[Collins] Re: Collins AC power supply

[Dave Knepper]

This is a project that the Collins Radio Association totally supports.  As
the technical advisor for the CRA, Dr. Johnson is very capable of moving
such a project forward.  I am sure that Jerry would like your input.
Incidentally, Bill Abate, K3PGB, did supply a power transformer for the
516F-2 at a very reasonable price some months ago.  Perhaps, Bill and Jerry
could collaborate on this project.

Again, this is an excellent project given, as Jerry indicates, the scarcity
and escalating prices of 516F-2 power supplies.

As many of you know, the Heathkit HP-23 makes an excellent choice when
modified for the KWM-2 and S-Line equipment.  See the CRA website in the
Collins Album for an article on such a conversion:
http://www.collinsra.com/cra_album/0012/cra_0012.html

Thank you.

David Knepper, W3ST
Secretary to the CRA
www.collinsra.com

----- Original Message -----
From: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
To: "Dave Knepper" <knepper@co.cambria.pa.us>
Sent: Thursday, June 26, 2003 9:54 PM
Subject: Collins AC power supply


> Since there seems to be a shortage of 516F2 power supplies (perhaps from
> the number of KWM-2 sold with PM-2 power supplies that have self
> destructed) there might be a market for a replacement supply. What do
> you think? I was thinking about my dad's cache of miscellaneous
> transformers and there might be some transformers and chokes suitable
> for emulating the 516F-2 (with solid state rectifiers, of course,
> probably better regulation, maybe even solid state regulation of the
> +275). I'm wondering if there is a market? Then is there a market for a
> series of such supplies using NEW transformers say from Hammond that run
> over $120 each plus chokes of unknown price. Looks like such a supply
> would likely cost a bit over $200 for the raw materials. That might
> limit the market. Its just an idea I'm tossing about with many others. I
> have too many irons in the fire and too little open shop space (need to
> be building that new place with adequate shop, but my farming and my
> dad's stuff is getting in the way) to commit to such a project right
> now. But my main consulting client is facing hard financial times which
> is going to adversely affect my income so I need other projects to keep
> busy and to keep income flowing.
>
> I'm nowhere near ready to advertise such a product or even admit to
> rumors. For longevity, I'd use larger transformers, chokes, and
> capacitors that would run cooler but would prevent it fitting into the
> speaker cabinet. I might have to consider finding a larger speaker
> cabinet of complimentary design to the S-line for just such
> applications. My supply would include a power switch on the supply to
> relieve the wafer switch in the 32S and KWM-2 from the burden of
> switching the power supply (which is a failure point and hard to find a
> replacement). I don't know if I'd use a 9 pin octal connector for power,
> I'd probably use an 8 pin Jones jack and plug. That has worked on my own
> supply for decades without a problem though the high voltage is above
> the voltage rating for that connector. Probably the cable from power
> supply to radio would be needed too and its a custom thing needing some
> heavy wire for the 6.3 volts and a strand with 1 KV insulation for the
> high voltage. Maybe I could find some shrink tubing that didn't get
> stiff when shrunk and make up my own cables. Buying a minimum length of
> a custom cable was OK at Collins, totally impossible in the one man
> company.
>
> Things to think about. What do you think?
>
> 73, Jerry, K0CQ
> --
> Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
> Reproduction by permission only.