Service Modes, Error Codes and Fault Finding
GB 26
L01.1A
5.
5.7
Protections
If a fault situation is detected an error code will be generated
and if necessary, the set will be put in the protection mode.
Blinking of the red LED at a frequency of 3 Hz indicates the
protection mode. In some error cases, the microprocessor
does not put the set in the protection mode. The error codes
of the error buffer can be read via the service menu (SAM),
the blinking LED procedure or via ComPair. The DST
diagnose functionality will force the set into the Service-
standby, which is similar to the usual standby mode, however
the microprocessor has to remain in normal operation
completely.
To get a quick diagnosis the chassis has three service modes
implemented:
•
The Customer Service Mode (CSM).
•
The Service Default Mode (SDM). Start-up of the set in a
predefined way.
•
The Service Alignment Mode (SAM). Adjustment of the
set via a menu and with the help of test patterns.
See for a detailed description Chapter 9 paragraphs
Deflection and Power Supply.
5.8
Repair Tips
Below some failure symptoms are given, followed by a repair
tip.
•
Set is dead and makes hiccuping sound
‘MainSupply’
is available. Hiccuping stops when de-soldering L5561,
meaning that problem is in the ‘MainSupply’ line. No
output voltages at LOT, no horizontal deflection. Reason:
line transistor TS7460 is defective.
•
Set is dead, and makes no sound
Check power supply
IC7520. Result: voltage at pins 1, 3, 4, 5 and 6 are about
180 V and pin 8 is 0 V. The reason why the voltage on
these pins is so high is because the output driver (pin 6)
has an open load. That is why MOSFET TS7521 is not
able to switch. Reason: feedback resistor 3523 is
defective.
Caution:
be careful measuring on the gate of TS7521;
circuitry is very high ohmic and can easily be damaged!
(first connect measuring equipment to ground, then to
the gate).
•
Set is in hiccup mode and shuts down after 8 s.
Blinking LED (set in SDM mode) indicates error 5. As it
is unlikely that
m
P ‘POR’ and ‘+8V protection’ happen at
the same time, measure the ‘+8V’. If this voltage is
missing, check transistor TS7480.
•
Set is non-stop in hiccup mode
Set is in over current
mode; check the secondary sensing (opto coupler 7515)
and the ‘MainSupply’ voltage. Signal ‘Stdby_con’ must
be logic low under normal operation conditions and goes
to high (3.3 V) under standby and fault conditions.
•
Set turns on, but without picture and sound
The
screen shows snow, but OSD and other menus are okay.
Blinking LED procedure indicates error 11, so problem is
expected in the tuner (pos. 1000). Check presence of
supply voltages. As ‘5V’ at pin 5 and 7 are okay,
‘VT_supply’ at pin 9 is missing. Conclusion: resistor 3460
is defective.
•
Set turns on, but with a half screen at the bottom.
Sound is okay
Blinking LED (set in SDM mode)
indicates error 3. Check ‘13V’ and ‘+50V’. If they
are okay, problem is expected in the vertical amplifier
IC7471. Measure with a scope the waveform on pin 17 of
the UOC. Measure also at pin 1 of IC7471. If here the
signal is missing, a defective resistor R3244 causes the
problem.
Summary of Contents for L01.1A
Page 48: ...Spare Parts List GB 88 L01 1A 10 ...
Page 78: ...56 L01 1A 7 Schematics and PWB s Layout PIP Panel Top View CL 16532010_010 eps 210301 ...
Page 79: ...Schematics and PWB s 57 L01 1A 7 Layout PIP Panel Bottom View CL 16532010_011 eps 210301 ...
Page 88: ...66 L01 1A 7 Schematics and PWB s Personal Notes Personal Notes ...