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Photo Forum / Digital Photography / Point & Shoot Cameras / June 2005HP 935 5.1mp digital camera. Error message: "SD card is locked". Need a cure to take pictures again.
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. Thanks > 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 [quoted text clipped - 15 lines] > > Thanks 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.  Signature-- ^^^^^^^^^^ -- Whiskers -- ~~~~~~~~~~ > 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 [quoted text clipped - 13 lines] > card. This is a software error, or the sensing switch for the card is > not functioning. 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! [] > 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! What makes you say that CF is much better? SD can be made without the troublesome switch, e.g.: http://www.kingmaxdigi.com/news/news_product/news_p20040303.htm 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 problems). David > 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 > problems). 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. > 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. 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. >> 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 [quoted text clipped - 3 lines] > 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. Interesting, how close is the compatibility between SD and MMC? > Interesting, how close is the compatibility between SD and MMC? 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. >>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 [quoted text clipped - 3 lines] > 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. 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. > 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. 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. >>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 [quoted text clipped - 7 lines] > themselves. They're fairly small, so many people that use SD cards > may never have noticed them. 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). >>> 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 [quoted text clipped - 13 lines] > cassette tapes work (though these are breakaway tabs that cannot be > undone, except with a piece of tape). 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. > 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. 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. >> But that simply indicates that >> what's broken isn't the mechanical plunger part of the switch in the [quoted text clipped - 4 lines] > Not necessarily. It depends on whether the switch in the socket is > normally closed with no WP, or normally open with no WP. 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. > One more reason to stick with Compact Flash. 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. >> But that simply indicates that >> what's broken isn't the mechanical plunger part of the switch in the [quoted text clipped - 13 lines] > > One more reason to stick with Compact Flash. 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 snip > 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). There is this <http://www.sandisk.com/pdf/oem/SD_SDIO_specsv1.pdf> snip Signature-- ^^^^^^^^^^ -- Whiskers -- ~~~~~~~~~~ |
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