Philips BJ2.4U Service Manual page 37

5.6.2 How to Activate
Use one of the following methods:
• Activate the SDM. The blinking front LED will show the
entire contents of the error buffer (this works in "normal
operation" mode).
• 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 VIPER controller as detection device.
Since in these cases, checking of observers, polling of ADCs,
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,
+8V6, +1.2V, +2.5V and +3.3V.
• Protections related to breakdown of the safety check
mechanism. E.g. since a lot of protection detections are
done by means of the VIPER, failing of the VIPER
communication will have to initiate a protection mode since
safety cannot be guaranteed anymore.
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.
Protections during Start-up
During TV start-up, some voltages and IC observers are
actively monitored to be able to optimize 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 paragraph "Stepwise Start-up").
5.7.2 Hardware Protections
There are no real hardware protections in this chassis.
Although, in case of an audio problem, the audio protection
circuit will switch "off" the main supply. The stand-by
microprocessor will interpret this as a mains dip and will try to
start-up again.
In case of a TV with SDI display this will probably lead to
protection error 7 (8V6 error) and an internal error 11 (so it
looks like an overvoltage protection of the SDI supply itself).
In other cases it will lead to error 14 (audio protection).
Repair Tips
• It is also possible that you have 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).
Service Modes, Error Codes, and Fault Finding BJ2.4U/BJ2.5U PA
5.8 Fault Finding and Repair Tips
Read also paragraph "Error Codes" - "Extra Info".
5.8.1 Exit "Factory Mode"
When an "F" is displayed in the screen's right corner, this
means that the set is in "Factory" mode, and it normally
happens after a new SSB has been mounted.
To exit this mode, push the "VOLUME minus" button on the
TV's keyboard control for 5 seconds and restart the set
5.8.2 MPIF
Important things to make the MPIF work:
• Supply.
• Clock signal from the AVIP.
2
• I C from the VIPER.
5.8.3 AVIP
Important things to make the AVIP work:
• Supplies.
• Clock signal from the VIPER.
2
• I C from the VIPER (error 29 and 31).
5.8.4 PACIFIC 3
In case the Pacific fails, the TV will go to stand-by. The reason
for this is, when there is an occasional boot problem of the
Pacific, it will look like the TV has started up in stand-by mode,
and the customer can switch it "on" again. When there is an
actual problem with or around the Pacific the TV will go to
stand-by every time you try to start up. So this behavior is an
indication of a Pacific problem.
5.8.5 Ambilight
Note: in case of Ambilight protection, the TV itself will not go to
protection, only the Ambilight board. When you disconnect the
TV from the mains and reconnect again, the Ambilights will
work again.
In case of multiple protections, check and replace the inverter
transformers and/or the lamp unit(s).
Protections on the ambilight boards:
Parallel arcing protection.In normal operation the inverter
frequency is ±63 kHz. In case of short circuit of the transformer
output the frequency is >100 kHz. Protection is done via
sensing the switching frequency.
Serial arcing protection. The detection of the arcing is done
in the ground wire of lamp units. The µProcessor is counting the
protection pulses. When 50 pulses are counted within 2
seconds, protection will be triggered.
5.8.6 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/AC Power cord, presuming that the Stand-by
Processor is operational.
• If the input voltage of the DC/DC converters is around 12 V
(measured on the decoupling capacitors 2U17/2U25/
2U45) and the ENABLE signals are "low" (active), then the
output voltages should have their normal values.
• First, the Stand-by Processor activates the +1V2 supply
(via ENABLE-1V2).
5. EN 37