Yaesu FT-990 extender boards

Discussion in 'Radio Circuits, Repair & Performance' started by WD8BWW, Nov 18, 2017.

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  1. WD8BWW

    WD8BWW XML Subscriber QRZ Page

    Does anyone have a set of extender boards for a FT-990 that is can barrow, rent, or buy. I have looked into having them made but have been told, by the folks them are making reproduction extenders, that the connectors are not available anywhere.
  2. K1MMI

    K1MMI Ham Member QRZ Page

    A set of 990 extender boards are for sale on ebay. Search for FT-990 and the extender boards will be listed.
  3. WD8BWW

    WD8BWW XML Subscriber QRZ Page

    thanks !
  4. K4OW

    K4OW Platinum Subscriber Platinum Subscriber QRZ Page

    Does anyone know of a RF Extender Board for the FT-990 to rent, borrow or buy? Thanks.
  5. W7UUU

    W7UUU Principal Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    Ping John WA1ESO... I don't see any 990 boards listed right now on eBay but he's a long-time seller of reproductions.

    Not cheap - $95 for the set, plus shipping, in "kit form" (just a lot of soldering!)

    K8PG likes this.
  6. WD8BWW

    WD8BWW XML Subscriber QRZ Page

    I believe the issues with reproductions is the lack of availability of connectors. I have only seen a couple of sales of OEM extenders and the price was around $350 and they did not last. Of all of the dealers that once serviced radios but no longer do you would think these would be out there. The sad part is without these the service/repair of a 990 is out of the question. Bottom line is I'm still looking and turning away 990 repairs.
  7. K1MMI

    K1MMI Ham Member QRZ Page

    On 11/30/17 someone bought a 990 extender board set for $362 plus $15 shipping on ebay. That was the last time I saw extender boards for sale.
    I believe in the 1990's Yaesu was selling the 3 extender board set for $275.

    I would suggest you join the Yahoo FT990 User Group.
    In the FILES area is a file GeneralTroubleshootingA.rtf. It contains general troubleshooting techniques and gives a brute force method for troubleshooting plug-in boards.

    For 26 years I have managed to repair all failures on my 990 without the need for an extender board. Most problems were on the RF Unit plug-in board and also had a problem on the Control Unit plug-in board. The other failures were on modules like the PA Board, LPF Unit board, and Regulator unit board but these modules are assemblies not plug-in boards.

    You need extender boards to re-align the 990 but it is very possible for an owner to repair a 990 without any extender cards if you have experience repairing HF radios. It just takes time.

    If you are a repair technician you need extender boards to make the repair as quickly as possible to keep the repair charges reasonable.
    Last edited: Dec 18, 2018
    K8PG likes this.
  8. K4OW

    K4OW Platinum Subscriber Platinum Subscriber QRZ Page

    Thank you for the replies. I'm at all a repair guy. My radio is at shop and that Tech doesn't have any boards at all and is also having trouble locating one.
  9. W7WLL

    W7WLL Ham Member QRZ Page

    Well, back to the well.
    I have a FT-990 that, for the circuitry issue involving the S meter, requires use of an extender board. This is a backup/spare xceiver. Do have the Service Manual.
    Am willing to pay a reasonable or slightly above reasonable price for a short term use. The cost of shipping off to the hinterlands and having someone else do the repair just makes the unit not worth it. I love this old relic.
    If you can help, please contact me direct also besides a reply here.
  10. K1MMI

    K1MMI Ham Member QRZ Page

    My approach would be to study the schematics and get a basic understanding of the circuitry involved for the S meter problem. Then decide what voltage measurements I want to take to help isolate the problem. Then I would take the voltage measurements to home in on the problem. I might take some resistance measurements based on the voltage measurements and go from there.

    I have 30 gauge wirewrap wire, so I tack solder up to 6 pieces of wires to a plug-in board at points I want to take voltage measurements. I extended the wires vertically above the plug-in board and use masking tape to identify the circuit points.

    On the bottom of the Motherboard,voltage measurements can be taken for every input and output signal that goes to and from each plug-in board.

    Without extender cards I had to be a little creative and tack soldering wires and taking voltage measurements on the bottom of the Motherboard made it possible for me to have success at repairing my 990.

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