About two months ago there were a number of posts on this subject. Suspected
and identified causes of the problem included the relay (rl 1005), the relay
switch (s1002), pc board connections, and the "tx-gnd" phono plug. Also, hot
switching of the amp due to the delay in the FT-1000 relay was suspected.
There is an easy solution that will eliminate all these possible problems.
Don't use the phono plug output at all, but take the output from pin 2 of the
"Band Data" DIN connector, with pin 3 as the gnd return. This comes from
Q1029, the transistor switch that drives the "tx-gnd" relay. It will switch
all amplifiers that don't require sinking a very high current, and don't
present the switch with a couple hundred volts in the open state. This
probably includes all modern amplifiers. The relay switch can then be left in
the off position to eliminate the unnecessary clicking of the relay, and this
mod will also eliminate the 15 ms or so delay caused by the mechanical relay.
My thanks to "Chip" at the Yaesu booth at Dayton for an enlightening
discussion.
Bert, VE3QAA
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