You have the OEM home theater. Same as the OEM in our rig. Quit working soon after PO gave us the keys. We fiddled with it a while then bought a Sony DAV-TZ140
Gave the un-needed speakers to some kid at church. He seemed happy. Unit is now about 8 years old, working fine. As Morich alludes, electronical devices are just not conducive to us old shade trees fixing them.
Whatever model you get, just make sure its a 5.1 to give you your surround sound and the "audio in" is compatible with the "audio out" on your TV (i.e., HDMI or RCA).
Side note: We are with your PO regarding TV and surround sound. Drives us crazy. Like it with music, though.
Fair Winds and Following Seas