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I know that many Sony owners are bothered by the fan noise of the HD-100. I have the Panasonic TU-HDS20 and it also has some fan noise issues, although not as bad (according to some) as the Sony.

I spent most of today working to quiet my fan. I started with a suggestion posted by Ricka in this thread http://www.avsforum.com/ubb/Forum11/HTML/013494.html. Ricka added nylon washers and nylon nuts to the fan mounting screws and felt he reduced noise by 20 to 30 percent. I did this and found that the noise reduced very slightly.

Removing the fan from the unit (but leaving it plugged in) taught me that the fan itself is virtually silent. So the problem is not fan mechanical noise.

Next, I thought that the noise was caused by air flowing across the metal cutout in the back of the chassis frame. So I went ahead and cut out that section of the chassis, leaving a round hole the size of the fan. (I sure hope I don't need warranty service!! http://www.avsforum.com/ubb/biggrin.gif ). That also quieted the noise ever so slightly, but still not very much.

Next, I experimented with trying to isolate the fan in case the noise was caused by vibrations from contact with the frame. I used some high density foam, about 1/4" thick. I cut remounted the fan with this foam between the fan and the frame, and used rubber washers at all contact points to try to isolate the fan. This also reduced the noise slightly.

At this point I was pretty happy, as these things together had done a pretty good job of making a noticeable reduction. Using my sound meter, I realized that I had reduced the noise level by about 10DB, to the point that I couldn't really record it on my meter.

Then I put the cover back on, and things got noisy again!! http://www.avsforum.com/ubb/mad.gif After another hour or two of testing, measuring and trying everything from isolating the cover with foam, to using a home made "deflector" to change the airflow path, nothing really helped. My sound meter doesn't indicate that the noise is signficantly louder, but the pitch is certainly different, which makes it seem to be quite a bit louder.

Long story short, at this point it appears that the noise is caused primarily by the airflow characteristics or some sort of harmonic amplification caused when the cover is on. There doesn't appear to be a good fix, other than leaving the top off, or unplugging the fan. Both of which I considered.

Yes, my fan is a bit quieter, but still "hearable" from 10 feet away if nothing else is running.

I took a bunch of pictures of my experiments and will try to post them to my web site in a day or two. Unfortunately, my digital camera is on the fritz, so I had to use my regular camera. I'll need a couple of days to get the film developed and the pics scanned. I'll post when the info is on my site.

Hope this helps others. Wish I had found a great fix, but I can't honestly say that I did.



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[This message has been edited by Steve13 (edited 04-24-2001).]
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