SB-220 Question

[Peter A Markavage]

I had a similar problem when I tried to key my SB-200, with an early
soft-key Harbach mod, with my IC-706. When I connected the keying cable
between the transceiver and the amplifier, and turned the amplifier on,
the relay in the amp would immediately key. I put a diode in series with
the keying lead (anode lead facing the transceiver if I remember
correctly) from the transceiver. I believe the more recent soft-key
boards now have this diode(I believe it's a 1N60) in place. The Harbach
site makes mention of this diode, but can't review because Jeff is on
vacation and the site is nonfunctional for two weeks. If you have the
diode already installed, it might be shorted. Try clip leading a diode in
series with the keying lead.
Pete, WA2CWA

On Tue, 2 Jul 2002 18:35:52 -0700 John Adkins <w4kv at YAHOO.COM> writes:
> First, thanks to everybody who sent me suggestions.  I
> tried the simplest first:
>
> I noticed that when the linear is turned on, the relay
> immediately actuates, even when the TS-940s is turned
> off.  So I disconnected the relay jack from my
> TS-940s.    Voila! the relay no longer actuates when
> the linear is turned on, and there is no more plate
> current.
>
> Has the Harbach mod done something funky?  My next
> step is to check the DIN connector on the back of the
> TS-940 to make sure that I didn't short anything out
> when I was changing xcvrs.
>
> Other suggestions?
>
> Thanks again.
>
> John
> w4kv
>
>
> On Sun, 30 Jun 2002 06:40:31 -0700 John Adkins
> <w4kv at YAHOO.COM> writes:
> > I have an SB-220 that has worked beautifully in the
> > past when driven by my TS-940s.  I recently
> installed
> > the Harbach "soft-key" modification, so that the
> relay
> > circuit in my new TS-2000 wouldn't be fried.  It
> > seemed to work ok, but this a.m. I notice that there
> > is about .3 amp plate current even when the relay
> > isn't keyed.
> > > In trying to troubleshoot this (before opening the
> > case), I notice that the manual suggests that ZD-1,
> > the Zener diode may be the culprit.
> > > Does anybody else have any experience with this?
> I
> > would rather not replace the Zener if it is ok.  Of
> > course, I'm not sure that the mod is responsible for
> > the malfunction, but it's hard to ignore the fact
> that
> > it showed up soon after.
> > > I am confident that I did the mod correctly.  I do
> not
> > know whether there was plate current prior to my
> > noticing it this a.m.
> > > Thanks.
> > > John

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