The Deliverator – Wannabee

So open minded, my thoughts fell out…

Fix a Dead Internal SD Card on Nokia N800 Internet Tablet

Posted by Deliverator on March 20th, 2007

So, I recently experienced my first hardware related glitch with my N800 Internet Tablet. The internal SD card slot stopped functioning. I tried multiple cards and none of them were being recognized when inserted into the internal slot. The same cards when inserted into the N800’s external SD card slot (the N800 has two SD card slots) work just fine. I did some googling and found a number of other people who had suddenly had their internal slot go dead. Nobody seemed to have any firm idea as to why this was happening, although some suspected the rather flimsy metal clip holding the internal card in place. I tried wedge in a piece of paper to better hold the SD card in place, and also used a jewler’s screwdriver to slightly bend up the metal contact pins, in case one of them had been depressed and was no longer making contact. Neither of these remedies worked for me. The most common suggestion was simply to send it back to Nokia. I have heard some real horror stories about people trying to get their units serviced in anything under a month, so this wasn’t a desirable option for me.

I went back to reading other people’s reports and made a posting on Internet Tablet Talk about the issue. Something mentioned in a few reports suddenly hit me. It was a comment to the effect of “and don’t forget the door has to be in place to register card insertion.” This actually makes a lot of sense for the internal card, which among other things holds a swap file. By providing a sensory mechanism to determine whether the door is on or off, it gives the N800 a chance to flush the page file and prevent possible crashes from sudden SD card removal.

My thought at this point was “ok, so there is some mechanism to detect whether the door is on, but what is that mechanism?” I remembered that the previous Nokia Internet Tablet, the 770, used a magnet on the case to autodetect when the metal slip case was slid over the screen (causing the unit to go into suspend mode). I looked in the n800 and found what seemed to be a magnetic sensor, with a small matching depresion on the inner face of the door with a bit of adhesive still visible, but no magnet. I took a big actuator magnet from a dead hard drive and waved it over the apparent sensor and instantly the SD card registered in the internal slot. As soon as I removed the magnet the SD card disappeared. Bingo!

My hard disk magnet was much to big to fit inside the case, so I tried cutting up a refrigerator magnet, but the resulting magnet was much too weak to trigger the sensor. I finally hit on using a magnetic driver from a cheap pair of earbuds I had sitting on a shelf. These magnets are usually quite strong and just waving the earbud itself lightly over the sensor was enough to trip it. The magnet I extracted was plenty powerful, but still to big to fit comfortably in the little rectangular depression on the inside of the case. I used some metal cutters to shear off a small shard, inserted it in the depression and then mixed up a some epoxy to ensure it stayed there for good. Problem solved.

I’ve only owned my N800 for a few months and have definitely been babying it. Given the number of complaints I have already seen about this issue, I suspect this will only become a bigger issue as time goes by. The poor quality adhesive attachment method used by Nokia to secure their magnet does not speak well of their hardware design.