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Kenwood TS-430S with problems

Discussion in 'General Technical Questions and Answers' started by W8ATA, Mar 20, 2007.

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  1. W8ATA

    W8ATA Ham Member QRZ Page

    I have a Kenwood TS-430S complete with matching power supply, auto-tuner, and speaker sitting here in my shack which I am considering buying as a backup second rig. It belongs to a friend of mine who has not been on the air in years because of loss of hearing. The rig has been stored in a good environment for 16 years and not on the air at all during that time. He purchased it new in early 1983. There is noise  out of the audio but its only picking up signals once in a while and then they are weak. Most of the time just noise. I have tried it with the tuner in line and out and the problem is not in the tuner. It was working fine when he quit. I expect the long rest for the rig is the culprit. On transmit I can measure RF. Relays seem to be in sealed modules or are there some or a major one that is not? Are there likely causes of the problem or it anyone's guess? I can buy the rig VERY reasonably. I need some advice on somethings I can easily check. I have no test equipment except a good VOM. I know what one is worth in good working order so the purchase call is ultimately up to me.

    Thanks for any advice or info.

    73, Russ W8ATA

    "What I need to know is what I don't know".
  2. VK2TIL

    VK2TIL Ham Member QRZ Page

    I say Buy It!!!

    A nice radio (I have one, owned since new).

    The antenna relay is a known problem but it's repairable;

    The final amp board can give trouble;

    but this is also not difficult to fix (It's supposed to be only early models that do this, I think).

    You can find a manual here;

    Don't get the impression that these radios are not reliable; all radios have their little problems. The problems I've listed are known to occur sometimes and are all fix-able.
  3. AG3Y

    AG3Y Guest

    Generally, after a rig has sat around for a long time, the switch contacts become coated with a film that needs to be "exercised" off. To do this, simply work the switches a lot, and you will find the rig slowly but surely coming back to life! Bandswitches, attenuators, etc. are most likely to cause trouble.

    Some tuner clearner, or Glen prefers WD-40, can be very gently applied to switch contacts and then worked through the ranges for a while. Many problems will go away after this simple fix.

    The beauty of a rig from that era is that they are emminently repairable. The parts are actually big enough to be easily replaceable and unless you have a major failure such as a power supply component you should be able to fix it.

    One question, though, if you only have a VOM to measure things, how are you detecting RF ? How much RF and at what frequency ? Just curious.

    73, and good luck. Come back with your questions and progress report. There are lots of us here that would love to help you out.

  4. W8ATA

    W8ATA Ham Member QRZ Page

    Good question Jim. I failed to mention I have a Mirage MP-1 watt meter and very briefly measured about 80W as I recall on 20m into a cantenna. That was several days ago and I made no note of it. Was just trying to see if the transmitter was working at all. Thanks for your reply and the one from VK2TIL.


    "What I need to know is what I don't know".
  5. KA5PIU

    KA5PIU Guest


    One of the troubles with that radio is the caps are getting old.
    The dial light tends to burn out.
    And the transmit relay tends to get dirty.
    About 6 months ago I went thru mine replacing all the electrolytic caps.
    In the DC circuits I would replace the units with larger values and replaced every zener regulator with a 3 terminal unit.
    The light bulb for the meter has been replaced with LED's, white for standby, yellow for open squelch, and red for transmit.
    Green and blue are also an option.
    The transmit relay is buried inside the radio so I got an exact pin replacement and socket and put that in its place.
    It now works better than when it was new!
  6. KB0TT

    KB0TT Premium Subscriber QRZ Page

    Leave it on 24/7 ...

    Right JIM ??

  7. WB2UAQ

    WB2UAQ Ham Member QRZ Page

    Hello Russ and others
    I repaired a TS-430 years ago that had poor rx sensitivity. This particular 430 was exposed to high humidity. It was not exposed to water directly but was used during rainy field day in high humidity. Maybe this rig not having been used for many years could have soaked up moisture. The rig I repaired was returned to a dry environment but did not recover even after quite sometime. I found that the gain thru the IF was being cut back by the AGC circuit. The AGC circuit uses dual gate FETs (one gate is in the RF path and the other is tied into the AGC ckt. The AGC gate was being driven by leakage current in the circuit board. It only took microamps to make the gate voltage change and cause the gain of a stage to cutback. FET gate circuits are very high resistance ckts and it doesn't take much leakage to mess them up. I cured the problem by placing the board in an oven (used for the very purpose at work) over night and then I coated the board with a humidity sealer of some type. (HP's cure for high resistance ckts was to raise the gates up on teflon or ceramic buttons). 73, Pete
  8. AG3Y

    AG3Y Guest

    JB, you really DO have a burr in your saddle, don't you ?
  9. N8LES

    N8LES Ham Member QRZ Page

    Hello Russ,

    I have a 430S that had the same problem. Kenwood has a service bulletin about cleaning the relays to improve receive. It involves applying current through them. They also have a mod to permanently apply a cleaning current to the relays. Kenwood has changed their website and I can't find the service bulletins. I will try to post the cleaning bulletin with this reply. I have the full mod in several files if you need them. Try the cleaning first, it really helped my 430S.

    Good Luck

    The jpg is too small to read. Sorry. Let me know and I can email it to you.
  10. N3JQD

    N3JQD Ham Member QRZ Page

    Great radio. Mine is from the early eighties and had gotten bit by lightning. After an extensive repair, it works great and the Rx is even more sensitive. The point here being, that it was worth the repair bill. I say, go buy it. Especially if you can get it cheap. 73s
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