Stepwise Start-Up; Service Mode Of Converter Boards For Ambi Light; Service Mode Pads Ambilight Panel; Building Blocks Of Converter Board - Philips 42PF9731D Service Manual

• POD key validity. Indicates the key's validity, this will only
work with an authentic POD card.
• Digital Signal Quality. not applicable
How to Exit CSM
Press any key on the RC-transmitter (with exception of the
"CHANNEL +/-", "VOLUME", "MUTE" and digit (0-9) keys).
5.2.4

Service Mode of Converter Boards for Ambi Light

Purpose
To switch on the lamps manually in case I
fails.
The Service Mode can be activated by disconnecting
connectors 1M59 and 1M49 and then by shorting for a moment
the two solder pads [1] on the Ambi Light Inverter Panel. See
figure "Service Mode pads AmbiLight panel".
Figure 5-3 Service Mode pads AmbiLight panel
In this chassis, both single and double fitted boards can be
used. The double fitted boards are used in sets with 3 or 4
sided Ambi Light units whereas the single fitted boards are
used in sets with 2 sided Ambi Light units. A double fitted board
can drive 2 lamp units (6 lamps) and a single fitted board can
drive 1 lamp unit (3 lamps).
The double fitted boards are supplied by +12Va and +12Vb.
The microprocessor is supplied by +12Va.
Therefore, if only +12Va is available, lamp unit B will not work.
See figure "Building blocks of Converter Board" for details.
Inverters
+12Va +5V
Stab.
Board select
PWM out
I²C
Protection
Figure 5-4 Building blocks of Converter Board
Service Modes, Error Codes, and Fault Finding
2
C-bus triggering
1
G_15950_049.eps
060406
+12Va
Lamp unit A
Lamp unit B
+12Vb (12-13V)
G_15950_050.eps
The microprocessor performs the following tasks:
• Dimming of Ambi Light by means of PWM.
• Translation of I
• Switches the Ambi Light board to protection if needed (in
case of protection only the lamps switch off, no set
protection is triggered).
There are two ways of protection: parallel arcing protection and
serial arcing protection.
Parallel arcing protection is performed by sensing the switching
frequency. In case of short circuit of the transformer output, this
frequency > 100 kHz and the board goes into protection.
Serial arcing protection is performed by detection of arc in
ground wire of the lamp units. In this case, the protection pulse
is transmitted via an opto-coupler.
Protection can be disabled by short-circuiting diode 6112 or
capacitor 2173 or by connecting pin 8 of the microprocessor to
ground.
Repair Tips
In case only one or no lamp unit at all works, probably the
+12Vb (12 - 13 V) is not available or the fuse is broken. Check
for broken MOSFETS or check if they are switched off properly
by the transistors connected to the PWM outputs of the
microprocessor.
In case the Ambi Light switches off after two seconds, serial
arcing or parallel arcing protection is active. Serial arcing
protection can be excluded by disconnecting the opto-coupler;
check for bad solder joints on transformer or lamp units.
Parallel arcing protection can be disabled by grounding pin 8 of
the microprocessor. Usually the switching frequency (normally
63 kHz) will then be too high. Possible causes are one
MOSFET of the converter has no gate drive or is broken, or
there is a short-circuit of the output of the transformer.
5.3

Stepwise Start-up

The stepwise start-up method, as known from FTL/FTP sets is
not valid any more. The situation for this chassis is as follows:
when the TV is in a protection state detected via the Stand-by
Processor (and thus blinking an error) and SDM is activated via
shortcutting the pins on the SSB, the TV starts up until it
reaches the situation just before protection. So, this is a kind of
automatic stepwise start-up. In combination with the start-up
diagrams below, you can see which supplies are present at a
certain moment.
Important to know here is, that if e.g. the 3V3 detection fails
(and thus error 11 is blinking) and the TV is restarted via SDM,
the Stand-by Processor will enable the 3V3, but will not go to
protection now. The TV will stay in this situation until it is reset
(Mains/AC Power supply interrupted).
The abbreviations "SP" and "MP" in the figures stand for:
• SP: protection or error detected by the Stand-by
Processor.
• MP: protection or error detected by the VIPER Main
Processor.
060406
BJ2.4U/BJ2.5U LA
2
C-bus commands to PWM.
5. EN 19