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TS-480 iambic?

Discussion in 'Straight Keys - CW Enthusiasts' started by KD9PK, Oct 28, 2018.

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  1. KD9PK

    KD9PK Premium Subscriber QRZ Page

    Straight key works
    Bug works
    keyer works
    Iambic / squeeze does not work. when squeezed... silence.

    Manual say it does it but does not say how. Have been through all the menus, don't see anything.

    Can anybody point me in the right direction?
  2. KG7WGX

    KG7WGX XML Subscriber QRZ Page

    What kind of key are you using?
  3. KD9PK

    KD9PK Premium Subscriber QRZ Page


    And three wires.
    Ground to ring gives me dah
    Ground to tip gives me dit

    Ground to both tip and ring give nothing.
  4. KG7WGX

    KG7WGX XML Subscriber QRZ Page

    If you are actually operating the key, one side has to close before the other to set up the first element (dit or dah).

    No matter what I try with my MTR-4B or KX3, squeezing both paddles starts with one or the other - it doesn't just do nothing. And, of course, once the Iambic pattern starts, it continues until you let go of both paddles. (What it does after you let go depends on whether it is Iambic A or B mode.)

    It sounds like there is something wrong with the radio's keyer.
  5. KG7WGX

    KG7WGX XML Subscriber QRZ Page

    I did some more research on this (TS-480 group at and there is a history of complaints of the internal keyer creating extra dits / extra dahs even when used with a single-lever paddle. No mention of "it won't do Iambic", but I believe the rash of internal keyer problems indicate something wrong with the design.

    Most advise to just use an external keyer and give up on the TS-480's internal keyer.
  6. KG7WGX

    KG7WGX XML Subscriber QRZ Page

    Back to the key. Is the Bencher a BY-x or ST-x model?

    From your description of "squeezing", I'm assuming it is a BY-x model, because the ST-x can't operate as an iambic paddle.

    Also, as a last-ditch effort, you might try deliberately closing one paddle, then the other and hold both. Does the internal keyer still do nothing?
  7. KD9PK

    KD9PK Premium Subscriber QRZ Page

    Nothing to do with the radio.
    Nothing to do with the make/model of key.
    Everything to do with the key.
  8. KD9PK

    KD9PK Premium Subscriber QRZ Page

    Followup in case anyone else experiences this issue.
    The TS-480 keyer input is extremely sensitive to a low resistance ground between ground, ring and tip.

    In this case, there were multiple problems. The bencher had, over time, developed about 10 ohm resistance between the ground and each connection point. Although a single contact closure would function (either dot or dash) when the paddles were squeezed, the radio would not acknowledge that there was any closure so code stopped.
    Also, the terminals on the wire were "dubious". Just shorting the wire terminals produced the same results. Fabricated a new wire harness. zero ohnm.
    After a complete disassembly, cleaning, reassembly and adjustment the problem was intermittent as the resistance changed from one contact closure to the next. Moved grounding point on keyer from base of paddle main bracket to the spring post and contact closer remains at zero ohms.....and the radio iambic keyer works.
    Bugs fuction fine but if resistance in the circuit rises in iambic the iambic will cease to function.
  9. WC5P

    WC5P Platinum Subscriber Platinum Subscriber QRZ Page

    Good troubleshooting, and kudos for posting the root cause.

    I have noticed that the key and paddle jacks on the 480 are a bit loosie goosie. That is that the plugs do not fit the jacks very tightly. I would imagine that could possibly cause the same problem.
  10. KG7WGX

    KG7WGX XML Subscriber QRZ Page


    I just went through intermittent keying issues with some paddles which had high resistance. Resistance varied from 30 ohms to 10k or so.

    The design relied on electrical conductivity across an aluminum-steel pivot. Once I figured out that this pivot was the high resistance point, the problem was how to solve it.

    Attaching a small diameter wire to each paddle to "bridge" the pivot to the base seemed like the only possibility.

    As they weren't a major investment, I replaced the paddles. ;)

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