[Hallicrafters] SX-28A Restoration Question

[Barry H]

Hi Mark

Here are some alternatives to the solutions offered.

Offhand, I agree that you may be asking for trouble if you try to replace the sockets. You could leave them that way and put something on the brackets to retard further rusting.  Regular DeOxit may be good enough and fairly safe.  You could just manually scrape away most of the loose rust with a jeweler's screwdriver or whatever before applying it.

However, the one risk in leaving them that way is that they may be weakened to the point where they will break loose when you go to remove and replace a tube.

As an alternative to the chemical de-rusting approach suggested, you might try scraping and burnishing the accessible surfaces of the mounting rings as much as possible, then reinforcing them in place.  I would try "plating" them with solder.  Use a high wattage soldering gun (like 240 watts)  You won't be able to reach all parts of the clamps, so quite a bit of heat is necessary so as to sweat-solder/tin them.  It might also require some soldering paste.  I don't know if the degree of heat-sinking to the chassis will allow this -- but worth a try.

An alternative is, cleaning as much as possible -- also try a Dremel with a small cone-shaped wire brush bit. Do not use any oil-based product.  Then coat them with epoxy as neatly as you can.  Don't use that 90 second setup stuff.  You want something with an intermediate setup time so it will settle/puddle and make a smooth, even "plastic" coating.  The gray JB Weld Industrial might be a good choice.  It would be OK if some flowed and bridged the clamp and a bit of the chassis.  This would back up and support the weakened ring clamp as well as provide a rust proof coating. 

As the epoxy sets up, you can trim, clean up a bit.  After it is fully cured -- I'd allow several days or more -- you could apply some DeOxit D-5 from the top of the chassis around the tube socket itself so that it will (mostly)soak through and get to some of the inaccessible surfaces.

If you want to try the replacement approach - here's thought -- never tried it myself.  Find new sockets with the same mounting ring -- I would not harvest them from the parts unit if I could avoid it.  Use a Dremel to grind off the rivet heads on the old one, back it off and clip one side and bend it to liberate it from the wiring - don't unsolder the connections.  Pry the the ring clamp off the new tube socket and also clip it on one of the thin sides.  Bend so you can fit around the wiring and then flatten it out in place.  To hold properly, you may need to solder where you cut it.  Then push down in place and fasten with screws and nuts.  It may be when you remove the old ring there's enough of it to clean up and tin with solder and re-install.  Just a thought -- might be a bear.

First thing to do I think is take a small screwdriver or some kind of sharp tool and scrape off that surface rust.  Maybe it's not so bad and you can just clean up in place.  If what's left looks sturdy enough, then just coat them with some clear acrylic or something to prevent re-rusting.  That would be the best thing.  You would avoid use of any oily stuff if doing that so the coating will take. You could then do the DeOxit from the top, let it soak and then check to make sure it didn't flow through and lift the coating -- or just skip that step.

General guideline - less is more, and the physician's credo "Do no harm."

hope this helps
Barry









Hi Gang --

Working on my SX-28A and have found that most of the tube sockets have
rust on the metal securing them to the chassis (fortunately NOT the
ones in the RF compartment!).

http://www.qsl.net/k3msb/temp/SX28A2.JPG

Since several of them have ground lugs between the metal and the
chassis, I'm wondering if I should drill out the rivits and replace
the sockets (I have a junker SX-28A available...).

I'm wondering if I'm making more trouble for myself than it's worth by
replacing the sockets.   I've even half convinced myself that by
removing the sockets, I'll have more room to do the cap replacements. 
Dunno.   The radio does work now, but I'm worried about intermittants
in the future.   I could also just run a ground wire from each
effected socket lug to a new ground too.

Comments?

Thanks

Mark K3MSB
______________________________________________________________
Hallicrafters mailing list
Home: http://mailman.qth.net/mailman/listinfo/hallicrafters
Help: http://mailman.qth.net/mmfaq.html
Post: mailto:Hallicrafters at mailman.qth.net
----
List Administrator: Duane Fischer, W8DBF **for assistance**
dfischer at usol.com
----
Hallicrafters Collectors International: http://www.w9wze.org