N0HI

[ Home ] [ Station ] [ 4-811 Amp ] [ TS440 Info ] [ Propagation ] [ Pictures ] [ Cluster Node ] [ Log Search ]
This is a collection, in no specific order, of information on the Kenwood TS-440 and TS-440S.  Some of this information is from experience and not printed in the manual, but you should read the manual first (or at least keep it around for reference).  I take no responsibility for any of your modifications or repairs; this is simply my information and experiences with the radio.

More added soon...

Just for fun, read the eHam reviews of the TS-440 or view Universal Radio's TS-440 accessories.

Basic Specifications

  • Band coverage: 160-10m (with WARC bands)
  • Modes: SSB, CW, AM, FM, AFSK
  • Output: 100W final amplifier stage, 40W AM
  • Power: 13.8VDC/20.5 amps
  • Microphone: 8 pin (MC-43S included)
  • Extra features
    • 100 memories
    • Noise blanker (dual mode)
    • Keypad entry
    • Processor
    • IF notch
    • AT-440 automatic antenna tuner

Top

Diode Changes

  Feature Diode Cut
D49 SSB power control with carrier knob No ssb power control Control with carrier
D65  Mode selection  First Character in Morse  Beep
D66  Display accuracy (extra digit) 100Hz  10Hz
D73  CW shift  800Hz  400Hz
D78  WARC 24MHx band tx  Off On
D79  WARC 18MHz band tx  Off On

Top

Computer Interfacing w/ ACC1

TTL levels, baud rate 4800, ASCII Serial (8 data, 1 start, 2 stops).

ACC-1
1 GND Signal ground
2 TXD Data TS440 to PC
3 RXD Data from PC to TS440
4 CTS PC ready (radio output)
5 RTS Radio ready (radio output)
RS232
2 RXD Data TS440 to PC
3 TXD Data from PC to TS440
4 DTR Data Terminal Ready
5 GND Signal ground
7 RTS Request to send

Top

Audio Modifications

C60 to .47uf or 1uf (low frequency response SSB/CW/AM/FM)

C51 to .005uf (high frequency response SSB/CW); roll-off becomes 1.4dB at 3KHz

Top

SSB Distortion

Local the two bias adjustment holes in the heatsink.  The hole nearest to the antenna jack is VR1 (driver); the other hole is VR2 (final).  Increase the driver bias to about 250mA.  Increase the final bias to about 400mA.  Consult the service manual for more on this one.  You can also help out your collectors by increasing voltage supplied to 16VDC.

Top

Thin transmit audio

C135 on the IF from 0.1uF to 0.47uf.  This one makes a big difference.

Top

Key Clicks

The TS-440 is near famous for key clicks.  The output timing is too quick, almost 500uS.  Change C168 on the IF to .22uF, and change R225 to [up to] 43K Ohm.  This modification may lag on the initial character (especially if you use BY1 to key your amplifier) when full break-in is used.  I'm still working on a way to prevent this.

Top