD circuit to Sets two-layer DVD circuit to
pickup mode.
Waveform
2
(34) ~ (38)
(2) ~ (4)
- 11 -
Two-layer DVD
pickup mode
Schematic diagram Reference data
F
F
F
F
Voltage tables
(7) & (8)