Sound on 2 channels a problem

Question

I have owned a 32 inch Digimate 32 inch LCD television for several years, with no problems until recently.
I live in BC, and am serviced by Shaw Cable, Nanaimo.
About a month ago sound on channel 23, CBC News channel, became two - the sound for channel 23 plus a second source, a ? radio station. This week a second problem has surfaced, now in addition to the problem on CBC News, there is no sound at all on the HISTORY channel, channel 38. Both of these channels are nomal on other TVs in the same house.