Z5101 AIO - Noisy, Warm - Fan Replacement??

Hi there,

My neighbour gave me a Z5101. I see why...the noise must have been driving him nuts. The fan on the heat sync runs continuous and usually quite fast (sometimes very fast). I'm not sure if the speed of the fan is really dynamically controlled, or only somewhat. I also think the fan may not be made of steel bearings /rollers, which may be contributing to the high noise level, as well as possibly a dearth of lubricating oil. I would like to replace it...does anyone know the exact size, and knows of a reputable fan supplier where a quality fan could be purchased to assist in lowering the noise level?

A second question is: *IF* the internal fan speed can be slowed somewhat by a controller, is it worthwhile to put a largish, low rpm fan in the case so that the heat sync fan doesn't run so fast? Given that I got this AIO for free, I'd like to salvage it. ...or at least be able to listen to music.