KENWOOD TS-440SAT MODIFICATIONS
Wideband Transmit & 10Hz Frequency Display & AM TX Inhibit
The diodes are located in the control unit X53-1450-00 b/2 - it is important that antistatic
precautions are observed as some components are cmos and thus prone to static damage so
use a wrist strap and operate in as static free an environment as possible. Proceed at your own risk.
Remove both covers; remove the five small screws from the stainless cover.
Photo Credit: Bill Leahy K0ZL (SK)
To enable wideband transmit 1.6mhz - 30mhz clip the lead of D80 - to enable AM TX on
Japanese version clip the lead of D77 located on same matrix as D80 - top left circle.
To enable 10Hz frequency readout clip the lead of D66 - bottom right circle.
Replace all covers - be careful not to damage wiring loom - reset CPU - hold A=B and switch
power on - frequency display will be 14.000.00 - all memories shall be wiped so take note of
memory details before reset.
TS-440SAT S.C.A.M. - Suppressed Carrier Amplitude Modulation
SCAM - DSB-TX - SSB-RX - a mode that I installed in the legendary Cobra 2000GTL
many years ago - it worked extremely well giving added range mainly due to better hearing
capability - my friend and I used it to good effect - having our own “private” mode which we
selfishly refused to distribute despite countless requests for modification information.
Reception on AM sounded fuzzy and a little distorted, but on SSB it sounded truly superb.
To enable DSB the carrier must be suppressed by switching it out of the AM TX chain, then
it exhibits the desirable characteristics of SSB, yet viewed on an oscilloscope seen as AM.
With the 440 the speech processor is the most suitable victim push button switch available.
It almost inevitably draws the short straw, and it’s no big loss, for the circuitry is a cheap
and crude excuse for a speech processor, doing little for readability, not Kenwood’s finest.
Switching Modification On The IF Board
R179 is sandwiched between IC4 and block connector 21, more exactly, directly behind and
soldered to the collector of Q41, all of which are located on the front left of the PCB.
Unsolder the right leg of R179 only, this allows easy reversal of the mod if required.
On the solder side tack a wire to the collector of Q41, that is, the now vacant R179 hole.
Solder the other end to the junction of D45, R196 and R259 all of which are located
towards the rear left of the board, R259 is located to the left of, and, just level with IC5,
D45 and R196 left of, and slightly behind IC5, easily pinpointed in the service manual.
Thread the wire through various resistors for added security and a tidy job.
Reception Procedure: Split Mode
In order to receive the AM derived DSB transmission it is necessary to program the VFO
split mode receive and transmit - note: not split frequency although possible.
Next, you have to arrange the VFO TX/RX arrangements with your fellow radio amateur.
If you decide to receive on VFO A it must be programmed for DSB reception, that is, SSB.
VFO B must be programmed with AM - and thus transmit as scam, double sideband.
I prefer to program the split memory as this gives me a fast easy setup, simply transferring
the memory contents to VFO A enabling me to toggle USB and LSB modes which is
excellent for combating various types of interference including zero I.Q. attention seekers.
To Ready Transmit
Split Mode Programmed hit PROC to switch out and suppress the AM carrier enabling DSB.
Observe AM setup instructions, set the carrier control at 12:00 o’clock, transmit and adjust
the mic gain for an on scale ALC reading on voice peaks, be ever mindful of the DSB
bandwidth now employed and always remember to check that both sidebands are vacant
before transmitting - or some om will be snarling at you like a rabid bear.
TS-440SAT ATU Modification
This Mod Enables The ATU To Operate On RX Enhancing Front-End Selectivity
Procedure: Remove both covers and the filter unit cover.
Remove the IN plug attached to the FO connector on filter unit board X51-1340-00.
Remove the four ATU retaining screws, move the ATU to the access the other connections.
Remove the plug from ATU OUT jack and install in filter unit FO jack; the other end shall
be connected to the switch unit jack later.
The Switch Unit (X41-1610-00 N-14) is the small board with yellow and black relays.
Remove both screws and both block connectors; unsolder the SO-239 antenna wire from the
socket and the two ground wires from the lugs on the SO-239.
Carefully remove the switch unit from the rig.
Unsolder the antenna wire from the PCB and clean the hole, at this time remove the solder
resist from the PCB ground trace and tin.
Cut the coax running from the ATU IN connector EXACTLY in half, then, connect the end
without the plug into the now vacant antenna hole on the switch unit PCB, connect the shield
to the previously prepared PCB ground trace.
Solder the other half of the coax to the SO-239 antenna connector, the shield to one of
the ground lugs.
Refit the Switch Unit PCB, exercise extreme care as it’s a bit fiddly, don’t force the issue.
That done, you can now plug the other half into the ATU output jack, and don’t forget to
plug the coax running from the FO jack on the filter unit, into the vacant jack on the switch
unit. Refit the covers taking care not to pinch any wire, that’s it, job done!
External Hardware Low Power Tune Mod
AT Tune (S56) switch terminal is pulled to ground via Auto/Thru (S55) push button when in
the ON position.
The switch is double pole/throw type, one side enables CW mode and the
other enables TX at 10 watts output.
Pressing AT Tune with the Thru switch OFF allows you to tune a Linear AMP
or an external AATU 80m - 10m.
ATU Repairs
When Auto Tune is enabled the motors rotate, the SWR meter indicates full scale and the
motors keep hunting. This is common on 40M and lower, on 20M and up, no problem exists.
Remove the tuner unsolder the grounded end of the tuner coil.
Check that the coil turns still read grounded, <0.2Ω. If they do, remove the 10m tuner relay
and confirm if that clears it.
Check the relays circuit, if the torroids are charred black and the PCB foil trace looks like
burnt toast, replacement or repair is required, relays, transistors and diodes must be tested
before proceeding further
Sticking Relay Problems
Lift the grounded end of the tuner coil, check if the air coil winding still reads grounded
If it does, one of the relays has welded shut
In addition, check the disk capacitors in the RF Filter TX section, these are a weak link in the chain
and are prone to failure especially on 10M, replace them with HQ silver micas.
TS-440SAT - Protecting Q33
If pin 7 (RL) of the remote connector is connected to ground current via the 14v line (14L)
this damages transistor Q33 on the IF unit and will prevent the radio from transmitting.
To protect Q33 a 4.7Ω 1/6 watt resistor should be installed in series with the RL line on
the foil side of the IF PCB, so, in the event that pin 7 is connected to ground the resistor
will open but the rig will still be capable of transmitting.
Required Part: 4.7Ω 1/6 watt Resistor ... Part Number RD14CB2C4R7J
Procedure: Remove the 7 screws holding the IF board, carefully lift the board up and flip it
forward the front of the rig to access the foil side, then cut the trace coming from pin 3
connector 19 and bridge the cut between pin 2 and pin 3 with the 4.7Ω 1/6 watt resistor.
TS-440SAT Broadcast Reception
Kenwood installed this 20Db resistive pad to reduce any overload by broadcast stations.
Pi Attenuator:
The Pi Attenuator resistive pad comprises R13 68Ω, R14 68Ω, and R12 220Ω.
They are located in the upper right area of the filter section, near L15, L16, L17, and L18,
directly left of connector 12, remove all three and fit a wire jumper in place of R12.
This will remove the pi attenuator network and restore all the broadcast receive sensitivity.
I have observed overload with 40Db+ signals but the 20Db attenuator sorts that out nicely.
Removal Procedure:
To do this, remove the bottom cover, then after removing all 9 screws, block connectors and
top shield, release the wire harnesses on either side of the board from underneath the
chassis rails. Although unnecessary you may cut the wire tie; should you choose to do so you
will not need to replace it. Carefully remove the board and flip it over to the front of the
rig, proceed to unsolder the large stainless shield. I used 1.5mm solder wick and a wide tip
40w iron; but be careful not fry the board.
It would now be convenient to examine the soldered connections within the area of VCO1;
these are the four cans on the right front side of the board contained within an open metal
shield, and it is bad connections in this area that give so many dry joint problems, it’s wise
to resolder all the connections, be mindful to check for solder bridges as you proceed.
VFO Maintenance
The main VFO dial is removed by slacking the 1.5mm grub screw by using a hexagonal Allen
key of suitable dimensions; a small amount of semi synthetic lubricant should then be applied
to the tuning shaft with the radio sitting vertically to encourage the lubrication to trickle
down into the bushing bearing.
This should be done once when the radio is new and every few years thereafter.
TS-440SAT Fan Temperature Modification
The fan is set to engage at 50°c by design, which is a little too hot for comfort, and is
controlled by two sensing circuits on the Final Unit. On the schematic, Q9 (1/2) is the
failsafe trigger activating the power down circuit in the event the final reaches 80°c it is
very unlikely to do this unless the fan has failed completely.
Q9 (2/2) is the stage that controls the operation of the fan, it is a simple voltage
comparator and may be tailored to trigger whenever you want. TH1 is a negative coefficient
thermistor, i.e., when the temperature rises the resistance goes down and this progressively
pulls the input to Q9 (2/2) lower until it is at or below the 2.26v reference that is present
on the + input of the same stage. At that point, the output flips high and turns on Q8, thus
turning on the fan. By raising the reference voltage, via R27, at the + input, the TH1 voltage
will fall to the reference voltage sooner and turn on the fan at a lower temperature, ideally
about <40°c. Replacing R27 2.2KΩ with 3.9KΩ for SSB, AM & FM modes. For Digimodes
where the duty cycle can vary from 60% - 100% here 3.9KΩ - 4.7KΩ may be considered a
more prudent choice, not forgetting, the greater the resistance the sooner the fan will
engage. I use Digimodes at 15w output so I fitted the 3.9KΩ resistor and I can report it
works very effectively, at higher output up to 4.7KΩ may be considered more appropriate.
Procedure:
Remove the bottom cover and filter unit cover on the bottom rear of the rig.
Remove the filter unit including the PCB holder to expose the final unit.
Remove all the Final Unit PCB and component retaining screws and wiring
Carefully remove the PCB, unsolder R27 replacing it with a 3.9KΩ - 4.7KΩ resistor.
Now is a good opportunity to clean off and replace the old heat sink compound on the back
of the various transistors, do not use an excessive amount of compound, and when refitting
the retaining screws don’t tighten them down fully, allow some time for the compound to
settle then tighten them down at the proper torque. Carefully check Q1 for shorts during
re-assembly, the few seconds it takes can save a lot of hassle later on.
Remember to reconnect any temporarily removed wiring being careful not to pinch.
Rx Audio Frequency Response Improvement
Located on the extreme rear left of the IF board increase C60 to .47µF or 1µF, this
will increase the low frequency response on all modes.
Decrease C51 to .01 µF, this will increase the high frequency response on SSB/CW.
Also try removing R263 tacked on the bottom of the board on early production units.
This will lower in amplitude the audio coming out of the detectors and improve the
smoothness of the audio, particularly on AM when using a good quality external speaker.
TS-440SAT Notch Filter Low Frequency Improvements
The low frequency attenuation characteristics of the notch filter can be improved by
reducing the input level to the notch filter chip IC1. To compensate for the loss of input
level, the level of negative feedback to the audio amplifier IC7 must be attenuated.
This mod is already incorporated in all models beginning with serial number 704xxxx.
Required Parts:
120KΩ, 1/6 watt resistor ... RD14CB2C124J
390Ω, 1/6 watt resistor ... RD14CB2C391J
Locate resistors R86 and R229 on the IF board (Figure 1).
Remove the 7 screws that secure the IF unit to the chassis of the transceiver.
Lift the board and flip over to the front of the rig to access the solder side of the board.
Remove both resistors from the board and replace R86 with a 102KΩ 1/6-watt resistor
and replace R229 with a 390Ω 1/6-watt resistor.
TS-440SAT Operation With The MC-85
With some TS-440SAT transceivers, insufficient modulation may occur when the MC-85
compression switch is turned on, and is caused by an excessive voltage drop across R172.
Procedure:
Locate resistor R172 on the IF board (Figure 1), directly to the left of connector 23.
It’s a good idea to cover the front panel with a protective cover to avoid scratching.
Remove the screws from the IF unit, lift the rear of the board up and flip it over to access
the foil side, remove and replace R172 1KΩ with a 100Ω 1/6 watt resistor.
FM RX Modification
The TS-440 FM receiver has 25kHz steps. Using 10 kHz steps, the bandwidth is too wide.
Using the 8.83 MHz filter on the RF board, which is bypassed in FM, solved the problem.
Required Parts: Two diodes 1N4148
Procedure:
Remove the bottom cover from the transceiver.
Locate resistor R59 and capacitor C131 on the component side of the RF board. Remove
the 9 RF PCB retaining screws, block and coaxial connectors and wiring loom. Carefully
lift and flip the board over the front panel to access the foil side of the board. Find the
junction of R59 and C131 opposite their ground connection.
Disconnect R59 from C131 by cutting the track with a sharp blade
Fit diode A with the ANODE to R59 and the CATHODE to C131
Fit diode B with the ANODE to R58/C131 and the CATHODE to C131
Remove resistor R57.
Possible Cure: TS440 Showing Dots Only On Display
The most common reason for the display to show only dots is that one of the phase locked
loops is in an unlocked condition. Remove the top cover to access the IF PCB, then remove
the other two screws near the final unit and flip the board up to access the PLL PCB.
There are five PLL's on the PCB; each one has a pin to establish the state of its loop.
Set the voltmeter to 5 volts scale then check for 4.7 volts on pin 2 on each of the
following integrated circuits, IC18, IC1, IC4, IC9 and IC17 pin 7.
If the loops are locked you shall see a steady voltage in the region of 4.7 volts.
If the loops are unlocked any one of these pins shall have a voltage well below 1 volt.
Record the IC number so you can identify which VCO to adjust to recover lock.
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 actually one out of four different VCO's selected on the RF board,
which one of these is selected depends on what band is in use.
If you have display dots on all the bands you have no problem with the PLL using
IC17, consequently you only have to adjust T1, T2, T9 or T20.
Make certain you have an alignment tool that’s a perfect fit for the slug slots in the coils.
Do Not Turn Any Other Coil Other Than The One That Belongs To The Unlocked PLL.
Proceeding without a service manual and the proper test equipment is courting disaster.
Adjust the appropriate slug one 1/4 turn clockwise and check if it is ok, if not, adjust it
one
1/4 turn anti clockwise and see if that’s ok. Do not go beyond more than one 1/2 turn
in either direction, if it needs to go that far it most likely has another problem.
Kenwood TS-440SAT PLL Unlock Due To VCO #5
The VCO and active low pass filter are encased with synthetic rubber sealant to mechanically
stabilise and protect them during mobile operation. Over time, the synthetic
compound becomes contaminated by adsorbing moisture and becoming conductive.
This causes instability and the VCO will vary in frequency which will force the loop to
unlock or cause audio warble.
This Repair Will Remedy Unlock Caused VCO 5 Contaminated Synthetic Rubber Sealant
Required Parts: (As deemed necessary)
2SC2459 (BL) Transistor
QTY. 2
DIODE
150µh
47µF
RLSBSDITT310E
Choke
El Capacitors
QTY. 2
QTY. 1
QTY. 6
1) Disconnect power and remove the top and bottom covers.
2) Be careful not to damage the speaker wires when removing the top cover.
3) Remove the two screws at the rear of the IF unit, raise the unit to access the PLL
board.
4) Remove the 8 screws from the PLL board and disconnect all the cables going to
the board.
5) Remove the board from the transceiver.
6) Remove the shield cover from VCO #5. Desolder and remove the shield from the PLL
board.
7) Carefully remove the sealant from the area of Q34, Q35, and D14.
The compound must be removed with pointed tweezers or a suitable
tool. Solvent cannot be used as this will harm the components.
8) Desolder and remove Q34, Q35, and D14 from the PLL board.
9) Check the component side of the board to make sure all the sealant in the area of
Q34, Q35, and D14 is removed.
10) Once the sealant is removed, replace Q34, Q35 and D14 with new components.
11) Inspect and resolder the foil side of the PLL board under VCO #5.
12) Install the VCO shield and solder it in place.
13) Seal the VCO with hot melt glue gun
When the area is covered, use the hot air gun to flow the glue around the
components. Be careful not overheat the components.
14) Install the PLL board in the transceiver.
15) Power on the transceiver and let it warm up for about a half hour to stabilise.
16) Set the operating frequency to 14.200 MHz
17) Adjust T20 to obtain 5 Vdc at TP11 (Lead of L40) measured with a DVM or VTVM.
Don’t use a VOM.
18) After adjusting the VCO, allow the rig to run for a couple of hours to verify stability.
19) Reassemble the transceiver.
Pot
------RF-VR3
RF-VR6
IF-VR2
IF-VR3
IF-VR4
IF-VR9
IF-VR10
Useful Adjustments But RTFM
First
Adjustment
-----------------------------------------------------------------------------------FM Microphone Gain
FM Deviation - set to 4.6KHz on dev meter
S-meter zero - set to zero with 50Ω dummy load
S-meter S9 - set to S9 with 40dbu input 14.175MHz USB
Squelch threshold - close at 12 o'clock with mode = CW and filter WIDE
CW side tone level – customisable as you like it
Beep tone level – customisable as you like it
Diode Options:
---------------------------------------------------------------------------------------------------------------------------------Configuration Options By Clipping Or Inserting Diodes On The Back Of The Control Board
---------------------------------------------------------------------------------------------------------------------------Diode Controls
In
Out (Clip Lead)
------------------------------------------------------D65
mode confirmation
Morse
Single Beep
D66
display resolution
100 Hz
10 Hz display
D67
memory protect
off
on
D73
CW shift
800 Hz tone 400 Hz tone
D77
AM TX Japanese Model disabled
enabled
disabled
enabled
D78
WARC 24MHx band tx
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-SelfTest", 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
Function
-----------------------------------------------------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 illuminated – extreme right
5
next digit illuminated
6
next digit illuminated
7
next digit illuminated
8
next digit illuminated
9
next digit illuminated
10
next digit illuminated
11
next digit illuminated
12
next digit illuminated
13
next digit illuminated
14
next digit illuminated
15
next digit illuminated
16
next digit illuminated – extreme left
17
beeper sounds
18
beeper silent
19
all mode LEDs ON
20
all mode LEDs OFF
21
receive
22
transmit
----------------------------------------------------------------------------------------------------------------------------- ---- The Following Tests Change Internal Signals. They May Be Used When Trying To Trace The
Circuits Controlled By These Signals, A Service Manual & Schematic Diagram Are Useful Here.
---------------------------------------------------------------------------------------------------------------------------------23
Band select all lines high
24
Band select all lines low
25
PD select all lines high
PD select all lines low
26
27
ENF select all lines high
28
ENF select all lines low
29
ENP select all 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 May 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
46 (none)
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
56
END
Sleeping Frequency Display
Digits
Mainly due to lack of use, some of the frequency digits “fall asleep” they become dim.
These lazy digits can be regenerated very easily, for example, select the digit in question and leave
it on for twenty minutes or so, and it will eventually awaken in all its former glory.
I myself enter 1111111 or 2222222 etc and let the rig run all night, what can I tell you, it works!
Serial Interface
The TS440 has a serial ASCII interface option and you have to insert two chips
into sockets on the back of the control unit circuit board to take advantage of this.
IC54 is an 8251A Uart, and IC55 is a CD4040 divider. When inserted, the
transceiver speaks 4800-baud ASCII in/out the 6-pin DIN connector ACC-1 on the
rear. The signals are from the 8251, but are inverted in a 74LS04 and RFI filtered
before being brought out to the world. An interface box with inverter, RFI filter,
power supply, and optoisolator, RS232 level shifters and power supply is available
from Kenwood, or you can build your own. Depending on how much your computer
radiates and how sensitive to RF it is, you may only need 5v, +/-12v, a 74LS14,
MC1488, and MC1489. If your computer has a TTL level serial port, perhaps all you
will need is the 74LS14. If you are not confident of being able to solve the possible
digital/RF interface problems yourself, the interface is probably a good buy.
ACC-1 Serial Interface
Pin
Signal
-----------------------------------------------------------------1
signal ground
2
data from transceiver
3
data to transceiver
4
cts to transceiver - computer can throttle output
5
cts to computer - transceiver can throttle input
6
no connection
SSB Frequency Response Dipswitch
Located on the back of the control unit, this adjusts the frequency response of the upper
and lower sideband modulators to compensate for component variations. Adjusting it is not a
good idea, unless you have a two-tone generator, plus you must reset the carrier suppression
adjustment if change the settings. The service manual explains this process; but I mention
it because curiosity killed the cat and cats who may have be wondering what the dipswitch
does won't scratch themselves to death by flipping switches at random to see what happens.
AGC Overshoot Mod
Problem: AGC overshoot while receiving strong SSB signals.
The symptom is audio distortion on peaks only; the distortion is reduced when the RF-gain
control is backed off.
Fix: On the RF PCB, attached to J13 pin 1 and located to the right of the gold plated
shield, foil side, change R42 470KΩ to 10KΩ, this accelerates the AGC attack response.
A.M. Selectivity Mod
Problem: Poor skirt selectivity on AM.
Fix: The cheap, stock, TS-440S AM filter, CF2, can be directly replaced with the superior
performing, AM-narrow, 6KHz filter from the Trio-Kenwood R-1000 receiver.
The part number of this filter is L72-0319-05 and it is available as a replacement part
from East Coast Transistor. This filter has more pin connections and is physically larger
than the original filter, but the IF PCB was designed to accept either AM filter, the design
engineers have anticipated that discerning hams would wish to install a good AM filter.
CF2 is located at the rear of the IF PCB just slightly to the right of circuit board centre.
No realignment is required after the AM filter is replaced.
TS-440SAT Reference Oscillator Frequency Calibration
Fix: Remove the top and bottom covers from the radio and connect an external speaker.
Connect the calibration cable between RF Unit and PLL unit, as shown in instruction manual
on page 24 in section 5-8-3.
Set VFO-A to 10.001.00 MHz LSB and VFO-B to 9.999.00 MHz USB
Pushing the A/B function button, you’ll hear a different audio tone if that 36MHz reference
oscillator is out of adjustment. Use a small flat bladed non-metallic tool to adjust trimmer
capacitor TC1; near connector 8 of the PLL Unit (refer to the instruction manual as
above) until those audio frequencies from VFO-A and VFO-B are equal.
Disconnect the calibration cable and reassemble the radio. This procedure can be done by
ear with good accuracy without any measuring equipment. WWV may be too weak to use it as
a reference signal for the procedure described in "Instruction Manual", Section 5-8-3,
however, it’s possible to use a commercial radio station of known accuracy, like the BBC, for
example, and use it as the source reference and toggle USB, LSB, it works for me!
Problem: There is no way to adjust the reference frequency oscillator with the case on.
It’s strange but true, if the frequency is adjusted with the case off, the frequency will be
different with the case on.
Fix: Drill a 8mm hole, aligned with TC1, in the left bottom half of the cover.
The alignment can be calculated as follows; vertical alignment is 6mm below the joint
between the two covers and horizontal alignment is 122mm back from the extreme edge of
the bottom left front panel. Drill where the lines meet, but remove the bottom cover and
use a centre punch to prevent the drill bit line dancing all over your immaculate cover.
To adjust TC1: Enable 10Hz readout, tune to 10MHz WWV, USB or LSB. Select W, wide on
the selectivity switch, wait until the tone modulation is present, you will hear both
sidebands and if both tones don’t match, adjust TC1 until the tones zero beat
No Direct Access To RX Input Or RX Mute
These capabilities are necessary if the 440 may be used as a slave-receiver in conjunction
with another transceiver.
Fix: On the IF PCB run a wire from the base of Q39 to J22 pin 2 remove R176 near J22.
On the X41-1610-00, (M/14) Switch Unit at antenna socket, jumper across R46 10KΩ.
The RX will now mute when the FSK IN jack is grounded.
FSK TX is possible if the AFSK is fed into the MIC jack through a 10 to 1 voltage divider.
The receiver input access can be brought out to the ACC 3 connector by connecting a 27Ω
to 51Ω 1/4W resistor to J29, pin 2 on the X41-1610-00, (N/14) Switch Unit.
A short length of wire connects the other end of the 1/4W resistor to the centre of the
ACC 3 jack, which is now the RX input. When slaved to another rig through the transverter
port, this allows the operator to simultaneously listen on 2 frequencies with stereo phones.
TS-440S All Mode Power Modification
All mode variable power via the front panel carrier control is easily enabled.
On the IF PCB cut or remove D49 which is located left of L6 with the red core and right
behind connector 36 with red and orange wires.
Now the front panel Carrier Control will adjust all modes power output.
I’m not entirely satisfied with this mod as the adjustment is a tad twitchy and sensitive.
Direct Frequency Entry Keypad Bounce
The onset of the dreaded keypad bounce can be hastened by cigarette smoke, dust and
dirt. It may be dismantled from the front panel for cleaning. The keys are dimpled metal
types and must be removed to clean the contact points using isopropyl alcohol, nothing
that leaves a residue should be used. If you can’t be bothered, an infrared remote control
interface unit that plugs into the rear ACC socket may be used instead.
The TS-440SAT requires the installation of the Computer I/F Chips (IC-10 Equivalent)
Most TS-440S rigs do NOT have these installed.
I've heard some folks debating key bounce, with the view that vigorously tapping each key
some 60 - 70 times sorts the problem as the keys are self cleaning - unverified.