How to troubleshoot the tv with sound on and off?

Try tapping the TV. If the problem comes and goes as you tap. There may be a dry solder joint on the circuit board or a loose connection.
If the above happens then explain this to the an electronic technician or someone who has some knowledge in repairing TVs.
You can attempt in re-connecting wires in the system but it can be dangerous as there are high voltages which can cause electric shock even if the system is off.

All the best
Rjn

Sir this problem is commonly caused by bulging capacitor or loosed connection, if you remove the back cover be sure to unplug the unit. Bulging capacitor is producing a low and unfiltered DC supply, one of the sign is the clicking noise you hear came from the relay. Or try to tap the side of your tv and observe if the tv will react.

This a bad capacitor
this is the loosed or dry joint it is much better if you use a magnifying glass to determine the loosed or dry solder. Good day and best regards.

The problem of your tv is the vertical deflection. Try to tap the side of your tv and observe if it will go to normal size if react the problem is the vertical IC there is a loosed or cold solder in the pin. If you are familiar with the electronic parts you can fix this by resoldering the loosed or cold solder to the vertical section of your tv. But if you tap the side and does not react you should replace the vertical IC, or you can contact a service technician to do it for you good day and best regards. Note before doing some trouble shooting you should unplug the unit.

Loose connection sounds like in the cable connectors in the inverter or the panel ribbons.

lg 42 in lcd tv power button blinks nine times before staying on and has sound but no picture

The "shadow" indicates a failure either of the LCD controller, LCD connector, or in the worst case, the LCD itself. A loose connection between the LCD and the LCD controller can result in abnormal displays. Try tapping the back of the TV and check if the shadow can be affected. If it is affected, try cleaning the connector terminals with a soft-bristle brush and alcohol or lacquer thinner. If not, have it checked by a qualified technician to carry out the proper tests to determine which of the LCD controller or LCD the problem lies.

no. possible loose solder connection but i believe it is sediment in neck of picture tube(crt) try while tv is on with the back off, tap tap tap the neck of crt with plastic side of screwdriver. hit it hard but dont break it. this will knock loose the sediments in the crt. fixed!

shannonlamb- check the back of your set where the cable ect. hook up, there may be a button on the back for speaker on/off.If not then check the menu to see if there is speaker on/off in menu make sure it is on.The last is the old tap test, just tap the back and sides,if you get sound at all it is internal cold solder joints.Let me know ----- cooltek Feb.15/08

Hi, A suggestion to a similar post @ http://www.fixya.com/support/t187720-no_sound If all else fails, you may want to try the "thump test" this will help you determine if its a loose/cold solder problem inside the TV. Give your TV a good whack at the side, top or back, if sounds comes on even briefly, it's a loose/cold solder problem, if not then you probably have to have the unit serviced by a qualified professional. The "thump test" is not a recommended action. Most techs would not even mention it but somehow it is performed (whether deliberately or not) by most. If verified that sound is faulty due to loose or cold solder, then it is a simple matter of locating the fault and resolder. Hope this be of some help/idea. Post back how things are or should you need further information. Good luck and kind regards.

a tap on the side tells me that it's a solder connection broken loose, most likely in the horizontal section. if you have experience with electronic soldering, you can fix it, otherwise take it to somebody that can fix it. thermal expansion and contraction(from turning the set on and off) eventually produces metal fatigue in solder connections, and the connection breaks loose, just enough that it sometimes works, and sometimes doesn't.