Re: {Collins} kwm-2 balanced modulator replacement

Collins Balanced Modulator folks,

I don’t think we need to spend $60 for a set of diodes.

HP made many types of schottkey diodes, some of exotic sort and some of a more common type.  These have been suggested as replacements for the balanced modulator in our S-line radios.  I seem to remember the 1N4007 suggested as a replacement.  This diode is not as simple as the few-cents-each price would suggest.

My long time friend Brad Thompson has in the past had some Schottkey diodes, and draws upon his experience as a components engineer to have opinions and suggestions about them.  I’ve copied him on this and will forward any replies he sends me about the topic (I think he’s not on the Collins list).


On Jul 29, 2014, at 6:11 PM, Steve Berman <n6hk@xxxxxxxxxxx> wrote:

> Try Four Star Electronics in San Clemente,  CA.   They have the CA 6987 diode quad packs in stock.   They're about $60 each.
> Steve, N6HK
> -----Original Message-----
> From: Tom Worthington
> Sent: 29 Jul 2014 21:25:36 GMT
> To: collins@xxxxxxxxxxxxx
> Subject: {Collins} kwm-2 balanced modulator replacement
> I am working on an early KWM-2, S/N 200.  It has the balance modulator
> version with 1n34A germanium diodes and some are defective.
> I can replace with new 1n34a's but I would prefer to use a matched diode
> ring and upgrade to the mod 5 version but I haven't been able to find a
> source.
> Are there any recommended replacements?
> 73, Tom, NH6Y
> ...

Roy Morgan
K1LKY Since 1958

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