MY POLAROID IDTV HDMI HAS SOUND BUT NO PICTURE?

Check its speaker. If it is found ok, check and replace the audio output IC. Check whether sound is muted or not.

OK try to check the sound board or sound IC

Well it very well could be the three color tubes, or power board the problem. BUT before you try that check your HDMI cable. HDMI cables have to be 100% in to fully work sometimes if out just a bit they will produce this issue where you have no picture but sound.
Or try a new HDMI cable, if you don't have HDMI and it's doing it on multiple ports including RCA, RF, HD Component then it's a problem with the tv itself and you'll need to call a repairman.

I am having a somewhat similar experience. The HDMI 2 is a little flaky on these TVs, try turning the input device that is attached to HDMI 1 OFF then reboot the TV. For some reason, if there is a signal going to both HDMI inputs at the same time there are major problems. I also found that if I input L/R audio into the HDMI 2 analog jacks, that sound also goes to HDMI 1(if no digital sound signal is going there).

make sure you have the correct video cable. if it uses HDMI, use highspeed HDMI cables. Same goes if you use display port and make sure the correct input source is selected on the tv.

You could try pressing the source button on the remote to see if that brings it up.

Also the TV may have got itself in a muddle. There will be a way to reset it to factory setting. If you can get into the TV's setup menu there ought to be an option buried somewhere to do that.

yellow is for video only, please use also the white and red rca plugs for sound, hdmi problem could be a to high resolution choose 720p or 1080i in de connected device.

COULD BE A BAD HDMI,,CHECK TO SEE IF ITS TURNED ON ON THE CABLE BOX

yeah stay away from polaroid! In the meantime check this out.

http://www.fixya.com/support/r741402-polaroid_flm_373b_lcd_tv_black_screen

Are you using HDMI? If so, the set may be misreading the signal as being DVI. Try running a stereo pair of audio cables to the RCA jacks associated with the HDMI input.