SB-401 crystal diodes - Heath Part No. 56-26-1

[joe]

Glen:

Have done same thing with Radio Shack ln34As and no
problen  adjusting the bal mod ckt. and myfirst KWM2-A that I bought in 1971
still working great.

And now on the non technical side of things an
interesting paragraph from Rod Newkirk W9BRD
Hows DX fm Nov. 1975 about Howard Hughes,.
"Mr Hughes once was one of us, trying his early DX
wings as 5CY down Houston way. Old timers may
remember his addressing the National Convention at
Chigaro in 38 as an ARRL mmber. That was the year he
soared around the world in record time with the 20 and 40 meter aid of W2UK
W4DHZ W6CUH and other
prominent DX Hounds>"

Yeh I know, but interesting yes!

73 de Joe w0tut


----- Original Message ----- 
From: "Glen Zook" <gzook at YAHOO.COM>
To: <HEATH at LISTSERV.TEMPE.GOV>
Sent: Thursday, June 23, 2005 12:31 PM
Subject: Re: [HEATH-TEMPE] SB-401 crystal diodes - Heath Part No. 56-26-1


> At least originally they were just plain old germanium
> diodes (i.e. 1N34A or equivalent types).
>
> I have replaced the diodes in both Heath and Collins
> equipment by taking a number of diodes and "matching"
> them using an ohmmeter.  What I do is to read the
> forward and reverse resistance and put the diodes in
> "piles" with those other diodes that have similar
> readings (both directions).  The absolute readings are
> not really important, you just want them to be as
> close as possible to each other.  As far as I know,
> Heath never even "bothered" to try to "match" the
> diodes.
>
> Definitely do NOT use silicon diodes in the balanced
> modulator.
>
> As for the single diode, any germanium diode should
> work fine.
>
> Glen, K9STH
>
>
> --- Robert Myers <rsmyers at ROGERS.COM> wrote:
>
> I am in need of some crystal diodes used in the SB-401
> on the carrier generator board -- part of the balanced
> modulator. They are named D101, D102, D103, and D104
> there.  And under the chassis, one more of the same
> (D9) is used to pick off the final RF output to
> measure relative power.
>
>
> Glen, K9STH
>
> Web sites
>
> http://home.comcast.net/~k9sth
> http://home.comcast.net/~zcomco
>
>
>
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