Philips BJ2.4U Service Manual page 18

EN 18 5. BJ2.4U/BJ2.5U PA
• 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.
+12Va +5V
Stab.
Board select
I²C
Protection
Figure 5-4 Building blocks of Converter Board
The microprocessor performs the following tasks:
• Dimming of Ambi Light by means of PWM.
2
• Translation of I C-bus commands to PWM.
Service Modes, Error Codes, and Fault Finding
2
C-bus triggering
1
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Inverters +12Va
Lamp unit A
PWM out
Lamp unit B
+12Vb (12-13V)
• 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.
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