Service Modes, Error Codes, and Fault Finding
5.
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
C
S
M
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...)
5.8.3
Exit “Factory Mode”
When an “F” is displayed in the screen’s right corner, this
means the set is in “Factory” mode, and it normally
happens after a new SSB is mounted. To exit this mode, push
the “VOLUME minus” button on the TV’s local keyboard for 10
seconds (this disables the continuous mode).
Then push the “SOURCE” button on the TV’s local keyboard
for 10 seconds until the “F” disappears from the screen.
5.8.4
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 cord”, presuming that the stand-by microprocessor
is operational.
•
If the input voltage of DC-DC converters is around 12.7 V
(measured on decoupling capacitors 2107 and 2123 and
the enable signals are “low” (active), then the output
voltages should have their normal values. The +12V and
+5VPOD supplies start-up first (enabled by PODMODE
signal from the stand-by microprocessor). There is a
supplementary condition for 12V to start-up: if the +5V-
POD does not start up due to a local defect, then +12V will
not be available as well. The +5V-ON supply is enabled by
the ONMODE signal (coming also from the stand-by
microprocessor). The +1V2 supply starts up when the
+12V appears, then at least 100 ms later, the +3V3 will be
activated via the ENABLE-3V3 signal from the stand-by
microprocessor. If the +12V value is less than 10 V, the last
enumerated voltages will not show up due to the under-
voltage detection circuit 7105-1 + 6101 and surrounding
components. Furthermore, if the +12V is less than 8 V,
then also the +1V2 will not be available. The +5V5-TUN
generator 7202 (present only for the analogue version of
China platforms) will start to operate as soon as the 12V
(PSU) is present.
•
The consumption of controller IC 7103 is around 19 mA
(that means almost 200 mV drop voltage across resistor
3108).
•
The current capability of DC-DC converters is quite high
(short-circuit current is 7 to 10 A).
•
The DETECT1 signal (active “low”) is an internal protection
(error 18) of the DC-DC convertor and will occur if the
output voltage of any DC-DC convertor is out of limits (10%
of the normal value).
Fault Finding
•
S
ymptom:
+1V2 not present (even for a short while ~10
ms)
–
Check 12 V availability (resistor 3108, MOS-FETs
7101 and 7102), value of +12 V, and surrounding
components)
–
Check the voltage on pin 9 (1.5 V),
–
Check for +1V2 output voltage short-circuit to GND that
can generate pulsed over-currents 7...10 A through coil
5103.
–
Check the over-current detection circuit (2106 or 3131
interrupted).
•
S
ymptom:
+1V2 present for about 100ms, +3V3 not rising.
–
Check the ENABLE-3V3 signal (active “low”),
–
Check the voltage on pin 8 (1.5 V),
–
Check the under-voltage detection circuit (the voltage
on collector of transistor 7105-1 should be less than
0.8 V),
–
Check for output voltages short-circuits to GND (+3V3)
that can generate pulsed over currents 7...10 A
through coil 5101,
–
Check the over-current detection circuit (2105 or 3127
interrupted).
•
S
ymptom:
+1V2 OK, +3V3 present for about 100 ms.
Possible cause:
SUPPLY-FAULT line stays “low” even
though the +3V3 and +1V2 is available - the stand-by
microprocessor is detecting that and switching “off” all
supply voltages.
–
Check the drop voltage across resistor 3108 (they
could be too high, meaning a defective controller IC or
MOS-FETs),
–
Check if the boost voltage on pin 4 of controller IC 7103
is less than 14 V (should be 19 V),
–
Check if +1V2 or +3V3 are higher than their normal
values - that can be due to defective DC feedback of
the respective DC-DC convertor (ex. 3152, 3144).
•
S
ymptom:
+1V2 and +3V3 show a high level of ripple
voltage (audible noise can come from the filtering coils
5101, 5103).
Possible cause:
instability of the frequency
and/or duty cycle of a DC-DC converter or stabiliser.
–
Check the resistor 3164, capacitors 2102 and 2103,
input and output decoupling capacitors.
–
Check AC feedback circuits (2120, 2129, 3141, 3153,
2110, 2114 and 3135).
•
S
ymptom:
+1V2, +3V3 ok, no +5V5-TUN (analogue sets
only).
Possible cause:
the “+5V5-TUN GENERATOR”
circuit (7202 and surroundings components) is defective:
check transistor 7202 (it has to have gate voltage pulses of
about 10 V amplitude and drain voltage pulses of about 35
V amplitude) and surrounding components. A high
consumption (more than 6 mA) from +5V5-TUN voltage
can cause also +5V5-TUN voltage to be too low or zero.
Note:
when a pair of power MOSFETs (7101 or 7102)
becomes defective, the controller IC 7103 should be replaced
as well.
5.8.5
Fan self test (only for sets with LED backlight)
In case fans are present, a softest can be done by pushing the
red coloured button on the remote control while the TV set is in
CSM. Exit CSM and check the status of the fans in the error
buffer by entering SAM ( info button on the RC). In
case of failure (fully red screen) more detailed information is
available in the error buffer (error 41, 42, 43, 44).
