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TS-430 Fixes


TS-430 Fixes

A couple of years ago, my (then) 28 year old Kenwood TS-430 started to have problems. The first symptom was that the display would count up in frequency, no matter which way I turned the tuning knob. This was intermittent  occurring mostly in the first few minutes after turning the rig on for the first time in the day. Eventually, it became worse, until it was a constant problem. At that point, I put the old 430 on a shelf and bought a new TS-480 as a primary rig.

So fast-forward to present day, and I decided to bring the 430 off the shelf and do some repairs.

I started off checking the various power supplies, and found the the 5-volt supply was sitting at around 3.5 volts. Suspecting the usual suspects, I changed out the two electrolytic capacitors tied to the 5-volt regulator. That fixed the immediate problem.

Bad Electrolytic Capacitors

Finding the caps on the back of the IF Unit, near IC-9, which is connected on the back of the tray, I removed the old ones.

Cap Locations

Note how nasty the leftover flux is from the manufacturer…

Capacitors unsoldered


Replacement caps are a little bigger... 

The new caps are a little bigger than the old ones

So after the TS-430 was operational for a while, it started developing a new problem. The audio level dropped drastically when the Notch Filter was OFF. That seemed strange, and was eventually traced to what I thought was a poor solder joint on the back of the Notch Filter Switch. I re-soldered the connections, and normal functionality was restored.

The problem was that the 8-volt switching voltage was not reaching the diode feeding the squelch transistor when the Notch switch was off.

Violet line indicates the missing 8-volt NOF signal.


While I had things torn apart, I decided to clean the pots and switches with some DeOxit. I sprayed D-5 on the switches, and Fader Lube on the pots. This led to a problem in which the radio lost sensitivity in the Single-Sideband position. I traced this to a missing 8 volt switching voltage to the wide filter when in sideband. In CW, there was no problem. A few more spritzes of deoxit on the wide/narrow switch brought it back to normal.

The Wide/Narrow switch is actually a dpdt, so separate circuits for CW and SSB. That’s why CW still worked.

Violet line indicates the missing SSW signal. 

 S18 Narrow/Wide Switch Problem...


SSB/CW Wide/Narrow switching
Next, the notch filter problem recurred. This time I found the real culprit, a hairline crack in the trace near the Notch Filter switch. I added a solid wire to bridge the gap, and fixed it (for good, I hope!)
Violet Line is the missing NOF signal from the switch.

The next item tackled was the 30-year old backup battery. While it has never given me any problems, and still read 3.3 volts, I decided that I better replace it while I had everything open.

Instead of finding a coin cell with tabs welded on, I went to Radio Shack and got a CR-2032 coin cell, and a matching holder. This will make it easier to change 20 years from now, when it’s time to change it again.

I soldered leads onto the cell holder, and put the cell in it. Then I slipped some heat shrink over the entire thing to prevent shorts, and attached it to the original terminals. The cell just lays there, sandwiched between the layers of boards.

Backup Battery

Finally, I needed to replace the wheat lamp for the meter. It had gone out before, and I had replaced it, but has since burned out again.

This time, I found a bright white LED, rated for 20ma. I used a 680 ohm resistor in series with the hot lead to drop the current down to 15 ma. The light is just right. I then glued it in place with my XYL’s hot glue gun. Works fine, last a long time…

led installed

That’s about all I could find wrong with the rig to this point. It’s working really nice now, and should be a good alternate rig.


Meter Done

Migrated Comments:

83 Responses to “TS-430 Fixes”

  1. Mark Says:

    Thanks Randy 🙂

  2. luis velazquez Says:

    I have a ts-430 also have put up in the closet, lone story short it is stuck on transmit, have done the relay cleaning i saw on you tube no dice
    check mic plug good “help” K4BTA

  3. wb0smx Says:

    Hi Luis. It seems that may be a problem with the microphone keying circuit, the Send switch, the vox circuit or the CW keying circuit. Is it stuck in transmit in all modes? That may be a clue to narrow it down. Also, check with vox turned on or off. Also with the microphone completely disconnected, along with any key or keyer, and any other plug in the back other than power and antenna.

  4. Johnson B. Diputado Says:

    Hi OM Randy,

    I am Johnson B. Diputado, licensed HAM from the Philippines with the callsign DV7DYJ. I have a QRZ account but still have not updated my callsign yet. It is still DW7DYJ.

    I also have a very old ts-430s rig. I also have the same problem with the frequency just moving upp on its own without me having to do with it. It only stops when it reaches the maximum frequency. I always experience this when I am on the USB mode. When in LSB, this problem does not arise. Is this the same as yours?

    That’s all for now and 73 DE DV7DYJ.

  5. Johnson B. Diputado Says:

    Hi OM Randy,

    Could I also ask for the schematics of the ts-430s? Thanks a lot. &3 DE DV7DYJ formerly DW7DYJ.

  6. wb0smx Says:

    Hello, Johnson. II have not seen the fault that you describe on your TS-430. It’s really strange that the mode switch (USB vs LSB) affects the symptom.

    The thing that I know will cause the frequency to move is the microphone up/dwn switches. Have you checked the symptom with the microphone disconnected? That may provide another clue. Perhaps there is a short between the USB selector line and the mic up line. That’s just a wild guess on my part.

    Good luck in your troubleshooting…

    Randy WB0SMX

  7. wb0smx Says:

    I have sent you a link via email.

  8. Johnson B. Diputado Says:

    Thanks for the guide OM Randy. Will try that setup and see if the problem persists. And thank you for the link as well. 73!

  9. steve no call sign yet Says:

    hi om, i bought a 430 in expectation of passing my test in dec with a couple of faults i’m hoping you may point me to, 1/ the mode is locked on cw and wont select any other i have given it a good dose of deoxit, but if you go to memory it will go to am or ssb or what ever was stored 2/ i have tried a reset but it dont clear so hoping it is linked, i have started by pulling the i.f. board and resoldered and replacing bad looking joints and caps, i dont think the prob is here but i have to start some where and thought i would start easy, i have nearly finished this board and i was next going to the keys unless you have a thought, thanks for listening, steve

  10. wb0smx Says:

    Hi Steve. Since none of the switches other than CW work, my best guess is perhaps the 5 volt supply that sources the data selector ic5 on the controller board. Other possibilities include perhaps connector 19 on the controller unit, or connector 18 on the switch unit is loose or needs cleaned/reseated. Another possibility is maybe the switch unit does not have a good ground connection. Maybe loosen, then retighten the screw holding it in place? Other than that, it is a matter of getting out the meter and tracing the signals.
    The switches operate by pulling the mode line for the switch low. So the following connections on connector 19 of the Control Unit should go to near 0 volts when the associated switch is pressed:
    1 – FM
    2 – AM
    3 – CW
    4 – USB
    5 – LSB

    They should each float near 5 volts when not pressed.
    Hopefully this gets you started. Good luck in getting your license next month.
    73… Randy WB0SMX

  11. steve no call sign yet Says:

    thanks randy for your super swift reply, your a star, thanks

  12. steve Says:

    hi randy, could you give me a link to the colour schematics please, thanks

  13. wb0smx Says:

    Hi Steve. I responded by email to you. Good luck… Randy WB0SMX

  14. John Duerwaechter Says:

    Had my TS 430 MARS MOD reversed by a friend. Now the meter doesn’t work. It lights up, but doesn’t move at all when receiving. also receive volume is quite a bit lower than normal.
    Any help or suggestions would be appreciated.
    73 John KC9UNV

  15. wb0smx Says:

    Hi John. Could be many things. I guess I would check for pinched wires inside, as they are pretty easy to pinch between chassis segments when folding/unfolding the boards from the radio. Other than that, sounds like maybe bad solder joint or loose connection somewhere. Hard to tell without digging into it. Good luck & 73… Randy WB0SMX

  16. AI6VX Says:

    I have a TS-430s I bought used from a guy with a problem in that the output power was inconsistent. To him it was either full 100W or 30W output. Said it was due to a dirty ALC pot (which he cleaned) but now that I own it I see I get full power into a dummy load but hardly anything when going into low SWR (1.2) and nothing at higher SWR (above 1.4). Already pulled the PA assembly and jumpered the PA base rivets so it’s not that. Any idea where I would look for the problem? (about to buy a cap kit to recap it but wonder if that’s the problem) Thanks,Dave

  17. wb0smx Says:

    Hi Dave. One of the most common problems I’ve heard of on the TS-430 is poor solder joints on the tabs of the final transistors, causing intermittent power output failures. Mine had tht problem early in its life, which I fixed by reflowing those connections with fresh solder. Never had more problems after that.
    I have not heard of anything with your specific symptoms. though. Perhaps running through the transmitter adjustments in the service manual would give you more clues?
    Good luck and 73… Randy WB0SMX

  18. Charles Lewis - KY4P Says:

    My TS-430S has developed a receiver problem. It was working well a couple of years ago. It has been stored in a semi-heated garage (50F minimum). It now only receives on 6.5 to 7.5 MHz and 18.5 to 21.5 MHz. Outside those ranges the display blanks except for the rightmost digit. – Do you have any suggestions?

  19. Jim Hancock - KB3ICM Says:

    Trying to resurrect a 430S that I got in a box of equipment. Goal is to loan to a new ham. Everything seems to work OK except a loud low frequency squeal in the audio transmit. Keying the mic or shorting pins 2-8 sends radio into transmit at full power. Some variation in ALC and call sign can be heard in transmission. Any idea where to start? Radio hasn’t been used in about 20 years. Caps maybe?

  20. wb0smx Says:

    Hi Jim. It sounds like you have tried transmitting without the microphone attached, and experienced the same oscillation problem. That points to something other than RF feedback being the likely problem.
    My first guess would be some electrolytic capacitor not doing its job. I would check the power supplies internal to the radio, and their associated capacitors first.
    Good luck with your project, and 73… Randy wb0smx

  21. Graham VE3WGW Says:

    Hi there…
    Just had a TS440 cross the bench.. Received AM and FM just fine..
    SSB and CW .. none .. Found 8 volts missing at filters. Traced to switch.. Removed all the switches, dissasembeled, cleaned and reassembeled ..
    Radio now works just fine.
    Thanks for the tips..


  22. wb0smx Says:

    Nice work, Graham. The switches can be a challenge…

  23. Guy R Skeer Says:

    Hello Steve…

    Have a New Ham’s TS430S that has only last digit lit on display. Something shook loose, or failed in trip, as unit worked fine before shipping. Sure would like to get the Fellow On-Air. Any hints for where to look?

    Thanks so much for Your Knowledge, and keeping this site!

    Guy KD6RGZ

  24. wb0smx Says:

    Hi Guy. I think you have the right idea to start. Remove covers and check/clean connectors to the boards, particularly the front panel and controller boards. Other than that, it’s a process of getting the service manual and tracking down what’s going on.
    Sorry that I can’t be much more specific without the radio in front of me.
    Good luck and 73… Randy wb0smx

  25. Jesus XE2JIV Says:

    Hi there…
    My TS-430S has developed a TX frequency problem
    10m 100w , 15m 80w, 20m 70w, 40m 50w, 80m 40 and 160n 0w

    Any help or suggestions would be appreciated

    Jesus XE2JIV

  26. wb0smx Says:

    Hola Jesus… You mention a frequency problem, but it appears from your list that it may be a power problem. With 80, 40 and 160 meters showing 0 watts out, and higher bands showing higher power outputs. On page 50 of the service manual is a diagram showing the transmit levels at various stages in the transmitter. If you are comfortable working on your own radio, I could send you a copy of the service manual.
    Good luck and 73…

  27. John Lawrence Says:

    Hi Randy.
    Dug my old 430 out of the closet.
    Having the same problem as Luis
    Velasquez’s post in 2017.
    Power up and in transmit.
    To give you a little more info,
    it stays stuck in xmit in every mode except FM.
    I shut it off, removed the mic and powered
    it back on. Same thing. I had a wattmeter and dummy load attached before I ever started, and
    I noticed there was no output. I switched to FM
    as I have the FM430 board installed, hooked up
    the mic turned it on and keyed it. Still shows no output on either of two wattmeters.
    So aside from what you offered Luis, what more can I try?
    73….de KB9HRS

  28. wb0smx Says:

    Hi John. It’s very difficult to troubleshoot over email. If the rig was working when you put it away, I guess I would clean all switches,(especially the “Send” switch). If that doesn’t work, then check all electrolytic capacitors, and look for pinched wires and wires shorted to ground.
    Good luck and 73…
    Randy wb0smx

  29. Ben Says:

    Hi Randy,
    My ts-430s exhibits strong birdies on 1.927, 3.852, 7.190, 14.375, and some other frequencies on upper HF ham bands. They are internal, not from the power supply. As RF gain is decreased they also decrease. Could you offer some ideas what circuits could be causing it? Or maybe it’s normal for this rig? I use it so infrequently that I never noticed them before.

    Thank you
    73, WB4A

  30. wb0smx Says:

    Hi Ben. I’ve had my ts-430 boxed up on a shelf for a good while now, so I cannot confirm whether my rig also has birdies at those frequencies. Perhaps someone else will see your question and chime in. There is an owners group on, at where you may find more help.
    Good luck, and 73…
    de Randy WB0SMX

  31. Fred Fleming Says:

    Thinking about buying a TS-430 from a friend. He was up front with me and said the rig received ok but no TX. The price is only a $100.00 but I have not been into solid state repairs and have no test equipment other than a VOM. Any suggestions on what may be the problem? I need to get back into HF but the wife is tight with the money. Any help is appreciated. Any service manuals available I could use a link.
    Fred Fleming (KM5S)

  32. wb0smx Says:

    Hi Fred. I love my TS-430. Having said that, it is not my daily use radio. I have a TS-480 that is about 10 years old now. The TS-430, after I restored it, is reliable as long as I use it regularly. But if it sits unused for a few months, the switches need to be cleaned again to restore reliable operation.
    I would not recommend a broken TS-430 for a person that has not had much experience troubleshooting solid state equipment. Its age falls into the area where you can expect many poor solder joints, bad capacitors, dirty switches and the results of prior owners attempts to fix.

    I would recommend obtaining a newer used radio that is not so old that it is experiencing the typical failures of a 30 – 40 year old radio. Something less than 10 years old is likely to give you many more years of reliable service.

    Barring that, my next choice would be a much OLDER rig, probably a Heathkit. They are still very serviceable. There is room to work on them, and they are mostly tube-based equipment. There are several good user groups that will help you troubleshoot. Much more than the TS-430.
    Good luck and 73…
    Randy WB0SMX

  33. W Rusty Lane Says:

    Well, it’s now 2020 and I am a new Ham and found a Kenwood TS-430S for $250.00 with the original Power Supply unit. I will take my General test next week and will receive my Kenwood TS-430S. Thanks for posting about the TS-430S as I will probably be taking it apart and replacing the meter incandescent light with a proper LED bright white 5mm one. 73 from K9POW.


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