Earth Info

My Samsung TV (52″ LCD) started clicking several times before finally switching on after 30 seconds, this relay clicking gradually got worse each time I turned the set on. ( It turns out that this is quite a common problem with Samsung TV’s of all sizes). The problem seems to start after the TV is a year or two old (normally outside guarantee) and sounds like a relay clicking on and off. Samsung deny there is a design problem, so I thought rather than spend money on an engineer, I would try and fix the problem myself.

I thought the first place to look for a problem like this is in the power supply.

• I unscrewed the back cover of the TV (20 screws)
• Removed the metal cover of the power supply (4 screws)

  

• I carefully looked over the power supply looking for anything out of the ordinary, low and behold I could see a few capacitors (the cylindrical shaped components) that had raised tops. These raised tops are caused when the capacitor breaks down and forms hydrogen gas, if left, eventually the capacitors will blow, and hopefully the top will split open and release the gas pressure, if not, they may just explode.

Check out Capacitor Lab for more details on what to look for when a capacitor fails.

I checked out the replacement cost of a new power supply board, I couldn’t find the exact power supply online but this company has ones for smallers TV starting at around £160. So I was guessing it would be around £200 for a new one. Ouch, definately time to DIY.

I decided to replace all the capacitors in the power supply, I guessed if some were bad, then probably Samsung use cheap or poorly designed capacitors and at some point the others would go bad too. and replacing all the capacitors wouldn’t cost much more .

Each Capacitor has 3 important values

1. The capacitance measured in μF (micro farads) eg (1000μF)
2. Voltage (eg 50V)
3. Temperature (eg 105°C)

This particular Power Supply Unit (PSU) has 3 different types.

• 1000μF 105°C  at 10V
• 1000μF 105°C  at 25V
• 47uF  105°C  at 50V

RS Components have a good selection,  so I opted to buy from there. It cost about £12 including postage for a 5 pack of each of the capacitors.  I took a few photos of the circuit board so I wouldn’t forget what I was doing and set to work.

I re-opened the TV, and completely removed the Power Supply Circuit Board, you need to remove several connectors, again, I took some photos just in case I couldn’t work out where they all went when putting it back together. I made sure the Power Supply didnt have any residual power stored in the capacitors by unplugging the TV (whilst it was turned on) from the plug. This is very important as messing with a power supply even 30 minutes after it has been turned off can still give you a nasty shock.

I then drew a simple diagram marking the polarity of each capacitor. To remove each capacitor takes a little time, you need to heat each pin using a soldering iron and whilst it is still molten pull or wiggle each leg out in turn. I found it easiest when I used the other leg as a pivot and rotate the capacitor around the fixed leg.
Anyway once removed, you I used the de-solder pump to clean up any solder that was clogging up the hole and then I inserted a new capacitor (checking the values again) and making sure the polarity was same as the one I had just removed. turning the board over, I bent the pins a little, soldered the joints, and snipped off any left over wire.

I put the board back in and hey-presto it all worked beautifully. Job took about 2 hours in total and excluding tools £12 for the components and postage.

[Added 21th May 2009]

If you snap off the solder connector on the PCB when doing this replacement, it is worth noting that you can re-attach your component in another place as long as it is electrically equal. The Red Line in the diagram below shows where an existing component was, this component could then be re-soldered into any of the positions marked in green. But in the case of a capacitor which has + positive and – negative legs, you must make sure that the leg is re-attached to the same track, I have marked with a + plus sign which track it must be re-attached too.

[Added 7th Dec 2009]]

After replacing the capacitors a few people are still having problems, it appears that this can be fixed by resetting the EPROM chip (apparently – a simple matter of shorting two of the pins).  http://www.tv.quuq.org/forum/index.php?topic=2377
and http://www.tv.quuq.org/forum/index.php?topic=1744.0 both detail the procedure, although it hasn’t worked for everyone who tried it. (Thanks to Jason for these links)

[Added 10th March 2010]

You are not alone, there have been almost 65,000 visits to this page in the last year. The answers to many of the questions people are asking are scattered through the previous comments, Most people with little experience have been successful in fixing their TV’s although for a few, it didn’t work, the symptoms were similar but cause was different. A few of the more recent comments reveal that people are becoming more successful with getting Samsung to repair their TV’s, its definitely worth trying before you launch into a self fix.