SB-201 & TS-440S

[Stewart Lyon]

There are are two cautions regarding interconnections between the TS-440
and the SB-200/1.  Both the keying line and the AGC circuits were
designed for tube-type rigs and will over-stress the associated circuits
in the TS-440.

 A very good and cheap solution for the keying is offered by Harbach
Electronics in his SK200 "SoftKey" circuit.  He uses a clever hookup of
an optocoupler that requires about 1mA at 1 Volt through the TS-440
keying circuit.  The circuit costs all of $14 and works very well on both
solidstate and tube rigs. See Allen's full catalog at:
http://www.harbach.com
If you do install SoftKey, I would recommend using two stacked 3M
mounting pads to mount the PCB rather that drilling a mounting hole as
instructed.

The now defunct "Heathkit Technical Journal", April '98 discussed the AGC
problem and suggested installing a 5K thumbwheel pot across the SB-200
AGC line. The top of the pot goes to the -200 AGC line, the bottom to gnd
and the wiper out the AGC jack to the TS-440 AGC input. The method of
adjustment is to tune for full power on CW with the AGC _disconnected_
then adjust the pot for -8 volts (max).  The AGC line is then connected
to the TS-440.  The 4.7K resistor in the AGC line is shorted out or
removed. The only problem with this mod is that the amp now does not
supply enough AGC to a SB-100 or -400.  -- it's now only suitable for
solidstate rigs.

Hope this helps.

73, Stu - W6CUX
Winnetka, CA
ARRL Life Member

On Sat, 31 Jul 1999 07:21:49 -0400 Gary Franklin <franklin at NET-LINK.NET>
writes:
>Anyone familiar with the interconnections required to use the SB-201
>with a Kenwood TS-440S?  Any cautions?
>
>Gary  K8BKB
>

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