[Kenwood] TS-430s Power Down mode

[Rob Stampfli]

My understanding is that grounding the center pin, pin 6, on the
ACC socket on the back of a Kenwood TS430S, should cut the rig's
power output to 50W.  The instruction manual that came with the rig
ignores this entirely, but the service manual has directions for
setting the PO to 50W with pin 6 grounded and other instruction
manuals I've downloaded from the net also allude to this "feature".
I suspect it was incorporated to support the AT-250 auto tuner,
but this would be useful to me when connecting my 430 to a linear
amplifier.  

Unfortunately, my 430 doesn't seem to cut its back power with pin 6
grounded.

Does anyone know if there were any changes made to the 430 in this
regard?  Was this perhaps a later alteration?  My unit was purchased
in November, 1984.  Any idea how to make this feature work?

Thanks in advance,
Rob Stampfli / KD8WK