Should yaesu ft901dm drift constantly?

Discussion in '"Boat Anchor" & Classic Equipment' started by KG7HVR, Oct 2, 2018.

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  1. N8YX

    N8YX Ham Member QRZ Page

    The behavior is typical.

    The external analog VFO never does warm up fully, owing to nothing else in its enclosure producing heat...and also might be subject to poor regulation of supply voltage due to contact resistance of its cable connectors. Try a little DeOxIt or similar cleaner on both cable pins and DIN receptacles...see if that helps at all.
  2. K9ASE

    K9ASE XML Subscriber QRZ Page

    make sweaters
    W7UUU likes this.
  3. KG7HVR

    KG7HVR Ham Member QRZ Page

    Why does the 101 vfo work so good?
  4. KA9JLM

    KA9JLM Ham Member QRZ Page

    Or leave it on 24/7.

    When I fire up my Collins Twins for the winter, I leave them on until spring.
    WB4IUY likes this.
  5. KG7HVR

    KG7HVR Ham Member QRZ Page

    Ive tried. It never really stays put. I think its part swan! I wouldnt mind just leaving it on at all.
  6. KG7HVR

    KG7HVR Ham Member QRZ Page

    My ft8 experiment work I plug the speaker output into my laptop to decode I put the radio on Vox but the microphone on the speaker and held it there while it transmitted. Just worked japan on ft8 with tubes lol 20181210_145049.jpg 20181210_145052.jpg
  7. G3YRO

    G3YRO Ham Member QRZ Page

    I believe it's because the original FT101 series used better components . . .

    But also because they had ADJUSTABLE temperature compensation, so each VFO can be set up for zero drift individually (and re-adjusted every few years, as necessary)

    Sadly the FT101Z and FT901 were built much more cheaply . . .

    My FT101E doesn't require ANY warm-up time !

    Roger G3YRO
    Last edited: Dec 15, 2018
  8. KG7HVR

    KG7HVR Ham Member QRZ Page

    I've noticed that mine doesn't either maybe my bravo does a little bit but the display actually is the only thing that has warm up time on it
  9. WB4IUY

    WB4IUY XML Subscriber QRZ Page

    Been down with pneumonia for several days, and enjoyed reading all of the ongoing thread on this 40-ish year old rig. I've worked on many of these over the years, including my personal FT-901DE / FV-101DM setup. When I get one with a drifty VFO setup, I don't waste too much time poking around... I build a new 6v reg (be sure to include the input and output caps on those linear regs), clean all card edge connectors, re-seat all cable connections, and check for loose hardware associated with the VFO. On those with VFO changes that are jumpy (freq changes quickly over a very short period of time), use DeoxIT and really clean that gang switch under the VFO dial, that can drive you nuts. Also, clean the band switch well. Never had to tinker with the VFO temp compensation on any of the ones I've worked on. Here's my 901, been in regular use here for abt 28 years. Bought it as a junker/parts radio in 1990 and decided to bring her back to life.

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  10. KG7HVR

    KG7HVR Ham Member QRZ Page

    When you say build do you mean from scratch or just redo ?

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