[R-390] Case Comments -Long post

[Tim Shoppa]

Perry wrote:
> For the R390 the first solution to the regulator heat problem is to
install the SS regulator
> designed by Dr. Jerry in the HNS that has been mentioned before.  (I
can’t find it in my perusal
> of the index.  Someone please jump in.)  The next thing is fans.  The
cheapest bang-for-the-buck
> are 12 volt computer case fans.
> 
> The most common size that is sold by Newegg  is 120MM (about 4 ¾
inches.  For a little over $10 a
> pop you have a choice of CFM and noise levels.  They have customer
reviews that are very helpful.

My one comment about the $10 computer case fans, even the fancy-pants
ones, is that they
rarely last more than a couple of years. That's great for a computer
case - after all, the computer
is going to be obsolete before the fan goes bad - but the
industrial-duty fans and blowers
that cost a whole lot more than $10 are really and truly better than
anything I've ever found
in a computer shop.

That doesn't mean they'll outlast the radio. I fully expect that even
the best fans to die long
before the radio does.

My personal solution was a 240VAC 10-inch Rotrons that don't spin fast
at all at 120VAC.
Slowing it down was not done to push the life but instead to drop the
acoustic noise! In terms of life the fans had already had 15 to 20
years service in
industrial racks by the time I got to them.

> First the “A”. Because of it’s fold-over design it is more
important to get good airflow to the
> bottom than the top.  People have reported putting spacers under the
audio module because of the
> heat generated by the dropping resistors in the closed space.  Why no
one has suggested putting
> the resistors on top and the filter caps inside the audio module is a
mystery to me.

In fact others have. But I've never seen a 390A audio module with "bad"
dropping resistors or failed/
charred components around the dropping resistors. In my limited
experience it's a case of
"ain't broke - don't fix it".

Tim.