Philips 32PFL9603D/10 Service Manual page 30

EN 30 5. Q529.1E LA
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 "5.3 Stepwise Start-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 error 1 = 2 or in SDM, LAYER error 2 = 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 error
layer 1 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
doesn't recognizes the keyboard commands at this time.
5.8 Fault Finding and Repair Tips
Read also section "5.5 Error Codes, 5.5.4 Error Buffer, Extra
Info".
Caution: For the whole platform the speaker connections are
grounded on -12 V level. During service measurements with
earth grounded equipment like e.g. scope, great risk of using
the speaker terminal connections for earth ground is currently
present. One will short circuit the -12 V to earth ground in that
way and will causes damage of the supply/audio part!
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 Audio Amplifier
The Class D-IC 7D10 has a powerpad for cooling. When the IC
is replaced it must be ensured that the powerpad is very well
pushed to the PCB while the solder is still liquid. This is needed
to insure that the cooling is guaranteed, otherwise the Class D-
IC could break down in short time.
5.8.3 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...)
Service Modes, Error Codes, and Fault Finding
5.8.4 DC/DC Converter
Introduction
The onboard supply consists of 5 DC/DC converters and 7
linear stabilizers. The DC/DC converters have all +12V input
voltage and deliver:
1. +1V2-PNX8541 supply voltage, stabilized close to
PNX8541 chip.
2. +1V2-PNX5100 supply voltage, stabilized close to
PNX5100 chip.
3. +3V3 (overall 3.3 V for onboard IC's).
4. +5V for USB and Conditional Access Interface and +5V5-
TUN tuner stabilizer.
5. +33VTUN for analog only tuners (AP diversity).
The linear stabilizers are providing:
1. +1V supply voltage (out of +1V2-PNX8541), stabilized
close to ST7101 chip (MPEG4 diversity).
2. +1V8-PNX5100.
3. +1V8-PNX8541 (reserved because +1V8-PNX5100 used
also for DDR2 interface of PNX8541 via 5FB0).
4. +2V5 (MPEG4 diversity).
5. +1V2-STANDBY (out of +3V3-STANDBY).
6. +5V-TUN (out of +5V5-TUN).
7. +3V3-STANDBY (out of +12V, reserved).
+3V3-STANDY and +1V2-STANDBY are permanent voltages.
Supply voltages +1V2-PNX8541, +1V2-PNX5100 and +1V are
started immediately when +12V incoming voltage is available
(+12V is enabled by STANDBY signal, active low). Supply
voltages +3V3, 2V5, +1V8-PNX5100, +1V8-PNX8541, +5V
and +5V-TUN are switched-on directly by signal ENABLE-3V3
(active low) when +12V and previous mentioned voltages are
all available.
Debugging
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 standby microprocessor and the
external supply are operational. Take STANDBY signal high-
to-low transition as reference.
When +12V rises above 10V then +1V2-PNX8541, +1V2-
PNX5100 and +1V are started immediately. Then, after
ENABLE-3V3 goes low, all the other supply voltages should
rise within 10 ms. Boost voltages should be OK when +1V2-
PNX8541, +1V2-PNX5100 are available (FU07 and FU8A,
around 19V).
SUPPLY-FAULT signal should be high when all supply
voltages are started-up.
Tips
• Usually, when supply voltage is short-circuited to GND, the
corresponding DC/DC converter is making audible noise.
• The drop voltage across resistors 3U70 and 3U3T is
100 mV to 2000 mV.
• Defective (in short-circuit) power MOS-FET's lead usually
to their controller IC broken; if one or more high-side MOS-
FET's (7U05, 7U08, 7U0D-1 or 7U0H-1) is broken then the
platform can be heavily damaged if started in SDM-mode
(SUPPLY-FAULT signal is then ignored, while higher than
normal supplies will be generated).
• The +33VTUN generator circuit (7U0P + 7U0Q +
surrounding components) has low output current
capability. In case of too low or no output voltage check
transistor 7U0P (gate voltage pulses of about 10 V
amplitude and drain voltage pulses of about 35 V
amplitude) and the load (not more than 4.5 mA).
• High output ripple voltage of DC/DC converters can be
caused by defective (cracked or bad soldered) ceramic
capacitors in the feedback (DC or AC) input or output
filtering.