[R-390] Case Comments -Long post

[Mac McCullough]

So ANYONE or ALL who 'joined ' the Air Force were avoiding the ARMY...

you remain the larges jerk i know in recent times ...
I remember why it is i stay away or un-joined fortunatly you dont know and 
are ill informed and can back up very little if any of what you expouse ...

mac mccullough  w5mc ...



----- Original Message ----- 
From: "Perry Sandeen" <sandeenpa at yahoo.com>
To: <r-390 at mailman.qth.net>
Sent: Tuesday, April 08, 2008 11:10 PM
Subject: [R-390] Case Comments -Long post


> Gentlemen,
>
> There is no such thing as a louvered or un-louvered case that can properly 
> cool a R390, R390/A or
> SP600 without fans unless you're outdoors at the north or south pole.
>
> There are several problems unique to case mounting.
>
> 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.
>
> I don't have any experiences with the R390 but the following comments are 
> relevant to the "A" and
> most SP 600's.
>
> 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.
>
> On most of the SP 600's I have there are two 20W dropping resistors 
> underneath the power
> transformer.  A SP 600 may need to have all IIRC  three power resistors 
> remounted to the top side
> in order to have reasonable temperatures underneath.
>
> One needs to channel a lot of air under the case bottoms of each.  The "A" 
> is easier to cool
> because of the larger holes in the side as well as an empty interior 
> space where a small fan may
> be installed. So each will require different sizes of air ducting from 
> fans.
>
> We must remember that the receivers first had to meet a volume and front 
> panel specification.
> Then they had to meet performance specifications and a reparability 
> requirement.  With the "A"
> especially, module swapping could be done fairly rapidly by not very 
> skilled techs.  Receivers
> could be turned around faster.  If  module swapping or techs that joined 
> the AF to avoid the army
> in Viet Nam and weren't good at troubleshooting didn't fix at Karmursel AS 
> (A huge intercept base
> near Istanbul), they trashed them out.
>
> There was never, ever any specification for receivers to last 25 years or 
> longer.
>
> Regards,
>
> Perrier
>
>
>
> 
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