Friday, October 25, 2013

Faulty capacitors and the light bulb conspiracy !

I had read a while ago (in 2009) that the Samsung LA32A330 LCD TVs had a problem of faulty capacitors. The capacitors rated 2200uF,10V were delivering to a 12V or a 16V bus causing stress on themselves. This finally would lead to the capacitor's breakdown. Eventually this was felt by me when I tried to switch the TV on and it failed.

We had bought the Samsung LA32A330 TV in October 2008. The capacitor's breakdown was gradual. I say that as a fact since I felt it in the form of ever increasing TV start up time and the associated ticking sound at that time. Finally the time it took to switch on was = infinity. It was then I mustered up enough courage to open the TV's back and do the correction. Now that I had nothing to lose!

Some online searches (1)(2) reassured me that this was something I could do. All I had to do, as per this YouTube video by BigDog (3), was

- Unscrew the back cover
- Find the suspect Capacitor (swollen?)
- Unplug the 5 plugs and remove the screws
- Desolder the capacitor
- Replace it with a capacitor 2200 uF 16V
- TAKE CAUTION : Make sure the -ve lead goes towards -ve (shaded area)
- Resolder
- Put the screws and all plugs back

- DONE !

The last time that I did any soldering or dealing with circuit boards was quite a while ago in college. Soldering irons themselves have advanced a long way since then. I took the challenge since the potential rewards were worth the attempt. The capacitor that I had to buy cost only 0.0025% of the price of new TV or 0.01% of the cost of a Samsung technician's visit.
The board with the puffy capacitor
The board with the puffy capacitor
With a dash of help/inputs from colleagues who were adept at circuit boards and soldering, the new capacitor (2200uF and 16V now) found its place in the old circuit board.

It was done. Now I had to just put the board right back and taste success. And taste success I did .. the TV switched on (the powering up time for the TV had decreased to just 2 seconds) and I saw the picture from a local TV station playing out clearly on the screen. It was late, so I powered off the TV and headed to bed.

The following day, returning from work, I switched on the TV again and to my dismay I saw that after playing for 5-10 minutes the TV started to act up. There was a green tinge on the screen and the black parts of the picture frames were not showing up correctly.

On no ! My mind whirred with a lot of questions.  
  • Was the capacitor acting up ?   
  • Did I not solder the capacitor to the board correctly ?   
  • Did I damage any other component in the process of the correction ?   
  • This seems to be a more complicated issue. Will I be able to solve it ?
Gathering myself up from the disappointment, I proceeded to attempt to repair this new issue.

As usual, I did some Internet searches again with strings such as "Samsung LCD green screen" and so on. Most searches resulted in forums with topics such as 'The green screen of death' where sandro3342 mentions that lint in the TV at the connections causes these issues. And further the solution seemed to work for davidmparsons and masterstint. Considering that I might have kicked in some lint into the connections while repairing the board, I proceeded to clean the TV up. Well .. that did not solve anything and the green tinge remained.

At some point that evening, I gave up and thought I would sleep over the matter, clear my head and check the following day since it was a holiday.

The following morning, I tried to clean up a bit more and when that did not yield any results beyond the time I had set aside to attend to this matter, I gave up. The direction I was taking was only trial-and-error based and it was not yielding any results. So I switched to TV back on after putting all the connections back and was playing around with the TV settings. I manipulated the brightness/contrast and bit on the TV channels and lo! the picture was now perfect ! So that was all it needed a slight adjustment to the brightness/contrast adjustment ! 


I think it was my recent interaction with the TV system led me to believe in the fact that the problem was more complicated than it really was. Plus to add to the mystery the picture seemed to be OK when I had switched it on just after I fixed the new capacitor in.

I have no explanation for this. Maybe the power reset (disconnecting the power from the mains) in between had caused some of the components to reset to some default values due to the addition of a new component .... any theories/explanations ?

Switching lanes now ...

Internet searches reveal that this is a known problem (4), rampant and recurring again and again over and over again across all Samsung models, even as they advance.

Hence the thought : Is this in anyway connected to the lightbulb conspiracy (5) ?!

'The Light Bulb Conspiracy combines investigative research and rare archive footage to trace the untold story of Planned Obsolescence, from its beginnings in the 1920s with a secret cartel, set up expressly to limit the life span of light bulbs, to present-day stories involving cutting edge electronics (such as the iPod) and the growing spirit of resistance amongst ordinary consumers.'



Credits
Carlos for the advice/help with the soldering know-how
Donny for pointing me to the food for thought Light bulb conspiracy.

References


(1) A blog article of a non-electronics guy's experience with the TV repair
(2) A YouTube video of an upset Samsung customer
(3) A YouTube video demonstrating simply how the replacement of capcitors is to be done
(4) A plethora of YouTube videos showing different Samsung TV's with similar problems -
(5) The light bulb conspiracy
(6) The green screen of death forum topic on CNET

No comments:

Post a Comment