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Service Modes, Error Codes, and Fault Finding
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.
Q543.1E LA
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.
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.
EN 25
5.3 Step by step Start-
Codes,
5.5.4 Error
Buffer,
Extra
2009-Mar-27
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