Yaesu FT-902dm has memory issue.

Discussion in '"Boat Anchor" & Classic Equipment' started by K3LEO, Nov 28, 2016.

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  1. K3LEO

    K3LEO Ham Member QRZ Page

    My ft 902. Memory does not save frequency,,the ground still works on only tx,not Rx,,,for split working...vfo dial works good.. problem is with the buttons below the main vfo dial..please send any ideas or thoughts.thanks Leo K3LEO
  2. KH2G

    KH2G Guest

    I my have a failing memory myself but it serms I recall a small lithium battery used for memory. If so, change rest and should be good to go.
  3. K3LEO

    K3LEO Ham Member QRZ Page

    no battery in this rig,,,issue is ongoing when plug in to ac.
  4. W9GB

    W9GB Ham Member QRZ Page

  5. IK3SSO

    IK3SSO Ham Member QRZ Page

    [Quote = "K3LEO, posta: 4.050.938, membro: 727.041"] My Memory ft 902. non salva frequenza ,, terra funziona ancora su un solo tx, non Rx ,,, per scissione di lavoro ... sintonia VFO funziona bene. . problema รจ con i pulsanti sotto il dial..please VFO principale inviare tutte le idee o thoughts.thanks Leo K3LEO [/ quote]

    curiosity, found the memory problem? .. Mauro
  6. N8YX

    N8YX Ham Member QRZ Page

    Bumping the thread up from the archives:

    My FT-901DM just started behaving in this manner. Won't store anything when the "M" button is pressed.

    If one looks at the schematics, the Memory Write function is performed by bringing Pin 6 of the Memory Module connector to ground. The path is through S06 (momentary switch "M") and RL02's wiper, then through its normally closed contact which is tied to ground.

    The relay in question is of a type that's used throughout the FT-90x and accessories. They're small and occasionally fail due to oxidized contacts. This one is mounted on "Select SW Unit" (PB-1718C) and one must dig into the radio to fix or replace it.

    When I get a bit of spare time I'm going to pull my '901 out of the lineup and attempt to clean its contacts. The thread starter (if still around) might do same with his '902.
  7. KL7AJ

    KL7AJ Ham Member QRZ Page

    Where do I insert a lithium battery in my cranium?
  8. K3LEO

    K3LEO Ham Member QRZ Page

    please note what you find out and post a few pics the issue..thanks
  9. N8YX

    N8YX Ham Member QRZ Page

    Checked my '901's switches over the weekend. They're working correctly - Pin 6 of the Memory Unit (orange wire) is pulled to ground every time the "M" button is pressed.

    I had another Memory Unit on-hand - courtesy of a donor FT-902 which I'm resurrecting - so I tried it. Operation was restored.

    One thing I noticed about the new one: When the rig is powered up, the "M" LED is always lit. Looking at the Memory Unit schematic, this is the PLL Unlock LED. It should be illuminated if the Memory Unit is working properly.

    My bad one didn't solidly illuminate that LED after a long period of use. There's a momentary flicker now and again.

    'LEO: How does your '902's "M" LED behave?
  10. K3LEO

    K3LEO Ham Member QRZ Page

    Hi, mine is a solid led light, but it doesnt save to the menory button when depressed, it will to the rx button but not the tx,, also the when the tx is pressed it the vfo is locked. hope you understand. thanks for help

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