[R-390] Metal strips on inside of 390A's side panels?

[Barry]

I'd guess that bad welds combined with a couple of shock drops could have
popped the welds.  I would investigate getting them spot-welded.  JB Weld or
Super Glue (or even epoxy) really doesn't bond well enough to do the job
here (at least in my opinion).

Barry - N4BUQ

----- Original Message -----
From: "Tim Shoppa" <shoppa_r390a at trailing-edge.com>
To: <shoppa_r390a at trailing-edge.com>; <r-390 at mailman.qth.net>;
<N4BUQ at aol.com>
Sent: Monday, January 16, 2006 7:12 PM
Subject: Re: [R-390] Metal strips on inside of 390A's side panels?


> "Barry" <N4BUQ at aol.com> wrote:
> > Those strips are spot-welded, not glued, to the side panels.  It is a
clever
> > way to gain extra support for the main shelf.  The weight rests on these
> > instead of relying on the shear strength of those little #6-32 screws.
All
> > the screws do is keep the center shelf tight against the side panels
while
> > the spot-welded strips take the weight.  Also, it helps keep the center
> > panel at precisely the right height so that the controls will be
centered as
> > closely as possible.
> >
> > Barry - N4BUQ
>
> Thanks Barry. On my yellow striper the welds had undone themselves
> (what would undo spotwelds?) at a couple
> of welds. For now some super-glue seems to be holding them in place,
> although I'm dubious of super-glue providing enough strength to keep
> the main deck plate supported, that sounds like a job for JB Weld :-).
>
> Project for 2005: manufacture an entire R-390A entirely out of JB Weld!
>
> Maybe the strip is a different alloy than the aluminum side plate,
> and temperature differentials did the work of detaching them?
>
> And another chemical testimonial: Goof-off is good at removing spray
> paint from the back and side panels. Takes several applications followed
> by scraping but it does work (and the original legends are still at
> least mostly there.) It also removed dymo label remains nearly instantly.
>
> Also went into both my RF decks and replaced a bunch of out-of-tolerance
1/2W
> carbon comp resistors. Lots of 10K's were at 20K+, many 2.2K's at 6 or 7
K,
> a 1M at 2M, etc. The worst of them had signs of charring (past abuse?)
> I know I'm a heretic for it, but most of them got replaced by 1W metal
> films (yeah, yeah, tell me all about their self-inductance...)
>
> Why so many charred out-of-tolerance resistors on my RF decks? One
> was a Stewart-Warner yellow-striper, the other is a Stewart-Warner that
> has been very gingerly treated over the years. Incidentally, the serial
> numbers on my two RF decks: #625 and #626! Twin brothers, separated
> at birth, one treated royally, the other abandoned at SJC, and finally
> reunited on my bench!
>
> Tim.
>