HP 935 5.1mp digital camera. Error message: "SD card is locked".Need a cure to take pictures again.

Discussion in 'Digital Point & Shoot Camera' started by onederer, Jun 12, 2005.

  1. onederer

    onederer Guest

    I have an HP 935, 5.1MP. If no one can answer this question, I will
    have to throw this camera in the trash can. HP wants $35 just to say
    Hello to me. This is like throwing money down the toilet. The only
    thing that they want to talk to me about is selling me a used
    (refurbished) camera for just a few bucks less than what I paid for this
    one. And yes, they are telling me to throw away this camera. Some
    customer service!

    The camera will no longer take pictures anymore. It's _neve_r been
    dropped, and has been used approx 4 times during a two year period. The
    camera now tells me that the SD memory card is locked (which it isn't).
    A brand new memory card produces the same results.

    Does anyone know how to "unlock" the memory cards? I need a fix for
    this camera. I am not talking about the switch on the side of the memory
    card. This is a software error, or the sensing switch for the card is
    not functioning.

    onederer, Jun 12, 2005
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  2. onederer

    Whiskers Guest

    The 'write protect switch' seems to be a purely mechanical thing on the
    card itself, and peering into the slot on my camera [1] it looks as though
    the 'detector' inside the slot is a micro-switch.

    I'm guessing, but perhaps there is a little bit of dust or something inside
    your camera that has the micro-switch jammed in the 'write-protected'
    position? Another guess would be that the electrical part of the switch
    inside the camera is faulty.

    The SD card slots don't look as though they can be dismantled for
    maintenance; whether it makes economic sense to change the card-slot in a
    camera, I don't know; HP's attitude suggests that from their point of view,
    it isn't. An independent repairer might be able to do it at a price you
    could tolerate - but that too is just a guess.

    If the alternative is to junk the camera anyway, perhaps it would be worth
    trying a puff of compressed air from one of the cans sold for cleaning
    computers? That might dislodge whatever is jamming the mechanism. Even
    more drastic, a cotton bud moistened with the liquid used for cleaning
    tape-deck heads or record-player pickups?

    I'm still new to digital cameras, but I have seen 'digital camera care
    kits' in the shops. I'd also be inclined to ask the shop for advice, if
    you haven't tried that already.

    [1] My camera is a Samsung, not an HP, but I expect the SD card slots are
    much the same.
    Whiskers, Jun 12, 2005
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  3. Almost certainly it's the switch in the camera. The SD card switch is
    purely mechanical, on both ends. Could be that the switch in the camera
    has oxidation on the contacts, the contacts could be bent, or their
    could be a speck of dirt in it (assuming that it must be closed for
    writing, which I am not sure of, and the SD organization doesn't publish
    the specification, you have to be a member to get it).

    For point and shoot cameras, they are not going to open the camera and
    attempt a repair; if it's out of warranty they are going to trash it.

    Camera makers love SD because it's small and cheap, but Compact Flash is
    much better.

    You could try blasting some air in there, as someone else suggested, but
    this is a long shot. OTOH, you don't have much to lose!
    Steven M. Scharf, Jun 13, 2005
  4. Steven M. Scharf wrote:
    What makes you say that CF is much better? SD can be made without the
    troublesome switch, e.g.:


    and the contact arrangement strikes me as much better than CF. The OP
    could try this brand of card in his camera. (We've used them without

    David J Taylor, Jun 13, 2005
  5. onederer

    Whiskers Guest

    There is this <http://www.sandisk.com/pdf/oem/SD_SDIO_specsv1.pdf>

    Whiskers, Jun 13, 2005
  6. It isn't the card that's the problem here, it's the switch on the SD
    card socket. I don't think that there is any camera maker that does not
    implement the WP functionality.
    Steven M. Scharf, Jun 13, 2005
  7. onederer

    ASAAR Guest

    The OP could try using an MMC card instead, which should bypass
    any switch on the SD socket. It wouldn't be as fast as an SD card,
    but it might not be any slower if used in an HP 935.
    ASAAR, Jun 14, 2005
  8. onederer

    Rudy Benner Guest

    Interesting, how close is the compatibility between SD and MMC?
    Rudy Benner, Jun 14, 2005
  9. Good idea. I wonder how smart the camera's firmware is. If the switch on
    the socket is stuck in "WP" mode for SD, is the firmware smart enough to
    ignore this when an a MMC card is inserted, because MMC doesn't support
    WP? I wouldn't count on this.
    Steven M. Scharf, Jun 14, 2005
  10. onederer

    ASAAR Guest

    The only difference I'm aware of is that of speed, and I believe
    that that is due to SD cards having a wider data path. I know that
    in PDAs, MMC cards work, but are much slower moving files and
    loading programs. Some ancient device that was designed to work
    with MMC cards *might* not be compatible with SD cards, but any
    device designed to accept SD cards should work with MMC also, but
    with limitations. One example would be in cameras claiming to allow
    unlimited length videos to be made. If the card isn't fast enough,
    usually that video length is very limited, such as to a length of 20
    seconds. I've been told that some cameras don't stop recording, but
    simply drop images when the card can't keep up. In such a camera,
    MMC cards would be guaranteed to produce horrendous videos. Still
    images wouldn't suffer, other than shot to shot delays might be
    longer than if SD cards are used.
    ASAAR, Jun 15, 2005
  11. onederer

    ASAAR Guest

    It would depend on how the software was written and what the
    actual hardware problem is, but I'm not sure about switches on the
    socket. It's not as if the SD card has a protuberance that pushes a
    switch in the card socket. The switches are on the SD cards
    themselves. They're fairly small, so many people that use SD cards
    may never have noticed them.
    ASAAR, Jun 15, 2005
  12. The switch on the SD card doesn't do anything electrically, it's just
    mechanical. The switch is on the socket; it looks at the position of the
    mechanical switch on the card. It's similar to how the write protect on
    cassette tapes work (though these are breakaway tabs that cannot be
    undone, except with a piece of tape).
    Steven M. Scharf, Jun 15, 2005
  13. onederer

    ASAAR Guest

    Well, I was right about there not being a switch-activating
    protuberance on the card, and you appear to be right that the real
    switch is in the socket. Looking at an SD socket in a PDA it
    appears that when either an MMC or SD card is inserted, a mechanical
    part in the socket tries to move into an opening in the card, which
    would either be uncovered by moving the switch on an SD card into
    its 'write-protect' position, or which doesn't exist at all in MMC
    cards. So the good news is that the switch in the socket can't be
    stuck in the 'WP-enabled' position, as that would prevent the card
    from being inserted, and if it was stuck in any position, it would
    be in the 'WP-disabled' position. But that simply indicates that
    what's broken isn't the mechanical plunger part of the switch in the
    socket. Even if some crud found its way into the socket and jammed
    the switch, preventing the plunger from moving, that would only
    (falsely) indicate a 'WP-disabled' condition. It might be that
    another part of the switch failed, or the failure is somewhere else
    in the camera, and if that's the case, even MMC cards might appear
    to be Write-Protected. But if an MMC card could be found, it would
    still be worth trying, but I now agree with your conclusion that
    success shouldn't be counted on.
    ASAAR, Jun 15, 2005
  14. Not necessarily. It depends on whether the switch in the socket is
    normally closed with no WP, or normally open with no WP.

    Usually these set-ups will have an input to the microcontrolled pulled
    high with a resistor, and the switch closing will connect the signal to
    ground (active low). There could be a piece of solder, or other fragment
    of metal stuck between the contacts of the switch, etc. It's a hokey
    arrangement. They should have used optical sensing, but this is more
    expensive than a mechanical switch.

    One more reason to stick with Compact Flash.
    Steven M. Scharf, Jun 15, 2005
  15. onederer

    ASAAR Guest

    No, I think you're missing the point. It doesn't matter whether
    the switch is normally closed or open. Either way, the mechanical
    plunger part isn't causing the problem, which was the point. If a
    normally closed switch indicates 'WP-disabled" but a piece of dirt
    prevents the switch's contacts from touching, the card would appear
    to be write-protected. Similarly, if a normally open switch
    indicates 'WP-disabled' but something broke inside that switch that
    prevented the switch from opening, it would also indicate a
    write-protected card. In fact, it doesn't have to be a problem with
    the switch at all. A bad solder joint, or some conductive crud on
    the PCB could cause the problem too.

    I see that your next point matches what I just got through saying,
    so I guess we're pretty much in agreement.

    Because CF sockets don't have switches? They can have other
    problems, and I've seen a couple of people that claim to have had
    serious problems due to accidentally bending pins. Some people
    prefer CF cards because they're physically large. Others dislike
    them for the same reason. Card types don't matter very much to me,
    although I'd go out of my way to avoid using MMC and MS cards. More
    important to me is that the camera be able to use standard AA (or
    AAA) cells. Other people prefer Li-ion rechargeables. Even better
    are devices (and I know a few) that let you use either type.
    ASAAR, Jun 15, 2005
  16. onederer

    peter Guest

    Looking at pictures of the cards, SD and MMC it looks as if the MMC has
    no detail where the SD has the wp switch, so the camera needs its switch
    depressed to enable write. Looking inside my usb card reader, this seems
    to have a simple contact arrangement, leading to the thought that
    contact closed = write enable. So you have either as suggested elsewhere
    a camera circuit board fault, dirty contacts, or a card and switch that
    are too close to the limit of operating tolerance. Have you tried adding
    a couple of layers of tape to the side of the card to press the switch a
    bit harder? If that works you could build up a card with glue just for
    this camera and forget about the write protect feature
    peter, Jun 17, 2005
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