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JVC VCR

Discussion in 'Electronic Repair' started by Femme Verbeek, Oct 12, 2004.

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  1. My JVC HR-DD 858 VCR has the following problem. It shuts down the power
    (stand by) just a few seconds after switching it on. When i put in a
    tape, the power comes on, it lays the tape in correctly and then spits
    it out again.

    I payed the investigation price for the repairshop. Their conclusion is
    that the drum unit needs to be replaced at a price for which I can buy
    three new VCR's.
    I have the strong feeling that this is their standard answer, in case
    they can't find the problem. Anyone an idea what could cause the
    problem, or if their conclusion could be right?

    tia.
    Fem Verbeek
     
  2. NSM

    NSM Guest

    "Femme Verbeek" <FV2003 ( at ) cyberjet ( dot ) nl> wrote in message
    | My JVC HR-DD 858 VCR has the following problem. It shuts down the power
    | (stand by) just a few seconds after switching it on. When i put in a
    | tape, the power comes on, it lays the tape in correctly and then spits
    | it out again.
    |
    | I payed the investigation price for the repairshop. Their conclusion is
    | that the drum unit needs to be replaced at a price for which I can buy
    | three new VCR's.
    | I have the strong feeling that this is their standard answer, in case
    | they can't find the problem. Anyone an idea what could cause the
    | problem, or if their conclusion could be right?

    Is it the moisture sensor causing this?

    N
     
  3. Is there any? If so shouldn't that give an error message? My house is
    very dry. It just shuts down normally.
     
  4. NSM

    NSM Guest

    "Femme Verbeek" <FV2003 ( at ) cyberjet ( dot ) nl> wrote in message
    |
    | "NSM" <> schreef in bericht
    |
    | > Is it the moisture sensor causing this?
    | >
    | Is there any? If so shouldn't that give an error message? My house is
    | very dry. It just shuts down normally.

    The VCRs I am used to have this. If it malfunctions it might cause this.
    It's supposed to eject the tape until the moisture condition is removed,
    since running will cause damage. A very cold tape in a warm room may result
    in condensation problems.

    N
     
  5. Any idea where this sensor is located, or how to verify this.
     
  6. Is the moisture sensor not meant for a camera? This is just a normal
    home vcr for playing vhs tapes.
     
  7. It could be many things, only very rarely the "drum unit".

    See the VCR Repair Guide at the site below. "Play and Record Mechanical
    Problems":

    http://repairfaq.ece.drexel.edu/sam/vcrfaq.htm#vcrprm

    --- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
    Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
    +Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
    | Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

    Note: These links are hopefully temporary until we can sort out the excessive
    traffic on Repairfaq.org.

    Important: Anything sent to the email address in the message header is ignored.
    To contact me, please use the feedback form on the S.E.R FAQ Web sites.
     
  8. Forget the sensor. Unless you just brought the VCR in from freezing
    cold, it's something else. It wouldn't shut down but say "DEW" in the
    display.

    See my previous post.

    --- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
    Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
    +Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
    | Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

    Note: These links are hopefully temporary until we can sort out the excessive
    traffic on Repairfaq.org.

    Important: Anything sent to the email address in the message header is ignored.
    To contact me, please use the feedback form on the S.E.R FAQ Web sites.
     
  9. NSM

    NSM Guest

    | > Is the moisture sensor not meant for a camera? This is just a normal
    | > home vcr for playing vhs tapes.
    |
    | Forget the sensor. Unless you just brought the VCR in from freezing
    | cold, it's something else. It wouldn't shut down but say "DEW" in the
    | display.

    Many VCRs have no display now and no 'Dew' light, so shutdown is the only
    option. And clearly this unit has a fault.

    N
     
  10. Yes, but why is everyone jumping on the sensor bandwagon? :)

    --- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
    Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
    +Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
    | Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

    Note: These links are hopefully temporary until we can sort out the excessive
    traffic on Repairfaq.org.

    Important: Anything sent to the email address in the message header is ignored.
    To contact me, please use the feedback form on the S.E.R FAQ Web sites.
     
  11. NSM

    NSM Guest

    | > Many VCRs have no display now and no 'Dew' light, so shutdown is the
    only
    | > option. And clearly this unit has a fault.

    He is looking for suggestions. This is one. You may have others.

    N
     
  12. awknod

    awknod Guest

    The problem with your JVC vcr has nothing to do with the drum unit,
    accepting the tape and shutting down is about 95% mode switch problems, or
    voltage regulator STK etc.......... clean the mode switch, or have someone
    clean it for you.
     
  13. James254

    James254 Guest

    <SNIP Links to Sam's very good web site>

    Hi,

    The short answer is that the repair shop's conclusion may be correct.

    The longer answer is that the HR-DD858 is a Hi-FI VCR with "Dynamic Drum".
    Simply this feature tilts the angle of the whole drum assembly (Read: Upper
    and lower drum, including drum motor) so you can cue and review a tape
    without the noise bars that are typical with units that do not have this
    feature. It also has a audio delay circuit so you can listen to the sound at
    normal speed while performing cue at x7 speed!

    If the capstan motor, drum motor or the Dynamic Drum do not initialise
    (Read: Send capstan FG, Drum PG or DD Tilt signals back to the
    microcontroller) when the unit is brought out of stand-by then you will get
    the problem you mention.

    So, as Sam say's it's possible for the drum to cause this problem, but there
    are many other possible causes. You need to speak with the repair shop and
    ask them to explain to you what's wrong with the drum unit that it needs
    replacement. If you're satisfied with their answer then they are probably
    correct.

    However if it sound like bullshit and smells like bullshit, chances are it's
    bullshit.

    Perhaps the unit is in timer mode? Are there and strange lights lit on the
    front of the unit that were not lit before?

    Hope this helps!
    James
     
  14. Hi,
    Very correct.
    The drum starts to rotate. I did not see any other movements.
    Could it be that one of the motors is mechanically blocked. So helping
    it at startup could unblock it?

    I still have to pick up the vcr at the shop to have a better look.
    It is a very large electronics shop, selling many brands, having their
    own repair shop.
    Chances are that the man at the desk can not answer any questions about
    the investigation.
    I would have noticed that.
    Certainly. You confirmed clearly that the repair shop could be right.
    There is another JVC specialised repairshop here in the area. But that
    would take another investigation fee.


    thank a lot
     
  15. I tried to measure the voltage supply, see if it is weak. But it is hard
    to disassemble the thing and find a good measuring point on the board. I
    measured it over a resistor that becomes fairly hot. During tape inlay
    the voltage went up a few volts from (what was it again) 6 to 8 V.
    Nothing unexpected I think.


    thanks
     
  16. Note that if they are really in the business of *selling* new equipment,
    they aren't going to be much interested in repair.

    --- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
    Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
    +Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
    | Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

    Note: These links are hopefully temporary until we can sort out the excessive
    traffic on Repairfaq.org.

    Important: Anything sent to the email address in the message header is ignored.
    To contact me, please use the feedback form on the S.E.R FAQ Web sites.
     
  17. JVC dude

    JVC dude Guest

    Hi For what its worth we here in the UK have had many problems with the
    DD drum system.
    They all have problems with the small black plastic gears inside the tilting
    mech. Basically the plastic splits from the metal shaft to the outside,
    possibly due to being too tight on the shaft!
    Basically the mech when initialising runs fwd then back whilst reading the
    opto pulses. If the count isn't correct/fast enough an error is assumed and
    the VCR will go into standby mode. The gears seem to split easier when the
    machine is used in hot and/or smoky environments.

    As to diagnose this, you will usually hear ticking noises from the DDrum
    when first powering up. If the gears are ok then it will sound smooth and
    you need to look elsewhere.

    I have had NO problems with mode switches on these units!

    For whatever reason JVC do not supply new gears, and only a new drum is the
    answer. As you say, it costs a fortune.
    Having tried a few times to swap bits around to make a good unit, I can tell
    you its dammed tricky to setup all 4 adjustment points so that it will track
    the tape properly.

    I think there may be a work around by disabling the gears, at least the unit
    would initialise, but auto tracking and still/slo-mo might be adversely
    affected.

    Anyone else any experience on these DD mechs?

    AW
     
  18. I did not hear any ticking. So far the VCR worked always without error.
    Just 1/2 a year after the end of 4 years warranty it breaks down.
    Thanks to all for the answers.
    I learned that this vcr has a tilting mechanism for the heads in order
    to avoid striping, but is also weak in construction.
    I'll try a closer inspection on this mechanism, but chances are that it
    is beyond repair. Your answers convinced me that the repair shop could
    be right.

    regards
    Fem Verbeek
     
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