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This Mod will change the TS-940 time constant from approximately 1
second to .022 second. This means that the ALC will no longer
impose its own characteristics on your audio response; the ALC will
now follow your own sylabbic rate and emphasis. Usually the average
output will increase, which will drive a linear amplifier harder
(or at least those meters will swing higher!!). Use caution in this
mod and have another Ham-friend check around your TX frequency for
splattering while you are QRV.
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The TS-940 has a 10uF cap (C31) and 100K resistor (R104) which make
up the time constant for the ALC. This tends to reduce the output
power for the duration of the ALC time constant (or till the circuit
charges up again). Then it starts all over again on the next word.
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This procedure allows modification to the control PCB (X53-1420-11)
in the TS-940 WITHOUT having to remove the board. Remove the bottom
cover and locate the control PCB. Locate R137 and R104. These are
located in the upper right hand corner as the rig faces you upside
down (near VR-3). A service manual is helpfull for locating parts!!!
Using an Exacto knife, VERY CARFULLY scrape off some insulation
from the top of these two resistors. Now tack-solder a 1/8 watt
2.2k ohm resistor from the top of one of these resistors to the top
of the other. The time constant is now changed. Reassemble and
enjoy a superb rig.
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