MFJ 490 Keyer to FT-818/818ND

Discussion in 'General Technical Questions and Answers' started by G0TUE, Apr 15, 2021.

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  1. G0TUE

    G0TUE Ham Member QRZ Page


    keyer jumper
  2. N3PM

    N3PM Ham Member QRZ Page

    Maybe it isn't there. The diagram shows one at the "key out jack" section. The only diagram I have shows one. Maybe it changed and I'm wrong.

    I wrote this just before your pic
    Mike N3PM
  3. KG7WGX

    KG7WGX XML Subscriber QRZ Page

    The manual says it is on the rear of the unit near the CPU and the RCA key jack and that you have to move it to the two pins closest to the RCA jack for grid-block keying. For modern rig keying, it should be on the two pins furthest from the RCA jack.

    The schematic shows that the jumper is a selector, so if there is no jumper on it, the keyer won't work in either keying mode.

    If you have to turn the unit upside down to get at the inside, then the back panel is near the "front" of the picture, with the pots on the L. I think I see a 3-pin header and it is empty.

    If the jumper is missing, it might have fallen off in shipping. Turn it upside down and shake it and see what falls out. ;)

    I think these are almost universal, so you can "rob" one from something else for testing.
    Last edited: Apr 17, 2021
  4. G0TUE

    G0TUE Ham Member QRZ Page

    I will check this out when I get home, my optimism is rising. I will report back.
  5. G0TUE

    G0TUE Ham Member QRZ Page

    I'm at work at present but I have found an image online which shows a jumper, mine dose not have this, it may
    have fallen off in transit or was never fitted, but this would cause the issues discussed above, I will check.

    Attached Files:

  6. G0TUE

    G0TUE Ham Member QRZ Page

    Conclusion and topic closed :))

    Thank you all for your time and thoughts on this matter, it was down to the missing jumper!!!!
    fitted a wire one, and success - keys the rig up nicely and everything else it's supposed to do.
    My thanks:

    Thank you again.

    Ray G0TUE
    W4NNF likes this.
  7. KG7WGX

    KG7WGX XML Subscriber QRZ Page

    Fantastic! I hope it gives you many years of service.

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