diode replacement

[John Campbell]

Hi everybody...With respect to Jim's question about diodes, the fact
that Heath refers to them as "crystal diodes" makes me tend to think
that they may be of the early germanium type (maybe something in the
1N34A family). A thought occured to me concerning your inability to
achieve carrier null....In the SB-401, when you are in the CW mode,
there is a voltage applied to the carrier null circuit to deliberately
unbalance it (resulting in RF output) whenever the key is closed. Take a
look at the circuit description in your HW-101 and see if they are using
a similar scheme. If so, it could be that some of this voltage is being
applied (leakage) continuously, resulting in the inability to null the
circuit.

                     Good Luck....John (W8JNC)



>Date:         Tue, 12 Jan 1999 20:00:12 -0700
>Reply-To:     n7kbj <n7kbj at ONEIMAGE.COM>
>From:         n7kbj <n7kbj at ONEIMAGE.COM>
>Subject:      diode replacement
>To:           HEATH at LISTSERV.TEMPE.GOV
>
>Hi all - I'm still trying to solve the problem of my carrier that won't
null
>in my hw-101.  I've now replaced the 200 ohm null pot, and that
improved, but
>didn't fix the problem.  So I guess the next step is to replace the 4
diodes
>in the null circuit.  So, here's my question:
>the manual simply lists these diodes as 'crystal diodes', heath part
no.
>56-26-1.  In todays parlence, what am I looking for to replace them
with, and
>how much of a voltage/current rating do I need??
>And while I'm looking for advice, does anyone know of a source for the
slip-on
>type tube shields that were used in the hw-101?  the tube sockets don't
have
>the lugs for the 'twist and lock'  type of shields.
>Thanks in advance!
>Jim - N7KBJ
>
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