SB-200 connection to TS-940S

[Peter A Markavage]

Given that pin 4 is correct and the connection in the Din plug is correct
( I don't have the schematic in front of me) . it sounds like the 940
relay jack voltage is more negative in receive than what the Harbach soft
key is expecting. Given it's more negative, the soft key/SB200 would
interpret that as a "pull to ground" and key the SB200. Early soft key
designs did not have a diode in the keying line so a number of the
transceivers would key the SB200 as soon as you turned the transceiver
power on. Later versions had a diode installed with the cathode of the
diode pointing to the transceiver. Almost any small silicon rectifier
type would work fine. I had some of the original soft keys in my SB200's
and they worked fine with all my older equipment but when I tried to
connect it to my Icom 706 or IC-756PRO II, the SB200 would key as soon as
I plugged in the relay cable. The diode in the keying line took care of
the problem. If you have a recent soft key module, you might want to
check to see if the diode is shorted or even there.

Pete, WA2CWA

On Wed, 19 Nov 2003 09:16:09 -0800 James O Keefe <n8aug at SBCGLOBAL.NET>
writes:
> When I plug the 7 pin DIN plug into the remote jack on the back of my
> TS-940,  then into the relay jack on the back of the SB-200 amp the
> relay in the SB-200 pulls in immediately even while in the receive
> mode. I am using the schematic provided in the TS-940S manual. Pin 6
> is the ALC connection, pin 4 is supposed to be the normally open
> contacts in the TS-940 that should go to the relay jack on the back
> of the SB-200.
> Am I missing something. I have a TS-450S that works perfectly with
> this amplifier.
> By the way, I have modified the SB-200 with the Harbach soft key mod
> so that I don't harm the exciter.
> Can anyone help me with this situation?
> Thanks in advance, Jim
>
> -----------------------------------------------------------
> This list is a public service of the City of Tempe, Arizona
> -----------------------------------------------------------
>
> Subscription control -
> http://www.tempe.gov/lists/control.asp?list=HEATH
> To post - HEATH at LISTSERV.TEMPE.GOV
> Archives - http://interactive.tempe.gov/archives/HEATH.html
>
>

-----------------------------------------------------------
This list is a public service of the City of Tempe, Arizona
-----------------------------------------------------------

Subscription control - http://www.tempe.gov/lists/control.asp?list=HEATH
To post - HEATH at LISTSERV.TEMPE.GOV
Archives - http://interactive.tempe.gov/archives/HEATH.html