I have a Sony STR-DA5200ES amplifier hooked into a sound system and a 52" Samsung LCD TV. The system is set up to operate on HDMI. The problem that has started recently is that the amplifier polls between HDMI and other functions/channels. When it polls, the sound goes away. I have activated the small button labeled HDMI on the unit, but this does not change the problem. What could be causing the unit to poll between functions.

Hello,
Normal 0 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} Is the cable connection hdmi? is the unit capable of upconversion to hdmi, if you use a component connection? probably not. if it is capable of upconversion, check your input menu settings.
or

Normal 0 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} The HDMI on the Sony STR-DA5200ES does not pass the audio. You need to either connect an optical or digital cable from your audio source. If it is a cable box or DVD player there should be audio outputs in addition to HDM.
Hope this will help...