Philips Q548.1E Service Manual page 28

EN 28 5. Q548.1E LA
Important remark:
For all errors detected by MIPS which are fatal =>
rebooting of the TV set (reboot starts after LAYER 1 error
blinking), one should short the solder paths at start-up from
the power OFF state by mains interruption and not via the
power button to trigger the SDM via the hardware pins.
• Transmit the commands "MUTE" - "062500" - "OK"
with a normal RC. The complete error buffer is shown.
Take notice that it takes some seconds before the blinking
LED starts.
• Transmit the commands "MUTE" - "06250x" - "OK"
with a normal RC (where "x" is a number between 1
and 5). When x = 1 the last detected error is shown, x = 2
the second last error, etc.... Take notice that it takes some
seconds before the blinking LED starts.
5.7 Protections
5.7.1 Software Protections
Most of the protections and errors use either the stand-by
microprocessor or the MIPS controller as detection device.
Since in these cases, checking of observers, polling of ADCs,
and filtering of input values are all heavily software based,
these protections are referred to as software protections.
There are several types of software related protections, solving
a variety of fault conditions:
• Protections related to supplies: check of the 12V, +5V,
+3V3 and 1V2.
• Protections related to breakdown of the safety check
mechanism. E.g. since the protection detections are done
by means of software, failing of the software will have to
initiate a protection mode since safety cannot be
guaranteed any more.
Remark on the Supply Errors
The detection of a supply dip or supply loss during the normal
playing of the set does not lead to a protection, but to a cold
reboot of the set. If the supply is still missing after the reboot,
the TV will go to protection.
Protections during Start-up
During TV start-up, some voltages and IC observers are
actively monitored to be able to optimise the start-up speed,
and to assure good operation of all components. If these
monitors do not respond in a defined way, this indicates a
malfunction of the system and leads to a protection. As the
observers are only used during start-up, they are described in
the start-up flow in detail (see section
up).
5.7.2 Hardware Protections
The only real hardware protection in this chassis appears in
case of an audio problem e.g. DC voltage on the speakers. The
audio protection circuit pulls the "supply-fault" low and the tv set
will blink LAYER 1 error = 2 or in SDM, LAYER 2 error = 19.
Be very careful to overrule this protection via SDM (not to
cause damage to the Class D audio amplifier). Check audio
part first before activating via SDM. In case one of the
speakers is not connected, the protection can also be
triggered.
Repair Tips
• It is also possible that the set has an audio DC protection
because of an interruption in one or both speakers (the DC
voltage that is still on the circuit cannot disappear through
the speakers).
Caution: (Dis)connecting the speakers during the ON
state of the TV can damage the audio amplifier.
2009-Apr-03
Service Modes, Error Codes, and Fault Finding
5.3 Step by step Start-
5.7.3 Important remark regarding the blinking LED indication
As for the blinking LED indication, the blinking LED of layer 1
error displaying can be switched "off" by pushing the power
button on the keyboard.
This condition is not valid after the set was unpowered (via
mains interruption). The blinking LED starts again and can only
be switched "off" by unplugging the mains connection.
This can be explained by the fact that the MIPS can not load
the keyboard functionality from software during the start-up and
does not recognise the keyboard commands at this time.
5.8 Fault Finding and Repair Tips
Read also section "5.5 Error
Information".
5.8.1 Ambilight
Due to degeneration process of the AmbiLights, there can be a
difference in the colour and/or light output of the spare
ambilight module in comparison with the originals ones
contained in the TV set. Via ComPair, the light output can be
adjusted.
5.8.2 CSM
When CSM is activated and there is a USB stick connected to
the TV, the software will dump the complete CSM content to the
USB stick. The file (Csm.txt) will be saved in the root of the USB
stick. If this mechanism works it can be concluded that a large
part of the operating system is already working (MIPS, USB...)
5.8.3 Exit "Factory Mode"
When an "F" is displayed in the screen's right corner, this
means the set is in "Factory" mode, and it normally
happens after a new SSB is mounted. To exit this mode, push
the "VOLUME minus" button on the TV's local keyboard for 10
seconds (this disables the continuous mode).
Then push the "SOURCE" button on the TV's local keyboard
for 10 seconds until the "F" disappears from the screen.
5.8.4 DC/DC Converter
Introduction
• The best way to find a failure in the DC-DC converters is to
check their starting-up sequence at "power-on via the
mains cord", presuming that the stand-by microprocessor
is operational.
• If the input voltage of DC-DC converters is around 12.7 V
(measured on decoupling capacitors 2107 and 2123 and
the enable signals are "low" (active), then the output
voltages should have their normal values. The +12V and
+5VPOD supplies start-up first (enabled by PODMODE
signal from the stand-by microprocessor). There is a
supplementary condition for 12V to start-up: if the +5V-
POD does not start up due to a local defect, then +12V will
not be available as well. The +5V-ON supply is enabled by
the ONMODE signal (coming also from the stand-by
microprocessor). The +1V2 supply starts up when the
+12V appears, then at least 100 ms later, the +3V3 will be
activated via the ENABLE-3V3 signal from the stand-by
microprocessor. If the +12V value is less than 10 V, the last
enumerated voltages will not show up due to the under-
voltage detection circuit 7105-1 + 6101 and surrounding
components. Furthermore, if the +12V is less than 8 V,
then also the +1V2 will not be available. The +5V5-TUN
generator 7202 (present only for the analogue version of
China platforms) will start to operate as soon as the 12V
(PSU) is present.
Codes, 5.5.4 Error Buffer, Extra