[ARC5] Cleaning MFP resin.

[Leslie Smith]

Hello Richard,
Your observations are of great interest to me.  You seem to have direct
experience cleaning MFP from equipment.  My experience is from reading
only.  

Below, you mention a product called Fosterite.  This sound suspiciously
like a product we call transformer varnish.  At work the electricians
have a large pot of this.  They dip re-wound motors in this "thick brown
stuff".  I easily imagine General Radio dipped their transformers in
this stuff.  Yes, the result is a hard lacquer.  And yes, the
electricians dip their gear in this stuff.  They don't spray it on, or
use a paint-brush.

I used a combination of kerosene and inox to clear away the material
between the main chassis and the VFO sub-chassis.  I had to do this
because the goop (the material I called MFP) is everywhere.  But maybe
it's the content of one of the capacitors.  I'll look closely and say
(one way or the other) if that is so.  I'm looking for some way to
explain the difference between your observations and what I see here.

I have several frequency meters, but I gave away the best one.   A
friend, VK2GL, built a Paraset, a replica.  Ex RAF, Geoff took some
trouble making the Paraset.  He covered the coils in beeswax (as per
original) and so on.  He even tracked down the fellow who made these and
spoke with him.  I gave him my very nicest frequency meter (I would say
prisine - apart for the "outer") because a Paraset needs to be on the
right frequency, yes?  Ha!  Geoff gave the meter to our local club -
Westlakes!  Anyway I'm getting the other sets I have going - and
especially setting the crystal to frequency.   I have (on loan) a
rubidium frequency standard, so I can check the accuracy of the crystal
itself against a reliable standard.  (I understand WWV, but a standard
on my bench is much easier to use.  Also I can say that out government
cut funding to VNG (local time and frequency standard) some years ago. 
I'm fascinated (unreasonably) by the crystal oscillator in this
instrument!  

Thanks for your helpful info.
Found a Bristol wrench (thanks to DS) in a "secret" panel in front of
the PS unit.


   73 de Les Smith
   vk2bcu at operamail.com

                                                         o-o-o

On Mon, Oct 2, 2017, at 20:00, Richard Knoppow wrote:
>     I will add to this that I have had some luck with paint remover. I 
> mean the jell kind. Takes several applications and several hours but 
> will eventually get the resin off.  I am sure there was a solvent for it 
> but I have not found any mention of it.
>     Another note: United Transformer made a line of transformers and 
> chokes treated with Fosterite. I can find almost nothing about this. The 
> illustrations show dipped units. General Radio used transformers that 
> were dipped in some sort of thick brown stuff, a hard lacquer. I think 
> this may have been Fosterite. I would be glad to know more. It may have 
> been some sort of MFP but is thicker.
> 
> 
> -- 
> Richard Knoppow
> 1oldlens1 at ix.netcom.com
> WB6KBL
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