Re: {Collins} kwm-2 questions



Tom, please do not wash your M-2 in the dishwasher. That risks latent death
and many problems down line. Water wicks rapidly into laminates on
transformers. It also wicks into the ceramic trimmers and brings in soap and
dirt with it and that dirt and soap stay even if the water does dry out -
which is problematic also.

Washing also tends to accelerate corrosion and leaves residue in sensitive
ground connections.

I cannot tell you how many pieces of Collins gear we have repaired that have
stuck or corroded trimmers and rust in the laminates years later.

Looks good now and dead later.  There is no substitute for good old elbow
grease and a controlled cleaning with the correct stuff.

You have gotten some good replies on the other parts of your question, so
clean 'er up and enjoy.

One other thing you might consider doing is carefully - being sure to not
bend or damage other components - loosen every ground screw (lugs and tube
sockets and shields etc. ) - make sure that the washers and screw move a bit
and then retighten. The industry has learned an incredible amount about the
physics of intermetallic connections and the resulting galvanic action that
results from work function induced micro-currents locally in grounds or any
metallic contact. This info was not available to Collins when the S-Line was
designed and built - nor did they anticipate that the rigs would still be in
operation 55 years later.

Screws are stainless, washers are bronze and the chassis is aluminum... and
then you have some plated steel mixed in occasionally.  Makes nice little
batteries - and the ground contact resistance goes up with the corrosion
that results. Break the ground mechanical contact, move it and remake it,
and you will have a much better contact. We are seeing an increasing amount
of RF and performance problems that are very difficult to run down, and
moving the grounds makes them disappear.  If the unit has been in
uncontrolled storage, or is dirty and not used for a long time, I would make
a preemptive strike.

Just be sure you keep track of where you have been, be careful to not leave
damage behind. Also make sure you tighten everything again.

Good luck and let us know how it goes.

Regards

Bill Carns, N7OTQ
Trustee K0CXX
President, Collins Collectors Association
Editor, Signal Magazine
Wimberley, TX
512 618 2762  (Cell)
512 847 7010  (Home)



-----Original Message-----
From: Collins [mailto:collins-bounces+wcarns=austin.rr.com@xxxxxxxxxxxxx] On
Behalf Of Tom Worthington
Sent: Monday, July 21, 2014 7:53 PM
To: collins@xxxxxxxxxxxxx
Subject: {Collins} kwm-2 questions

I am the new owner of a KWM-2, my first Collins, that a friend found at a
garage sale in Florida along with its power supply and microphone.

 

The S/N is 200.

There are a couple of things that I believe are not standard.  It has a
Waters Q Multiplier Notch Filter 340-PT

Is there a source of information about this?  Also, the RF Gain control has
two stacked pots.  The lower has a clear plastic ring for adjustment.  Any
ideas on what it might adjust?

 

My plan is to replace the electrolytic caps, at least one of them has
exudate, and give it a good washing.  In the past I have put electronics of
this era thru the dishwasher using dishwasher detergent (after removing the
tube, meters and paper capacitors).  Is this a reasonable cleaning technique
to use?

 

Are there any suggestions on how to gently first apply power after I get it
cleaned up?

 

Thanks and 73, de NH6Y

Tom Worthington

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