OK, this is what I found out using the SE_Navcore.9.205.547817_32mb navcore on my XXL 550 device.
After I tried both clean and overwrites of the navcore many of times I noticed that the any sounds don't function at all both in the media player and the LoquendoTTS "computer voices" also in the Voices "recorded sounds". I installed the VocalizerTTS_English__US__Samantha "computer voice" into the root of the TT drive under VocalizerTTS, after the reboot I can hear the speaker from the TT activate by the clicking sound it makes, the VocalizerTTS_English__US__Samantha "computer voice" I choose and run the sound test and it works.
So to recap the only sound that works is the VocalizerTTS_English__US__Samantha "computer voice" no other seems to work but for the occasional "recored voice" from time to time. The media player does not work ever.
Any useful help on finding a fix for all the sound issues is welcome.
Thanks.