Toshiba ntdvt006bk ユーザーズマニュアル
tween the 2 boards occur during low transi-
tions.
tions.
4. Using pin 7 as the reference, monitor the
clock signal on pin 6 of CN602. There are
eleven negative clock pulses during 1 low
cycle of the FSTBX signal.
eleven negative clock pulses during 1 low
cycle of the FSTBX signal.
5. Check the DSPSO signal on pin 5 of CN602.
This is the serial information going to the
front panel.
front panel.
6. Check the DSPSI signal on pin 4 of CN602.
This is the serial information coming from the
front panel. Again, notice how it changes
when a disc is playing.
front panel. Again, notice how it changes
when a disc is playing.
7. If the signals are missing or improper, remove
power from the player, and gently pull the
flex cable out of CN602.
flex cable out of CN602.
8. Measure the clock signal, the DSPSO signal,
and the DSPSI signal using the FSTBX signal
as a reference. All of the signals are present
except the DSPSI signal.
as a reference. All of the signals are present
except the DSPSI signal.
Laser Checks
1. Check the DVD RF signal at TP502. The
signal should look like a normal eye pattern
with a peak to peak voltage of about 2.7 volts
or higher. This peak to peak measurement
varies from player to player and decreases as
the laser ages.
with a peak to peak voltage of about 2.7 volts
or higher. This peak to peak measurement
varies from player to player and decreases as
the laser ages.
2. Check the differential RF signals at pins 16
and 17 of CN501. They should be about 0.5
volts peak to peak.
3. Clean the objective lens with a cotton swab
and alcohol if the signal is low.
4. Recheck the RF signal, and if it is still low
replace the laser slide assembly.
5. Another way to check the power of the laser
is with a laser power meter. A new laser
should measure about 0.2 milliwatts.
should measure about 0.2 milliwatts.
6. You can also visually check the laser during
power on. However, be sure not to look
directly into the laser.
directly into the laser.
7. The RF signal for a CD is checked at TP501.
It also looks like normal eye pattern, but its
frequency is lower than that of the DVD.
Normally it is about 1.6 volts peak to peak.
frequency is lower than that of the DVD.
Normally it is about 1.6 volts peak to peak.
Focus and Tracking Checks
1. For a focus problem, check the focus error
signal at TP504. Cycle the power off then on
to see the operation of the focus error signal.
Gently tap the side of the player to check the
operation of the signal. If the signal is miss-
ing or improper, the main board is most likely
at fault.
to see the operation of the focus error signal.
Gently tap the side of the player to check the
operation of the signal. If the signal is miss-
ing or improper, the main board is most likely
at fault.
2. Play a CD and check the focus error signal at
TP504.
3. For a tracking problem, check the tracking
error signal at TP507. Cycle the power off
then on to see the operation of the tracking
error signal. Gently tap the side of the player
then on to see the operation of the tracking
error signal. Gently tap the side of the player
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