Toshiba SD-2550A, Service Manual

Page: 43 / 109

1-39
Disc kind misjudgement
(Initial setting is NG.)
Replace pickup head.
Lens cleaning.
Check IC502.
Are FE and RFSB
signals for each disc normal?
Check peripheral
circuit of IC605.
2-2
Y
N
Check laser operating current.
Check laser current.
I min lop I max
Check pins 13, 14
and 15 of IC502
serial bus.
Check peripheral
circuits of IC502,
Q501, Q502.
Check solder removal
of the short land for
laser diode protection.
Check FE and RFSB signal
lop I max lop I min
3
Check wiring for
pickup head.
Replace pickup
mechanism.
Y
Y
N
lop 200 mA
Laser operating current
DVD Iop
DVD Iop = Voltage between (E559 and E591) /10W
CD Iop = Voltage between (E536 and E591) /10W
CD Iop
min
20mA
20mA 35mA
45mA 60mA
80mA
typ max
CAUTION
The laser ray emitting out from the pickup head is very harmful to your eyes.
Keep your eyes from the objective lens at least 300mm distance during the pickup head operating.
When you perform solder removal work, please turn OFF a set power supply and perform the
ground of human body and a tool.
To turn on each laser diode forcibly, press the following buttons on the remote controller.
DVD LD: ZOOM, 0, 3, 0, ZOOM
CD LD: ZOOM, 0, 3, 1, ZOOM
After checked the laser current, press POWER or OPEN/CLOSE button to turn it off.
Fig. 1-3-4
Fig. 1-3-5
TP405 FE signal
1.65V
V : 500 mV/div
H : 2 ms/div
TP503 RFSB signal
DVD single (single-layer) disc
detection waveform
V : 500 mV/div
H : 2 ms/div
DVD dual (dual-layer) disc
detection waveform
V : 500 mV/div
H : 2 ms/div
CD disc
detection waveform
Fig. 1-3-6 Fig. 1-3-7 Fig. 1-3-8