[ARC5] BC-455 cleaning (My experience)

[Leslie Smith]

  Hello Andrew,
  I'm replying to your question from my EXPERIENCE with a single BC-453.
  I got this set in poor condition; I bought it to 'rescue' the tuning
  gang.
  I decided to rescue the set - it was in a condition that could only
  make the set better.
  I based my method on the experience of those who reported putting a
  "tube" set in a dish-washer.

  I removed the 6 tubes, 3 IF transformers and the RF coil box.  That's
  all.
  My method involved hot soapy water, followed by washing in tap water,
  followed by spraying with bathroom foam (Dot's Bath and Tile Cleaner).
  The label said,  "contains quaternary ammonium compounds".  After this
  used a clean paint-brush to work at the dirt under the chassis.
  This means everything around the valve sockets.  Everything was foamy
  white, and the Al. chassis has a few "cleaner" streaks where Dot's
  mixture leaked out the various screw holes.   

  I followed this with more tap water (from a garden hose) and then a
  50-50 mix of iso-propyl alcohol and water.
  Finally, warm air + 2 days in the sun.

  The result?  I can't tell, because my set has an intermittent fault
  around the 12K8 local oscillator circuit.
  When I turned my set on it didn't work.  I found the 12K8 wasn't
  working.  The set worked after I replaced it.
  BUT - I don't believe the 12K8 was faulty, because some time later the
  set failed again.  
  Probing one L.O. pin (probably the anode) made the set work (for a few
  days).  After that, the fault returned.

  The well-informed (and very modest) D.S. gave me some good advice.
  I loosened and re-tightened screws on the I.F. transformers (etc) and
  put a small amount of good quality lubricant in the bearing of the
  tuning capacitor.
  
  My set has run for some months now.  I must add that I run my sets on
  a 60V B+ line.
  (If I was starting again I'd take that up to 90V; some advocate 135V,
  other a higher voltage.)
  I CAN'T say my method worked or failed, but you have my experience -
  based on a sample of one.
  However I suspect I got the set because it was faulty before I began
  the cleaning process.
  
If any-one has a dirty, non-working "junker" they want to donate to a
scientific cleaning (using the afore-mentioned cleaner by "Dot")  I'll
pay the cost of postage to get the set to my place for cleaning and
de-bugging on my work-bench.  I want to try running a set on DC-DC
voltage doubler, followed by a second doubler.  That should give me a
100V B+ supply, from the 24V filament supply.  

  I apologize for a longer posting.

 
  73 de Les Smith
  vk2bcu at operamail.com


On Mon, May 25, 2015, at 05:57, Andrew Kopke wrote:
> Hello, A very dirty BC-455 followed me home today ,and I was wondering if
> it was okay to immerse the set in hot soapy water after I remove tubes
> and every plug-in can . There is what looks to be a crystal mounted in a
> can  in the bottom compartment . It looks like one of the capacitor cans
> ,but is square . I wondered how well that would stand up to water as well
> because it is soldered in place.
> Many thanks
> ______________________________________________________________
> ARC5 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/arc5
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ARC5 at mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

-- 
http://www.fastmail.com - The professional email service