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Friday, January 31, 2014
Thursday, January 30, 2014
My first newsletter- members only
Beginning this month of January 2014, i will be publishing monthly newsletter.
This will be members only and therefore if you are interested on getting those updates, you are most welcome to join my mailing lists.
If you have already subscribed please don't do it again
See you on the other side
Humphrey Kimathi
Saturday, January 18, 2014
DVD player picture freezing and how to set the spindle motor height
Hi Humphrey,
One Samsung DVD player after 25min
of playing picture is freezing (stuck), sometimes picture is played
intermittently with broken sound. I saw optical block dancing backward and
forward when this trouble starts. Replaced spindle motor problem was same.
Thursday, January 16, 2014
Email support between me and a customer from Barbados
This is
Winston from Barbados, haven't spoken since March last year. Since then I have
acquired an analogue ESR meter, very easy to use, and it immediately showed up
faulty capacitors that I would not have found before.
I am
still focusing on CRT TV's though quite a few people are coming to me
requesting flat-screen TV repairs. I still have a very large CRT market
available here, and I want to repair ALL, except those where Tube is at fault.
Monday, January 6, 2014
LG Television hit by high voltage
This television belong to a
colleague, he informed me about his Television which he suspect was hit by
power surge because there was power blackout in his area and when power was
restored he switched on the television and was not working.
Usually equipment hit by power
surge is easy to fix and therefore I passed by his place in the evening after
work and upon opening the set I went straight to the safety components and I
started by testing the condition of the main fuse.
Testing across the fuse I got
a beep, I was not expecting that but in electronics we deal with facts and
therefore this is the truth.
Next I checked the health of
the surge limiter and again to my surprise it was also okay, with this I
concluded one thing....there is no shorted component on the supply.
So what is blocking the power
then? I started scanning the primary side components for any sigh of stressed
components.
Usually when component fail
due to power surge you can see marks on components body which have failed. So I
started scanning the primary side components and I noticed the main capacitor
rated 220uF/450V was swollen slightly at the top as you can on the picture
below...
Please note that there is no
point of re-testing a capacitor which is swollen because they usually short and
therefore if you test with an ESR meter it will read very low ohm, as you know
low ohm on capacitors using ESR meter means the capacitor is in excellent
condition but this is not the case because the low ohm here means the capacitor
is shorted...if you test using the capacitance meter you will also find the
capacitance is within range but this again is wrong result.
I continued scanning for
more culprits and now my attention was drawn by burnt marks on the inductor
which is part of the E.M.I circuit.
This component rarely fails
and I did a test for open using my meter and i found one line was open circuit.
This explain why the fuse and
the surge limiter was not open is because the component opened first and
therefore cut off the supply before doing more damage to the supply.
Getting this component (inductor)
for replacement was not easy and checking around my junk board I found any old
board of IBM CRT monitor which has a clean one and installed it on this TV.
The board after installing the
two components, please note that the new capacitor seems smaller than the
original one, this is because the new capacitor is rated 400Volts and the
previous one was rated 450 volts but the capacitance were the same 220uF.
I also installed the main
capacitor and after doing few test on other components and realised they were
okay went back to the owner and re-installed the board to the tube and after
applying power the TV was back to normal.
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