Service Modes, Error Codes, and Fault Finding
5.
Blank Screen
Figure 5-9 Fault finding tree “Blank screen”
5.8.4
Source Selection
Set is not able to go into AV or any missing AV is
encountered
E.g. AV1 is available but not able to enter to AV1: Check if the
option setting is correct.
Set is able to go to AV, but no audio is heard.
1.
Check that continuity of signal is there from the SCART/
Cinch input to the input of the Hercules.
2.
If continuity is there and still no audio, check that option
settings are correct.
3.
If logic setting is correct and still no audio, proceed to Audio
Decoder/Processor troubleshooting section.
Set is able to go into AV but no video is available:
1.
Check continuity from AV input to HERCULES depending
on the input.
2.
If continuity is available and yet no video, proceed to Video
Processor troubleshooting section.
5.8.5
Tuner and IF
No Picture
1.
Check that the Option settings are correct.
2.
If correct, check that supply voltages are there.
3.
If supply voltages are present, check whether picture is
present in AV.
4.
If picture is present in AV, check with the scope the Tuner
IF output signal by manual storage to a known channel.
5.
If IF output is present, Tuner is working fine. If no IF output,
I2C data lines may be open, check continuity of I2C lines.
If I2C lines are ok, Tuner may be defect, replaced Tuner.
6.
If Tuner IF is present and yet still no picture in RF mode, go
to Video Processing troubleshooting section.
No Picture, No Sound
Figure 5-10 Fault finding tree “No picture, no sound”
Blank Screen
Check Vg2
(fine tune)
Check Beam Current Limit
(voltage is 1.8V-2V when
brightness and contrast is
set to the maximum
Not Ok
Check heater voltage
(measure pin 9&10
at the CRT socket)
Check video supply
(2457) is approximately
180V
Ok
Ok
Check deflection
circuit
Not Ok
Ok
Picture
appears?
Picture
appears?
End
Ok
Picture not appearing
Ok
Not Ok
Picture not appearing
E_14480_061.eps
170204
Check AGC
Voltage, pin 1
of tuner
No Picture,
No Sound,
Raster Ok
AGC voltage
changes with
different signal
strength
Check AGC
circuit section
No
Check tuning
supply voltage,
pin 9 of tuner
Yes
E_14480_062.eps
170204
Check
V
T
Supply
Section
>30V & <35V
Check supply
voltage, pin 7 of
tuner
5V
Check Power
Supply
No
Check Tuner
pin 4 & 5
I2C Bus
Yes
Ok
Replace Tuner
Check other
functional area
No
Yes
No
Summary of Contents for L04LAA
Page 36: ...Service Modes Error Codes and Fault Finding EN 36 L04L AA 5 E_06532_012 eps 130204 ...
Page 58: ...58 L04L AA 7 Circuit Diagrams and PWB Layouts Layout Mono Carrier Part 1 Bottom Side Part 1 ...
Page 93: ...Spare Parts List EN 93 L04L AA 10 10 Spare Parts List Not applicable ...
Page 94: ...Revision List EN 94 L04L AA 11 11 Revision List First release ...