Modifications for the Kenwood TS-450
KAM-PLUS Problems!! with TS-450 & 850
A common problem when using a KAM-Plus multimode with the
Kenwood TS-850 or TS-450 occurs when the KAM-Plus is coupled to
the Accessory-2 socket on the back of the transceiver, producing
noticable distortion of the transmitted audio when using the
microphone in SSB mode..
The problem is easy to cure by disconnecting the Accessory-2
plug from the back of the tranceiver, but this meant moving the
transceiver around every time one wished to operate on SSB..
The problem is caused by the input sensitivity of the rear
Accessory-2 socket being set to high, so that it picks up very low
level noise from the KAM-Plus and associated computer wiring, this
mixes with the microphone signal, to produce the distortion.
The cure is to reduce the input sensitivity of the radio,
thus reducing the chance of distortion, also it goes without saying
that the output from the KAM-Plus must be increased to compensate
With both the TS-450 and TS-850, adjusting the input sensitivity
is straight forward and the transceiver manuals show you the appropriate
control and its location.. This is in both cases VR18 to be found on
the main board of the radio,(refer to manual) in practice I found that
it was best to adjust this control fully counterclockwise..
Then we need to adjust the output from the KAM-Plus by varying
potentiometer R28 and setting removable link (K9), this link is factory
set on one post only, (in the open position)!! this should be connected
shorting the two posts, thus putting the KAM-Plus into the high output
position, and then potentiometer R-28 is adjusted to give full power
out from your HF radio with very little ALC deflection, when the MIC
gain is in the normal operating position..
Then I am sure you will find that your problem is over, you can now
simply change from digital modes to SSB.. Remember if you have your
Beacon activated to turn it OFF or it could cause a few comments when
General coverage transmisson modification for the TS-450 and TS-690
Remove all screws of top and bottom case.
Remove two screws of front panel (left and right top sie),and loosen
two srews of front panel (left and right bottom side).
Remove all screws of digital unit ( X46-312X-XX ).
Cut the chip diode D27 (RL73) on digital unit rear side.
[ \ [
[ \__ __ [
[ \_ Bat. _ [
[ [ [ [
[ __\__ \\\\\\ [
[ \\ [ [ [
[ [_\_[ [ [ [ [ [
[ [ [ [ [ [ [ ->I- D27 (RL73) CUT THIS
[ [ [ __ __ [\\\\\_ ->I- D26
[ [\[ ->I- D25 [
[ ->I- D24 [
[ ->I- D23 [
[ ->I- D22 [
[ ->I- D21 [
[ ->I- D20 [
DIGITAL JNIT (X46-312X-XX) Component side view
Best 73 Eric St-Pascal Kam. Qc. VE2MEL
TS-450S Intermittent receive fixed
After making a careful mobile installation, WB0BQV found his TS450S to have
intermittent receive. He removed the screw that was going through the coax in
his car and made a second installation in his truck. More intermittent. With
some careful diagnosis he found that moving the coax connector up and down
caused the change in signal. With the radio opened up, I found that moving the
coax connector was breaking the contact between the wire from the center
conductor and the board (W1 in the schematic). To save on pulling the filter
board, I used a short piece of very flexible test prod wire to connect from
the center of the UHF connector to W6 on the top of the PC board. W6 jumps
over the contacts of a relay used only in the TS-690S. For added security, I
also added another wire of the same material from the ground lug on the UHF
connector to the end of D11 away from the coax connector. So now if the
flexible back panel breaks the other wire too, it won't have so much effect.
The coax connector is mounted on a 1/32" plated steel panel so is excessively
flexible in mounting. Ideally that connector should be mounted far more
stiffly for those that use real RG-8 coax.
TS-450,TS-850 feedback,ACC-2 Conn
Hi if you are using the ACC-2 connector to interface with your multi-mode
controller, you may have had a problem with your transmitted audio signal
being distorted, to eliminate this see bellow.
This modification should not affect any of the other normal operations of the
Set your meter on the radio to read ALC
PK232 OWNERS: if alsso using a VHF tranceiver, adjust the AFSK level for
proper VHF operation as expalained in chapter 3 of the operating manual.If not
adjust for proper SSB operation.
DSP - 1232 / DSP - 2232 Owners: Adjust the appropriate AFSK level control for
proper SSB operation as expalined in chapter 3 of the operating manual.
Place the TNC in calibrate mode and press K to key the radio.
Adjust VR-13 on the TS-450 or VR-18 on the TS-850 so that the meter
"Just comes off the peg" as described in the section titled "SSB Tranciever
Final Adjustments" (in the TNC operating manual).
Press Q to quit the CALIBRATE mode
Copy of service bulletin from AEA
TS-450 hidden functions
As users of the Kenwood TS-450S already known it is possible to configure the
set to personel needs by hold down some buttons during Power on.
There are three buttons listed in the manual.
The menu of Power ON + LSB/USB is listed on page 54 from the manual
The menu of Power ON + M.IN is listed on page 55
The menu of Power ON + ENT is listed on page 83
As often usual in microprocessor controled equipment there are hidden keyboard
combinations who make it possible to configure more functions then is listed in
At Power on + CLR + ENT a reset to factory defaults is taken place.
All memory programming is lost !
All filters are available (also these who are not fitted)
But there is something more!!
The receiver is able to receive from 30 kHz to 40 MHz
Transmitting is possible on
1620 kHz to 2000 kHz
3500 kHz to 4000 kHz
7000 kHz to 7500 kHz
10.0 MHz to 10.5 MHz
14.0 MHz to 14.5 MHz
18.0 MHz to 19.0 MHZ
21.0 MHz to 21.5 MHz
24.5 MHz to 25.0 MHz
28.0 MHz to 30.0 MHz
Unfortunately after power off and switching on the programming is returnd to
the most of the old values, but the 100 memory places are still empty.
So one advice before start of experimenting note the contens of the memory
places and configuration on a piece of paper, and read the "F" manual .
Until now I do not have a method to program the expanded receiving and
transmitting frequencys into the TS-450S.
If someone knows how to do this plaese let me know.
TS-450S and KAM Plus info
Hi just found out a KINK in hooking up the TS450S to a KAM Plus for AMTOR op.
You have to turn ur Delay and CAR control to 0 to get it to work mode A.
Neither control should be active when running AMTOR LSB but they are,
Micro-input RFI modification TS450-TS690 Kenwood
By Pedro M.J. Wyns, RF- and biomedical-engineer.
After buying a ts690 I got considerable trouble with the vox circuitry.
The Vox gain was always too high due to an excessive feedback resistance in the vox amplfier. Apparently a PCB-mounting failure as the schematic carried the right value. After correcting this problem I still got RF problems with nearby antennas, blocking the transmitter in TX.
lack of decent RF-filtering on the micro-input circuitry.
adding ferromagnetic cores and adjusting rc-filters on the IF-board.
remove the connectors on the right hand side of the IF board (underside transceiver front towards you). Unscrew the board and fold over to the left. Add 22 nF parallel to R282 1k on t
he micro entry close to Connector 6. Add 1nF parallel to C177 close to the IC-15 input. Add 1nF parall el to C217 close to the vox amplifier.
Remove te micro in and ground from the number 6 connector. Feed the white micro wire through a two hole ferrite core. Feed the inner conductor through a small ferrite core as well
If you might be using an MFJ (=major fucking junk) voice keyer, disconnect the shit-unshielded micro cable and replace by high quality twin balanced micro cable. Only use PTT, Mic and GND.
This concludes the mod. Don't even think of doing this without the service man ual and some smd-practice.
Go Back To The Kenwood Mods Page
Go Back To The Main Modifications Page
Go Back To The CB / HAM Radio Main Page
Go Back To The Main Home Page
Copyright © The Defpom 1997-2008