Do you get sound when you play a DVD or CD?
If not then the problem is in the HTS and is probably not worth the cost of repair.
If you do get sound then the HTS may not be connected to the TV for audio. Connect the TV optical audio output to the optical input on the HTS using a toslink cable, Check the TV manual on how to use the optical out since it might not be active by default.
The KLH receiver has no function in your system unless you want to use the radio. You would connect the tape record out of the KLH to an unused audio input on the HTS.