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Damaged UHF/VHF socket on FT991

Discussion in 'Radio Circuits, Repair & Performance' started by 2M0XTS, Jun 9, 2018.

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  1. 2M0XTS

    2M0XTS Ham Member QRZ Page

    Good Morning folks

    Just discovered my FT991's VHF/UHF socket (N-Type) has at some point become damaged.

    As you can see from the pictures, the fingers on the central conductor have snapped off (how? I have no ****ing idea.).

    Is this something worth trying to repair myself (replacing the socket) or would it be better to send it off to a repair shop?

    I can almost certainly repair it myself (I'm good at soldering: I regularly repair things) but given the cost of the unit I wonder if it'd be worth getting it done professionally :p


    Would it also be worth replacing the N-Type socket with an SO-239 socket for increased durability?
    Last edited: Jun 9, 2018
  2. 2M0XTS

    2M0XTS Ham Member QRZ Page

    Strike that!

    Just took it apart, and it will be easy to repair! Just some solder holding it in and there's plenty of easy access - got the socket out within a minute!

    Still, do you reckon an SO-239 would be a more robust socket?
    Last edited: Jun 9, 2018
  3. GM3ZMA

    GM3ZMA Ham Member QRZ Page

    My best guess is that some one tried to jam a PL259 plug into it.

    It would certainly be proof against having a PL259 jammed into it.

    It could be argued that the electrical performance of SO239 vs N type, the SO239 is not as good as the N.
    That discussion has been done several times here on The Zed.

    It is your radio, if fitting an SO239 socket works well in the cabling philosophy of your radio shack just do it and enjoy the radio.

    Jim GM3ZMA
  4. 2M0XTS

    2M0XTS Ham Member QRZ Page

    Nope - only person to use the radio is myself :p

    It broke while I was putting an N-type cable going to a yagi into it - it was a new connector - got a bit of resistance while screwing it on - only for a second though - I thought it was just a nick on the the the thread.

    SWR was through the roof, checked all the connections and voila, the fingers had came off. As far as I can tell, it came off during regular operation.

    The only thing I can think is if there's been metal fatigue round the bottom of the fingers - and it's just moved one too many times.

    It's also possible that the pin on my N-type cable didn't go down the centre conductor and forced it to the side - but in that case I would have expected it to bend the fingers rather than snapping all of them off: and maybe more resistance when I was tightening it up.

    Something wasn't right at any rate!

    Currently doing low signal/high noise work - will stick with the N-type just now. Got one on order, and and will replace with SO239 if the replacement breaks as well.
  5. G0GSR

    G0GSR Ham Member QRZ Page

    I have never broken an "N" type but I DID buy a radio which already had one like yours.
    There is only one way to do that and I think we all know what must have happened :)

    If you did like me and ethnically cleansed your shack of PL259 monsters, then there would be no problem ;-)

  6. 2M0XTS

    2M0XTS Ham Member QRZ Page

    But that's the thing, I was outside with only N-type connectors - there just weren't any PL259s there when it broke :p

    I've just finished looking at it under the microscope - to judge by the pattern of oxidation on the exposed surface, it looks like it cracked at some point in the past and metal fatigue on the remaining material snapped them off today when I plugged my feedline into it.

    It might be a manufacturing defect, historic damage, metal fatigue or galvanic corrosion. Its probably just been a microcrack - not hard to to, to be honest!

    There's also a nice shiny conchoidal fracture on the little slither of metal that was holding it together before today :p
  7. AA7QQ

    AA7QQ Ham Member QRZ Page

    Check to be sure your N plug is assembled correctly.

  8. AI3V

    AI3V Ham Member QRZ Page

    At 70 cm you want to EXACTLY copy the manufacturer part, and "lead dress"

    Yes, a uhf connector may work, it may also foul up the "tuneing" just enough so you loose power.

  9. WA9SVD

    WA9SVD Ham Member QRZ Page

    It probably doesn't make any difference on 2 Meters, but you would want to use a high quality connector whether "N" or UHF. Finding a "diamond" type connector may be a bit difficult; I'd demand Amphenol if possible. You may see a slight "bump" in SWR with UHF connectors on 70 cm, but many manufacturers also use quality UHF connectors on that band. If in doubt, order the part from the manufacturer; the radio is new enough that it should be available as a replacement.
    CX3CP likes this.
  10. 2M0XTS

    2M0XTS Ham Member QRZ Page

    Looks alright as far as I can tell - pin is flush with the inner sleeve.

    Just to be on the safe side, I'll dismantle it and redress it just in case! Better safe than sorry.

    Aye, managed to get a... well, I think it's the right one! The model number for the connector is P1090547: managed to get one of radioworld (a little more expensive due to P&P, but the alternative seemed to be ebay - Radioworld claim it's the yaesu connector - and I trust them more than I trust ebay ;)).

    I also decided to satisfy my curiosity by getting the remnants of the inner pin of the damaged connector ultrasonic tested at my place of work - got the NDT guy working on it in his spare time (he says it will take five minutes xD).

    I'll report back with my findings - simply because if things like this interest me, it might interest somebody else - might as well spread the word, just in case!

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