I No Start-Up And Dvd Transport Problems; Power-On Start-Up Sequence - Where Is The Problem - Panasonic SAHT730 - DVD THEATER RECEIVER Technical Manual

I No Start-Up and DVD Transport Problems

Model: SA-HT730 / HT930. Since this unit normally starts in DVD mode, start-up
symptoms are often caused by DVD transport problems – A failure in the DVD
transport stops the start up.
Servicing the DVD section is divided into 6 groups (pick and choose what you need):
1. Power-On Sequence
2. Sensors, Belts and Motor Location
3. Simulated Sensor Failure Symptoms 6. Sensor testing
Start with the power-on sequence. The power-on sequence is important for
identifying the section that does not start. Compare the sequence in the defective
unit to the correct sequence listed below in table 1. The step where the unit stops
working is where the problem is (or in the step just before). Testing the sensors is
the next diagnostic step (section 6) if the transport works but behaves out of
sequence. Section 2 locates the sensors. However access to the sensors for testing
is tricky but the trick is revealed in section 4 - tray removal. After repairs, section 5
shows how to align the gears for reassembly.
1. Power-On Start-Up Sequence – Where is the problem?
After AC is disconnected, the unit always powers on into the DVD operation mode.
Step Time
1. 0 AC input. Unit off.
2. 0 Press Power button
3. 1 sec
4. 4 sec Micro IC8001 controls laser
assembly via cable to
CN2004. See table 2.
5. 5 sec Loading motor moves the
Tray in (if S9001 is not open)
and into the disc unchucked
position using two loading
sensors.
No movement will occur if the
transport is already in this tray
in unchucked position.
6. 8 1. Disc Tray motor rotates.
sec. Slow rotation is first.
2. Detection of discs on platter
/ tray.
7. 17 Tray motor stops at original
disc slot.
SA-HT730 / SAHT930
4. Tray Removal for Diagnostic Access
5. Tray Installation (after Repairs)
SA-HT730 / HT930 Power ON sequence
Operation
None
"Hello"
appears
"INIT" appears
"Please Wait"
"Please Wait"
" No Disc"
Table 1
Display
Red light over pwr button
(standby).
Disc # 1-5 light in sequence.
All disc numbers 1-5 light.
Disc proof sequence is followed *
see table 2.
Two loading sensors are used:
1. S9001 = contacts open / tray
closed. Contacts are open if the
Tray is in.
2. Q9001 at CN2011/6 = 0Vdc =
non-clamped position (tray
rotation is possible when the
disc assembly is unclamped.)
1. S9102 detects tray motor gear
rotation.
2. Q9103 detects each disc when
the disc blocks the Q9103 light.
S9101 also detects tray rot.
position.
5
Proof