[Hammarlund] Cleaning Old Radios, second steps

[Bill Kirkland]

Don't forget the number #10 stainless as well.  A reasonable stock of screws 
set me
back about $200 at Spaenaur. McMaster Carr refused to ship to Canada.

Once I get started on those brass gears, I can't stop. Too bad it all gets 
hidden by the front panel.

The one I am working on now is going to be a real challenge. Some of the 
screws are rusted in solid- both on the side panel and on the coil cans.

Bill, ve3jhu
http://www3.sympatico.ca/kirklandb/
http://www3.sympatico.ca/kirklandb/sp600/SP600%20Restorations%20and%20Information.html


>From: "Tisha Hayes" <tisha.hayes at gmail.com>
>To: hammarlund at mailman.qth.net
>Subject: [Hammarlund] Cleaning Old Radios, second steps
>Date: Wed, 10 Dec 2008 09:27:32 -0600
>
>What I have found that takes a radio to the next step after the scrubbing
>and cursing is to replace all of the screws, washers, nuts and bolts with
>stainless hardware. This is a good opportunity to re-cinch all of the
>hardware and do spot-cleaning on places you would never see. It is amazing
>how organized everything looks when you get rid of the poorly done
>cad-plated screws. I even replace the screws holding the coax connectors 
>and
>terminal strips to the rear chassis.
>
>Of course I am a heathen and have diverged a bit from the factory standard.
>I have an obsession with Type N and TNC chassis connectors so all of the
>coaxial hardware has been pulled and "Tisha-graded" to comply with
>everything else I use (down with the PL-259!).
>
>I am fortunate enough to work for a company that has a panel fabrication
>shop where I can use whatever I need for small hardware. Since the things
>our company make end up in corrosive atmospheres, everything is stainless
>hardware. Going to a hardware store to pick up 4-40, 6-32 or 8-32 stainless
>hardware will set you back some cash.
>
>If you feel comfortable with dropping the front panel and undoing the
>geartrain, you can really make this area shine. The front sub-chassis where
>the gears mount is cadmium plated and usually looks like hell. I have used 
>a
>metal polish with a drill mounted lambs wool buffer pad to take off at 
>least
>some of the grime and put down a protective finish of polish. Then you can
>hand polish all of the brass gears, lube up some of the totally 
>inaccessible
>places like the floating bearing ball between one of the gear shafts and 
>the
>sub-chassis plate and the spring loaded tension plates for the gear-train.
>It is amazing how many of those floating plates are locked in place or 
>where
>the tension spring has no tension.
>
>While in there, get some grommet material and make a grommet for the
>wireways between the lower chassis and the front panel. Unsolder switch
>leads and put heat shrink on some of the wires that have cracked insulation
>from the abrading contact with the circular wireway. On one of my
>restorations, nearly every front panel switches were frozen so I replaced
>the front panel switches and one bad potentiometer that could not be
>restored with DeOxIt. I removed a bit of the spring loading tension on the
>band switch as I was getting a Hammarlund version of R-390 wrist while
>changing bands.
>
>The biggest pain in the arse was making sure that the magical metal on 
>metal
>contact that gives the tuning dial on the SP-600 it's special feel was
>absolutely clean of anything that has lubricating properties and the
>electro-mechanical-magic connection near the flywheel would work
>consistently.
>
>I had not been clear on the questionable uses of WD-40 in my first post. 
>The
>only place I see it as having a value was as a water displacer. For a
>quickie wipe-down of a chassis it is fairly good at removing crud but it 
>has
>few other redeeming qualities.
>
>Oh, if you do the water bath procedure, you really need to be careful in
>powering up the rig for the first time. I would suggest checking every cap
>for a sudden departure into the realm of being a resistor or fuse. If you 
>do
>have BBOD's (and even a few poorly installed ceramic disk) capacitors the
>water may creep it's way inside of the component and short it out. I have a
>old Biddle megger that I use to do ground system testing and with a pair of
>alligator clips I give each cap a litmus test with a hand-cranked megger to
>find the definitely bad caps. BTW, this is not a good way to find out the
>capacitance, just a tool to rapidly find shorted caps.


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