I brought this tv in romania and the sound does not work properly. only on dvd the sound is ok.

Connect the surround sound to cable box or use a optical wire

check the Sounds with Local TV channels.Is it still low?If it is still low sound circuit has to be repaired.if it is ok,sound switching circuit has to be repaired(TV to Video)

keep tuning the sound and pictures have different frequencies.
okay

Make sure that in menu section on your tv, that you choose channel settings then the right setting are selected such as cable, air or whatever you are using in your area for receiption.

If the TV programs come's up with sound, then is possible that the TV set could be problem free. then cheek the system frequency if it need to be adjust from NTCS, PAL, AUTO MESECAM and so on. Cheek the DVD and VCR if they are in one of the following system settings and adjust the TV set to the settings at which the DVD or VCR is set to. Then you can also cheek if the cable is properly inserted, that is audio to audio and video to video. Nevertheless, if you have properlly connected your cables and set the system frequency to match with each other, and still no sound, then the TV could have sound problem.

Possible courses of sound failure in TV are as follows:-
1 RF stage
2 sound Ics or transistors
3 broken speakers
4 a break down resistor which supplie positive voltage to the sound curcult

check for proper connectionor check for playing another dvd. as every things seem to be ok.