My ht-z310 theatre (not speakers) seems to make a low buzzing noise when on. I dont know if its the fan, but i never noticed it in 2 years before. Also when powered off the unit (not speakers) makes a looping noise that id expect to hear if a dvd was spinning, along with a low whistle noise. This doesnt go away until i unplug the device

SOURCE: samsung ht-z310 home cinema no sound rear speakers

I seen the same thing when I first opened mine except my "center" speaker wan't working. It had to do with the "Mode" it was in. The Mode button at the botoom of the remote changes the speaker configuration.

There is also an option in the setup that allows you to turn on/off speakers for the system, all of mine were either Present or Small which enables them to work.

SOURCE: Samsung HT-TX72 Making noise after 2 months

The problem is the fan in the back of the receiver. A number of people have had this same problem. Somehow the fan rubs on itself when it is at the wrong angle. This also happens if the bearings give out.

You can very easily remove the top of the receiver. There's 2 screws on the sides and 4 on the back. The fan is held in by 2 screws. It is a 50mm 12V fan that you can probably get shipped to you for under $10. I have found some online for just a dollar. Type 50mm fan into google and buy one that is 12V (0.14A).

Or you can do what I did and battle with customer service for hours and hours. You most likely will have to pay the $25 to ship it to be serviced or you will be transferred to their parts retailer who tries to sell you one for $45. Eventually, if you are persistent, you might ask for the surpervisor's supervisor and with a steady tone manage to get the Samsung Service number (888.685.1349) where the friendly service agent will recognize your struggle and justly send you a fan for free or next to nothing.

Good luck!

SOURCE: Samsung HT-Z310 tries to load disc, but never does

I've had a similar problem where the disc continues spinning in the "loading" mode and then finally goes to "disc error." So, I opened the cover of the player, and noticed that the disc was not spinning as fast as I expected, and there was an extra unpleasant sound when the disc was spinning. Thus, I suspected there was an issue in the drive motor system: either the motor drive board, the motor itself, or the contact to the disc. I saw that there was dust accumulated on the rubber contacts to the disc, so I cleaned them with a q-tip. I then resetted the system, and the disc was the spinning normally again, and everything worked like before! (Other things I have tried in the past were cleaning the lens and updating the firmware, none of which worked) I hope this helps!

SOURCE: SAMSUNG HOME THEATRE HT-Z310 will not play dvd's

if its less than 1 year old get it fixed by samsung. if older, buy a new dvd drive http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=390140887510

SOURCE: Digital In on Samsung HT-Z310 no sound

Optical into your XBOX 360? If there is a connector that you are using to convert it, I was start by replacing that.