We have two Sharp Comfort Touch air conditioners, model AF-T606x, and one is much quieter than the other, the way the other is supposed to be. They were originally the same.
The bad one vibrates anything attached to the housing making a lot of noise, and the compressor can be heard nearly anywhere in the house when it's on. I have taken it apart several times to use foam to stop it from vibrating but the compressor is too loud. It's gotten to the point where I can't sleep with the stupid thing on now. Both are over 5 years old, should I see if I can get it repaired? What does the problem sound like it could be? I like the air conditioner, but it's become so loud.

First thing i would check just to be sure is the compressor mounts,sometimes springs and sometimes rubber grommets.Make sure it isnt vibrating against bottom of unit.Also are u pretty sure its the compressor?Have seen the fan blades seperate @ hub since it is just plastic and cause some vibration.Check all bolts and screws to make sure they are tight.Have u performed maintenance on this unit recently?Washing condenser coil and evaporator coil.Other than that it is hard to say because they dont make window units to work on when it comes to the refrigerant side,they dont even have line taps,although they can be installed but its not worth it.

Thanks for the reply. I believe this unit is actually over ten years old with a date stamp of 11-96 found on the fan. I have opened it up and the condensor was nearly completely clogged, and it was likely this way for a couple years, as I took it apart then to put foam in the areas that would vibrate and it was ok then. I never thought to check the condensor since I didn't think it would get dusty being outside, the evap I cleaned often removing the cover to clean the fins as well as the filter. I wonder if I burned out the compressor running it that way. I cleaned it and put it back together but it still sounds the same on the bench. It did seem to "smooth out" soon though, noisy at first and then quiet. I have yet to see if it's the same in a window, but I don't see why it would run any quieter now.. I'm thinking the damage is done already. Everything else checked out ok, no broken fan, shaft doesn't have play in it or anything. The compressor mounts are all there, but they look old since the rubber is cracked. I'm thinking I fried it..

Unfortunately,I think your right.Its pretty critical to take the unit out and wash the condenser and evaporator @ least once a year.If the coils get stopped up then you wont get the proper heat absorbtion/rejection needed to run properly.Then not only will it lose efficiency but proper evaporation may not occur causing liquid to make it back to the recip compressor and they dont like liquid.Probably damaged the valves.Ohh well,live and learn.Just remember that a proper maintenance program is the key to either a window unit or central air having a long and efficient life.

Thanks for your replies Baspro. I spent a good part of the day today working on both, cleaning them thorougly and adding foam insulation to parts that might vibrate. It actually seems quieter this time, but it was 60 degrees in the garage so it wasn't quite under load. We have several other window units and I plan on checking them all before removing them this year. It blows just as cold as it ever did though, so it still works just fine. I like these ones because you can specify the exact temp with the digital readout and not have to keep going back to a dial and adjusting it.
I am interested to know how the system works, what goes on inside the compressor? What makes the sound I hear on it?

Basically,u have a continuous cycle as far as the refrigerant goes.The compressor just keeps it circulating through the system.Works same as a car engine for the most part.The refrigerant condenses and evaporates @ different temps as opposed to say water.The refrigerant goes from the compressor as a hi temperature,hi pressure vapor.It goes through the condenser and condenses.The condenser basically removes most of the heat from the refrigerant.@ this point it makes its way to the evaporator in a liquid state because of the condensing that took place in the condenser(ready to absorb more heat).It goes through a metering device which cause the refrigerant to flash causing it to become a mixture of vapor and liquid.As it goes through the evaporator it absorbs the heat from the house and that heat is transferred into the refrigerant.During this process the refrigerant begins to evaporate.When it leaves the evaporator it should be completely a vapor.If say your evaporator is dirty,the proper evaporation cant take place and you could not have completely evaporated,causing liquid to make its way back to the compressor.A dirty filter could cause this also .A dirty condenser will basically cause u to lose efficiency and cause the unit not to cool as well because the refrigerant cant completely condense,which means all the heat wasnt rejected from the refrigerant.So when it makes its way back to the evaporator ,it cant absorb as much heat as it should be able to.There is a squirrel cage fan that intakes from the filter ,across the evaporator(refrigerant absorbs the heat),then the air is blown into the space.The propellar style blade blows across the condenser rejecting the heat to the outside.Then there are just sensors,switches dampers etc that start and stop the compressor,control fan speed,etc.Thats it in a nutshell.