Who am I?
I am an electronics beginner, I have done simple repairs before. I have a simple multimeter, a JYETech DSO-SHELL DSO150 and a simple soldering station. I do not have any replacement components in stock and I will have to order them if needed.
Samsung LE40F71BX / XEC
Description of problem
The TV freezes / switches off. The image freezes, then it distorts very briefly, then you get to see a snow image and then the TV switches off. All this happens within 3-5 seconds. After the TV has switched itself off, it starts up again and works as if nothing has happened. The problem is rare, I was unable to generate the problem myself. Because it is so short, I have not been able to film it either.
What have I done so far
Various sources on the internet recommend replacing the 1000uF capacitors on the power circuit board when Samsung TVs of this age have malfunctions. I have replaced both the 25V and the 10V 1000uF capacitors, but that has had no effect.
The problem of my TV is not mentioned in the service manual. I have measured the voltages mentioned in step “4-2-1 No Power” of the service manual:
C1034 - 3.310V
C1032 - 4.860V
IC109 (voltage regulator 3.3V) - 3.310V
Q113 (KSC1623-Y transistor) - 5,973V collector, 4,860V emitter, 5,498V base
C1024 - 5,498V
C1102 - 3.301V
C1140 - 1,743V
IC100 (voltage regulator 5V) - 5.020V
IC114 (voltage regulator 3.3V) - 3.308V
IC106 (voltage regulator 2.5V) - 2.490V
IC107 - I don't know what kind of component this is (AP1530 0628A)
IC108 - I don't know what kind of component this is (M6RF 010)
IC118 (voltage regulator 1.8V) - 1,806V
A5V - 5,973V
B5V - 5,505V
I get the impression that in step 4-2-1 it says that on C1032 I should measure 5V but I measure 4.860V there. I don't know if that is a correct value. However, I also do not know whether this has anything to do with the TV freezing / switching off. I would like advice on what I can try further. I don't know what the best next step is. Any suggestions?