Introduction: Samsung LCD TV on Off Issue DIY Repair Fix
We had a Samsung 32" LCD TV go on the fritz recently. The television would turn on, then immediately turn itself off, then turn on again...in a never ending cycle. After doing a little research, we discovered that there had been a recall on these televisions due to faulty capacitors used during manufacture.
We also discovered the recall had ended a couple of years ago.
Not wanting to buy a new TV or pay an estimated $150 to have it repaired, I grabbed my trusty soldering iron and went to work. It turns out that for only $3-$6 in parts, you can fix this problem yourself. The only skills it takes are some basic soldering and desoldering techniques. Here are a couple of excellent Instructables written by other authors explaining these skills:
Now on to materials...
Step 1: Materials
Do do this repair (other than a faulty LCD tv), you will need*:
- Soldering Iron
- Desoldering Braid** or De-solder Vacuum Pump
- A replacement capacitor (more on this later)
- A Phillips Screwdriver
- Wire Clippers
- Helping Hand (optional)
*Links point to the specific item I used.
**Do yourself a favor and make sure to buy braid or wick with flux already in it.
Step 2: Disassembly and Diagnosis
In almost every case, this particular issue is caused by one or more capacitors on the power supply board over heating. Finding an overheated capacitor is simple once you get the back off the television. Take pictures as you go in case you need to refer back to where things are, particularly on the circuit board.
Carefully remove the stand and the back of the television. Be sure you have a clean, flat surface to lay the television on face down, then remove the stand followed by the black screws around the outside of the back of the television. If all the screws have been removed, the back should lift up and off very, very easily. Do not force it.
The power supply board is on the right. If you look at the picture of the power supply, you will see a closeup of an burnt out capacitor. Notice the top is no longer flat, but has puckered up and separated. To remove the power supply board, Carefully unplug the two cables running to the board (one on the left and one on the top). Then unscrew the silver screws at the four corners. There will be an extra screw in the bottom left corner of the board where the power cord plugs in. This is noted on the picture. Do yourself a favor and screw the silver screws back into their holes so that you don't lose the screws or where they go.
Now we desolder...
Step 3: Out With the Bad Part...
We mount the board in the helping hands, noting where the bad capacitor is located on the underside. We then desolder the connections, and remove the part. Did you remember to note which way the capacitor was mounted? Did you take a picture? The easy way to remember which way the capacitor goes is to remember which side the vertical stripe was on. If you need help desoldering, just consult the Instructable at the beginning of this one.
Now we solder in the new one...
Step 4: ...In With the Good Part.
Making sure we have the capacitor mounted the right way, we now solder in the new capacitor. How did we know which capacitor to buy?
There are three key features that identify a capacitor. First, it's capacitance, second, it's voltage, and third, it's leads. There may also be a temperature specification as well. For our capacitor, all we need to identify a proper replacement is the nominal capacitance in micro-Farads (47µF), the working voltage in volts (160v), and finally, since both leads come out of the bottom, this is a radial capacitor (as opposed to an axial or snap-in capacitor).
I found ten of these on Amazon for 15 bucks. That's $1.50 to repair the TV, as opposed to paying $150. I don't mind buying 9 extra capacitors, because someday I may find a use for them.
Now we put it all back together right?
Step 5: Test First, Then Reassemble.
Replace the power supply board in the TV (aren't you glad you didn't lose those screws?), plug the two cables back in, and then plug the TV in and verify it is now working. If it isn't, did you solder the capacitor in the right direction (+/-)? Is there more than one capacitor burnt out that you missed?
If you have verified that the television is working properly, replace the back and the stand and then enjoy the fruits (and savings) of your labor!