[R-390] DIY cabinet/shielding questions

[Gene Beckwith]

Gents,

Interesting questions re cabinets for the R-390X's  ...  Several approaches
here...but some are;

1.  Use DX-100 cabinet per Hank posting...they show up from time to time, but
must do some custom hole cutting on rear panel if you use it...the depth
clearance is ok, but no room for errors...plus in my case the standard 19" hole
patterns were not what my DX-100 cabinets presented...drilled and tapped
them...not a big deal...but had to do it...

2.  Main station op position here at W8KXR is constructed floor to ceiling with
eight bays of racks that allow movable shelving...veticle shelving supports,
when needed are  'shimmed out' with addition of right angle aluminum stock to
fill gaps and provide for rack mounting...main weight is on shelving.  This is
an extremely flexible system and allows for lots of station changes as up
grading and mix an match combos are tried...Currently have two R390x's mounted
this way...vry neat . ..

3.  Open frame racks also used, but no R-390x should be mounted  suspended on
panel alone...this is old info discussed on this list several years ago...it is
also the way military racks were designed, in some cases, with essentially
'micrometer' shelf adjustments that came up under the rigs...to minimize panel
loading and main frame/gear train alignment.

4.  Bud has made custom runs of cabinets from time to time that are deep enough
for the R390x's and SP-600's . .. had to get 'em quick because they were sold
out within hours of posting...

5.  Have found cabinets at the Hamfests, that appeared to be for commercial test
gear wo mfg. id...but were deep enough to handle the '390's . .. gotta keep
looking and be a bit innovative in these cases...

6.  Have been able to scrounge (rescue) four computer cabinets from work that
were dumpster fodder...they are commercial grade, deep enough, mostly with five
to six feet of usable vertical mounting space....

7.  Also intercepted a two double 19" rack from scrapped scecurity system that
was being up graded...works great...easy to add support shelving either custom
fit per me, or scrounged shelving used for Video monitors in this case...

So, if you are persistent, these are some ideas...for avoiding a custom
build...really dressing up ur stuff, and avoiding valuable waste of time needed
for more building and scrounging...take your pick from really big for lots of
stuff, or one at a time stuff...

Good luck and good hunting...

Gene

W8KXR  - - - "Radio Free Warwick"


Barry Hauser wrote:

> Hi Adam & gang:
>
> First of all -- welcome aboard!
>
> When putting an R-390A in a cabinet or rack, an important consideration is
> ventilation.  You don't want to suffocate the radio.
>
> The basic mil procedure when installing in a cabinet or rack was to remove
> top and bottom covers, which is why so many are missing.  It pays to keep
> the Utah cover in place as there aren't many tubes under it and it helps
> keep dust out of the coils.
>
> Might be arguable, but the 390's are pretty well shielded while uncontained.
> Additional shielding is needed only in special situations.  Wood has
> insulating properties, so you have to make sure there are plenty of vents in
> whatever  you build.  The '390's have the "H-frame" design with modules
> suspended on the bottom.  The convection air flow is primarily from the
> bottom and out the side panel holes (for the "downstairs modules").  So, the
> case design should have openings on the bottom AND the sides, not just one
> or the other.
>
> Consider simply getting a nice top cover.  If Fair Radio won't break a set,
> check with Hank Arney.
>
> If you're going to make a full wooden cabinet, plan on cutting a lot of vent
> holes.  (Some kind of open frame design might be more practical.) Leave the
> top and bottom covers off.  If you add screening, I'd suggest a fine mesh so
> it helps keep some dust out, but not so fine that it restricts airflow.
>
> You might be able to find a standard cabinet at a reasonable price (under
> $100) that will fit -- or maybe one that's taller with room for
> "accessorizing".
>
> Barry
>
> Adam wrote:
> > Hello everyone. I recently began work on my R-390A and, since I don't have
> > any sort of cabinet or rack for the set to go in, I've been toying with
> the idea
> > of building a wooden cabinet for it. I thought that this sort of project
> > would be relatively straightforward, but then the issue of shielding came
> to mind.
> > Are the top and/or bottom covers detrimental to the correct operation of
> the
> > receiver? I have the bottom cover and the oft-mentioned "Utah plate," but
> am
> > currently missing the top cover (anyone know of a source for just this one
> > cover? Would Fair Radio be willing to sell me only the top one, since the
> bottom
> > one is passable?). While looking through the overheating section of the
> R-390A
> > Pearls of Wisdom archive, I found one post which said that the milspec
> metal
> > cabinet one owner had used RFI screening over all the holes in the case.
> Would
> > it be better to try to restore the top cover, cover the insides of the
> wooden
> > case with some sort of metal screening, both, or would neither be
> necessary?
> > Also, what would be the best way to bolt the R-390A into the wooden
> cabinet?
> > TIA.
> > -Adam
> >
> > Adam Vaughn
> > Collector of old computers, video game systems, radios and other
> electronic
> > equipment...
> > Visit my page at
> > http://www.angelfire.com/ma2/AdamVon/index.html
> >
> >
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