Check that you have the correct Audio Stream selected on playback by using the Audio Button on the remote. Lack of audio would indicate the wrong Audio Stream may be selected. I sometimes have this problem when I copy recorded files from my Panasonic to my PC then playback over my LAN using my Media Player. TV1 and 3 and maybe others have 3 audio streams. From memory they are labelled Italian, English, English. Happened to me a few days ago and stream 1 (default) had blank audio but stream 2 had 5.1 sound and I think stream 3 is PCM stereo. I think stream 1 also carries audio description when available. I have no idea why one should be labelled Italian for English Audio. Strange indeed. Can't guarantee the same for your T2200 but worth a try. It can be quite confusing if you aren't aware of multiple audio streams.
Thankyou Very Much