Updated: Thanks to EA5CV
C-185 should have been C-175.
Volume level mod:
If anyone picks up a Kenwood TS-440SAT and the volume level just doesn't seem right look for C-175 on the
IF Board. I picked up a Kenwood 440SAT back in July and even with the volume cranked it was barely audible. After some searching
of the schematic I found C-175 had shorted to ground. C-175 is a 220uF 10v Electrolytic. Replace it with a 440uF
16v electroltyic and you'll not only never have to replace that part again, but you'll have a wider range of receive audio
that makes shortwave broadcasts sound better than the original design.
*Note the 440 is more than likely not going
to fit so be prepared to use some small guage solid wire and some electrical tape to relocate C-175 .
The TS440 is nice. Here's what I've found out about it that isn't in the operation manual (in some random order):
Diode options: There are a bunch of configuration options controlled by clipping or inserting diodes on the back of the
control board. You get to it by taking the top and bottom covers off (a bunch of silver screws), loosening the front panel
(4 flat-head silver screws, NOT the black ones). Then you have:
diode controls in out (cut)
----- -------- ---------- ----------
D65 mode confirmation Morse single beep
D66 display resolution 100 Hz 10 Hz
D67 memory protect none on
D73 CW shift 800 Hz 400 Hz
D78 WARC 24MHx band tx disabled enabled
D79 WARC 18MHz band tx disabled enabled
D80 General Coverage tx disabled enabled
Self-Test: You can run a rather complete test of the control logic by the built-in "semi-self-test", a series of
56 routines. To run this, turn the unit on whilst holding the AM and T-F SET switches pushed in. It changes to the next test
when you turn the VFO knob clockwise. Turn the power OFF to reset the unit.
Test What it does
0 all positions in display light
1 all segments in display dark
2 all positions in display light
3 all segments in display dark
4 one digit lighted (rightmost)
5 next digit lighted
6 next digit lighted
7 next digit lighted
8 next digit lighted
9 next digit lighted
10 next digit lighted
11 next digit lighted
12 next digit lighted
13 next digit lighted
14 next digit lighted
15 next digit lighted
16 next digit lighted (leftmost)
17 beeper sounds
18 beeper silent
19 all mode LEDs ON
20 all mode LEDs OFF
The following tests change internal signals. They are most useful if you are trying to trace the circuits controlled by
You'll need a s service manual (or at least a schematic) to made reals sense of these.
23 Band select - all lines high
24 BAND select - all lines low
25 PD select - all lines high
26 PD select - all lines low
27 ENF select - all lines high
28 ENF select - all lines low
29 ENP select - a:ll lines high
30 ENP select - all lines low
31 RES select - all lines high
32 RES select - all lines low
33 CO select - all lines high
34 CO select - all lines low
35 AX select - all lines high
36 AX select - all lines low
these next tests check the outputs of the 8255 parallel port interfaces, which select several internal functions.
37 (IC2) port A all lines high
38 (IC2) port A all lines low
39 (IC2) port B all lines high
40 (IC2) port B all lines low
41 (IC2) port C0-C3 high, C4-C7 low
42 (IC2) port C0-C3 low, C4-C7 high
43 (IC53) port C all lines high
44 (IC53) port C all lines low
Following display busy lines and scan lines in the rightmost 9 digits of the display. You will push buttons to cause the
digit to change from a 1 to a 0 indicating that the associated button has been pushed.
test bit8 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
---- ---- ---- ---- ---- ---- ---- ---- ---- ----
45 LOCK AT Mic UP Mic DN PTT/AT VS1
47 (key scanner)
48 1 6 V/M VOICE
49 2 7 M>V RIT A/B
50 3 8 SCAN XIT SPLIT
51 4 9 M.IN T-Fset A=B dip3 dip4 dip5
52 5 0 CLEAR 1Mhz dip1 dip2 dip6 dip7
53 ENT DOWN UP dip8 dip9 dip10
(the digits 0-9 are on the front panel keyboard; dip2-dip10 are the segments of S50, the SSB frequency response dipswitch
on the rear of the control unit printed circuit board.)
54 not used
55 not used
Possible cure for TS440 showing dots only on display
The most common reason for the the display to show only dots, is that one of the phase locked loops is not locked. So
take of the top cover. You will be looking at the IF unit. This board is mounted in a hinged frame. It hinges on two screws
near the front pannel sides. So remove the other two screws near the final unit instead and hinge the IF board towards you.
You now uncovered the PLL unit.
There are five PLL's on this board. Each one has a pin indicating if its loop is locked or not. So get out a volt meter
and set it for 5 volts full scale. Now check pin 2 for each of the following IC's. IC18, IC1, IC4, IC9.
Also check pin 7 of IC17. If all the loops are locked, you would see a steady voltage there in the neighbourhood of 4.7
volts. If any of the loops is not locked, one of these pins has a voltage well below 1 volt.
Note the IC number so you can look up which VCO you may have to tune a bit so it will lock again.
IC18 VCO#5 T20
IC1 VCO#4 T1
IC4 VCO#3 T2
IC9 VCO#2 T9
The above are all located on the PLL board.
The VCO for IC17 is actualy one out of four different VCO's selected on the RF board. Which one of these depends on what
band is selected.
If you have display dots on all the bands, then you have no problem with the PLL made up with IC17. So you only have to
adjust either T1, T2, T9 or T20.
Now here it goes. Make sure you have an alignment tool that isn't to small or to large for the slots in the slugs in the
coils (T1, T2, etc.) Also, absolutely don't turn any other coil than the one that belongs to the unlocked PLL. If you do so
anyway without a service manual and proper equip- ment, then you are likely stupid.
Only turn the indicated slug. First turn it 1/4 clock wise and see if it is ok now. If not, turn it 1/4 counter clockwise
and see if it works. I suggest that you don't try more than one half turn either way. If you think that it needs to go that
far, it likely has an other problem.
If the display dot problem only shows up on some but not all band, send me a note and I will see if I can help you.
The correct way would be to use a good voltmeter and follow the service manual for this adjustment. But in most cases,
the above will do fine. I don't work for Kwood, I don't have a 440. Just a service manual for one. But I did cure some of
the above problems.
Also, There is a Boat-load of info for that radio here: http://www.mods.dk/view.php?ModelId=521
SUBJECT: WIRING OF TS440
USING THE ACC 2 DATA JACK ON THE TS-440 FOR DIGITAL, RTTY.
The TS-440 ACC 2 jack (13) pin can be used for your TNC hookup with
great success. The advantages are :
1. you can leave your microphone connected at all times
2. you can turn your speaker volume up and down without affecting the
RX level into
3. It keeps your whole setup simple and reduces it to one cable.
Your Mic gain will now set at 7 or 8 on it's dial. YES!
The pins used on ACC 2 are: ( see page 11 of TS-440 manual)
Data output. This is a constant 300 mv output that will go to
your TNC audio input
lead. (Note) This audio level is also
the audio output on the RCA jack used for FSK
This is where many hook up their phone patch.
The audio output may be too hot for some TNC units. if
will have to pad down this level with resistors. My KAM wants
to see 50 mv and it's seeing 300 mv. so far so good!
(4) Microphone shield (Ground)
(9) Microphone Mute. When pulled to ground, this pin will mute the
front Mic connector ** AS LONG AS THE PROCESSOR SWITCH IS OFF!**
If the switch is
left on, the audio is pumped up too high to mute.
Connect this pin to your PTT wire
from your TNC and also connect
the Cathode of a switching diode (1N4148, 1N914, etc).
The Anode of
the diode will go to pin (13). ( The cathode is the bar)
When pin 9 is pulled low by your PTT wire, the diode will cause
12 to go low enough to put the 440 into transmit. This will both mute
the front Mic jack and transmit at the same time. Works great!
If the diode is not used, and the pins are just connected
together, the front Mic
jack will mute it's self when used.
NOT A GOOD IDEA!
(11) This is your transmit audio in, from your TNC.
Setting of MIC gain on front
1. The audio level in wants to be 500mv RMS (1.5 vpp or so). For the
KAM remove its jumper inside. This will give you max audio out of
2. For the PK-232, turn up the audio output pot until you get
500mv or so RMS . You may also want to set it to make your 440
Mic gain poy read where you want it.
(MIC) will run
around 7 or 8 for digital with the KAM. I'm not
for the pk-232. more level into the 440, lower numbers on
the audio pot (MIC)
(12) Ground for audio shield
(13) Standby (transmit). this connects to the Anode (no bar) of the diode
from pin (9)
When pin (9) is pulled low, pin(13) will go low .
To sum it all up:
1. You will need:
1. diode, 1N914, OR 1N4148
1. 13 PIN DIN CONNECTOR
1. TNC cable with appropriate connectors
2. Remember to keep the processor switch OFF!
3. Set the Mic gain to 7 or 8 and look at the ALC, keep it in the
red, as per the book. Lower power, longer transmit time!
Good Luck, this hookup in being used
with 3 TS-440 radios and is
working great! Go slow and solder carefully. Please recheck
and then plug it in!