Please be very careful with your transcievers, and we accept no
responsiablity for any damage that may be incurred, and this
modification may, and proably would be cause for any WARENTY to be
This Modification allows for the Kenwood TS-440s transceiver to have
the data audio on PIN 11 of the 13 pin DIN connector ACC JACK 2. Later
models may or maynot have a correction for this, but my PK-232, or for
that fact NONE of my TNC's would drive the audio to the PIN 11 of ACC
JACK 2. Encountering this problem, and having another H.F. transceiver
I have been using the REMOTE connector, and using an audio input to the
AFSK IN RCA type connector. This would allow me to use the same cable
with my TS-180s also. Anyway this modification moves the wire's from
the AFSK IN to the ACC 2 connector. This should only take about 20 to
30 minutes to preform this change, and most of the time is used up with
the removal, and replacement of the THREE covers of the transceivers
The circuit boards to work with, are called:
DISPLAY UNIT (X54-1870-00) (C/4) This has the ACC 2 JACK.
SWITCH UNIT (X41-1610-00) (M/14) This has the AFSK INPUT.
The eaiest way is to remove these two boards 4 screws hold the ACC 2
JACK, and 2 screws hold the AFSK INPUT board in and they are located at
the rear of the transceiver. If you are interested in following the
SCEHMATIC in your manual, the leads you will be working with are ANI,
and GROUND which is the PURPLE LEADS, and the FSI lead and GROUND,
which are the GREEN leads.
The problem is that when kenwood designed this rig, they brought
the DATA INPUT(ANI) from the ACC2 JACK to connector J25 of the IF UNIT.
This coming in after the Processor, and Microphone Amplifier does not
allow sufficent amplification of the signal, thus very low, or no audio
at all. What this modification does is swap at the rear of the RIG the
FSI, and ANI signals, Which also could be done on the IF UNIT board,
and for some may actually be eaiser. In my case the leads were just a
bit too short to allow this modification to be accomplished on the IF
Be shure to have on a work bench, and NO POWER APPLIED!
Remove the TWO BOTTOM covers, One MAIN cover, and the smaller
cover to the REAR of the transceiver.
Remove the TOP cover.
Remove the FOUR screws holding the AUTOMATIC ANTENNA TUNER.
Place the transceiver on it's side with the BOTTOM towards
you, and the FRONT to your LEFT.
Being very careful, remove the antenna tuner and allow it to hang.
Remove the TWO SCREWS that HOLD the AFSK INPUT board.
Remove the FOUR SCREWS that HOLD the ACC 2 JACK board.
Carefully from the inside of the transceiver, pull these TWO
Near the Bottom edge of the ACC 2 JACK board, is a TWO lead
connettor, unplug this. The leads should be PURPLE.
On the AFSK INPUT board, there is a 6 PIN connector, unplug
this. The leads you will be working with are GREEN in color.
Note how the PURPLE leads are connected to the connector itself,
and remove these two leads by inserting a very small screwdriver
into the slot on side, and being very gental, push the leads out
one at a time.
Now remove the GREEN leads the same manor.
Insert the GREEN leads into the 2 PIN connector, the BLAC lead
is the GROUND, and the WHITE or perhaps YELLOW is the AUDIO lead.
Insert the PURPLE leads into the 6 PIN connector, noting that
the smaller lead is the AUDIO lead, and it connects to PIN 2,
the other lead, being BLACK goes into PIN 1.
Now reassemble in reverse order the BOARDS, and start at STEP
11, and work in reverse to STEP 1.