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VCR Runs eratically

Discussion in 'Electronic Repair' started by Robert LaCasse, Apr 27, 2004.

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  1. I have an old Panasonic VCR Omnivision, and it runs erratically when a
    tape is inserted, changing the display from SP to SLP erratically.

    I haven't seen the problem yet, other than it has some near black
    brown-outs on tthe inside of the casing.

    It worked fine the last time I used it, then it sat as a clock for about
    a year, and when I powered it on, it started with grinding sounds, and the tape
    ran erratically, the wheels anrd reels turn erratically, even after many tape
    cleanings, and manual capstan cleaning.................

    Any hepl would be appreciated.

    ThanX in Advance

    Bob

    Triad Productions-Fantalla(c)~EZine~ParaNovel
    National Association of Assault Research
    WWWeb>> http://nwo.naar.be
     
  2. It's an old machine, probably needs belts and other routine service.
    Specifically the tape is shifting slightly in the tape path and the control
    track is lost, so the machine defaults to SP speed. It may even be on the
    verge of "eating" the tape. When the control track comes back in, it
    switches to EP (SLP). Cleaning the audio/control head may help, but as I say
    the machine should probably have more general maintenance done.

    Mark Z.
     
  3. Also possible it's having power supply problems common in these older
    Panasonics.

    See the VCR Repair Guide at the site below if you consider it worth
    spending time on.

    --- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
    Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
    +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
    | Mirror Site Info: http://www.repairfaq.org/REPAIR/F_mirror.html

    Important: The email address in this message header may no longer work. To
    contact me, please use the feedback form on the S.E.R FAQ Web sites.
     
  4. At first, it didn't play at all, just groaning sounds, no picture to be
    tracked. A bunch of cleaning did nothing, so for (4 hours) I tweaked the 3
    tracking head screws, to get a consistent sound, then a consistent picture
    stream, but it still only plays SP, which is OK, since it is a 1988 machine.

    Rubbers are fair, no slip, cleaned spools too, I couldn't get it to play
    and recognize the tracking part, so I'm stuck with the SP.

    ciao

    Bob


    |>It's an old machine, probably needs belts and other routine service.
    |>Specifically the tape is shifting slightly in the tape path and the control
    |>track is lost, so the machine defaults to SP speed. It may even be on the
    |>verge of "eating" the tape. When the control track comes back in, it
    |>switches to EP (SLP). Cleaning the audio/control head may help, but as I say
    |>the machine should probably have more general maintenance done.
    |>
    |>Mark Z.

    Triad Productions-Fantalla(c)~EZine~ParaNovel
    National Association of Assault Research
    WWWeb>> http://nwo.naar.be
     
  5. I think the "Omnivision" models predate the switchers we all love so much.

    Mark Z.
     
  6. Chris

    Chris Guest

    I've done lots of these Matsushita made VCRs. These symptoms always
    point to bad Capacitors in the power supply. The main culprits are the
    4 1000uf caps in the 5v and 14v lines. Next is the 4.7u on the primary
    side and the 1u/50v in the opto-isolator circuit. Best to replace all
    the caps, as the rest are probably not far from failing too.

    Chris
     
  7. Yes, there were Omnivision models before them but Omnivision was used for
    a long time after and certainly includes the lovable switchers.

    I guess a model number would clear it up!

    --- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
    Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
    +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
    | Mirror Site Info: http://www.repairfaq.org/REPAIR/F_mirror.html

    Important: The email address in this message header may no longer work. To
    contact me, please use the feedback form on the S.E.R FAQ Web sites.
     
  8. |>
    |>> I think the "Omnivision" models predate the switchers we all love so much.
    |>
    |>Yes, there were Omnivision models before them but Omnivision was used for
    |>a long time after and certainly includes the lovable switchers.
    |>
    |>I guess a model number would clear it up!
    |>
    |>--- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
    |> Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
    |>+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
    |> | Mirror Site Info: http://www.repairfaq.org/REPAIR/F_mirror.html
    |>
    |>Important: The email address in this message header may no longer work. To
    |>contact me, please use the feedback form on the S.E.R FAQ Web sites.
    |>

    The model number of this Panasonic "Omnivision" model is PV-3700-K.

    I did not grasp the expression [Switchers], except as the era when
    people might have strayed from panasonic products?
    Triad Productions-Fantalla(c)~EZine~ParaNovel
    National Association of Assault Research
    WWWeb>> http://nwo.naar.be
     
  9. Yeah, the 3700 uses a switch mode power supply (switcher).

    Now if I could only remember the original symptom.

    (They nice thing about Alzheimer's is you get to meet so many new people!)

    This model does tend to flash black & white to color when playing tapes as
    the power supply begins to fail, especially when in slow motion play, but
    you could certainly have other symptoms - a weak clock display, servo
    problems like yours, noise bars in the picture when the motors run, lines in
    the tuner video, etc.

    Mark Z.

    --
    Please reply only to Group. I regret this is necessary. Viruses and spam
    have rendered my regular e-mail address useless.


     
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