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Re: [Amps] SB-220 Submerged

To: "Paul Whatton" <paul.whatton@ntlworld.com>, <amps@contesting.com>
Subject: Re: [Amps] SB-220 Submerged
From: "Gary Smith" <wa6fgi@sbcglobal.net>
Reply-to: Gary Smith <wa6fgi@sbcglobal.net>
Date: Thu, 4 Aug 2005 08:17:28 -0700
List-post: <mailto:amps@contesting.com>
A fine suggestion and "how to"  from Paul.
Want to point out that most of us do not think of it as such, but pure and 
clean water is a corrosive if left alone to do its slow deeds.
IE, rust. Nothing more than water added to steel.  Add salt, the effect is much 
quicker. (Ugly corrosion.)
Just a couple of thoughts.
73,
Gary... wa6fgi

  ----- Original Message ----- 
  From: Paul Whatton 
  To: amps@contesting.com 
  Sent: Wednesday, August 03, 2005 4:56 PM
  Subject: Re: [Amps] SB-220 Submerged


  Hi Bill

  An amateur friend of mine has a business hiring out PMR radios. As you 
  can imagine they sometimes come back from hire in a terrible mess having 
  been dropped into everything you might imagine, the least of which is 
  dirty water. His solution is to drop them into an industrial ultrasonic 
  cleaning bath and then, as Gary suggested, oven bake them dry. Over the 
  years he has "subjected" hundreds of radios to this treatment and, 
  without fail, if it is done carefully, they work fine afterwards. The 
  ultrasonic cleaning bath is filled with tap water and a splash of some 
  commercial additive is added. I can find out what it is if you want.

  One day he suggested I might want to clean my transceivers by dropping 
  them in the bath. I was very reluctant but, what the hell, I trusted 
  this old friend. I did remove the mains transformers for reasons which 
  will become clear but otherwise I dropped whole rigs in the bath and 
  then oven dried them. Bingo! Not only did these radios work but they 
  worked better because the ultrasonic cleaner had got to all the contact 
  surfaces in the plugs, relays etc. The front panels sparkle like they 
  are new.

  The only reason I removed the mains transformers was drying time. When 
  water gets inside the windings it is difficult to dry out.

  What have I learnt from this? Water itself, even tap water, isn't a 
  problem provided that the radio is FULLY dried out. Dirty water, the 
  kind you have experienced is a problem because the impurities make it 
  conductive. Even if it is dried out you may experience problems from 
  conductive deposits and/or corrosion.

  What to do? In my opinion you should wash the SB-220 very thoroughy. I 
  think that means taking it out into the yard and very thoroughly hosing 
  it down. There is nothing to loose by doing this, it already has dirty 
  water in it. If you can find someone with a big enough industrial 
  ultrasonic cleaner then put the whole amp in it. Then dry it. And then 
  dry it again. It will take hours and hours., days and days. By all means 
  oven bake it or use the hot Sun. Total drying is vital. Last week I 
  dropped a friend's 2m mast-head preamp which was badly corroded and, he 
  thought, a write off, into the ultrasonic cleaner for 20 minutes. After 
  3 hours oven baking there was still sufficient moisture inside the tuned 
  circuits to de-tune it. After a week in the hot Sun in my shed it worked 
  perfectly. Thorough drying is crucial.

  Good luck! With patience I am sure you can save the amp.

  Paul G4DCV

  Bill Smith wrote:

  Other than the obvious "dry it out" what should a guy
  do to get a SB-220 back on after having been submerged
  in a basement for over a week?

  A friend of mine was away when a very bad storm
  flooded his basement.  The water flowed up the stairs
  and out the front door!!  So much for living at the
  bottom of the hill and having no check valve on his
  sump pump connection to the city sewer!!  Against city
  rules many people had connected their sump pumps to
  the city sewer.  That in turn over loaded the system
  as well as the water coming down the street filled a
  lot of basements.
  73,
  Bill

  Bill Smith KO4NR


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