In this instructable I will show the steps needed to remove the existing USB Flash Memory PCB from a Victorinox Securelock "Swiss Army Knife" Memory Stick and replace it with a larger capacity USB memory stick PCB (Here I use a Lexar 2GB Firefly that runs about $25)
I never carried a pocket knife in my entire life until I got the "geek's version" as a Christmas present 3 years ago from a friend. It is a 512MB Victorinox Securelock USB Memory Stick Pocketknife. Since I received it, it is in my pocket everyday and has become indispensable. As time has passed, I have outgrown the 512MB and now I also carry a 2GB stick. To lighten my pocket load I have been thinking about upgrading the Samsung Flash chip on the PCB, but alas the OTi2168 controller chip can only support chips up to 4 gigbits (512MB). I tabled the idea for a while until I was recently given a Lexar 2GB Firefly. Curiosity got the best of me and I popped open the case. The rest, as they say, is an instructable. (or something like that)
Step 1: Tools Needed
Tools you will need
Step 2: Remove the PCB From the Swiss Army Knife Module
Pop the memory stick out of the knife. The PCB (printed circuit board) is held into the case with two tabs that seat into holes on the USB connector. Using two Xacto knives, pry open the center of the case where the small tab is set into the USB connector. Carefully slide out the PCB by holding the top and bottom of the connector.
Step 3: Open the Firefly
The Lexar Firefly case is a snap together plastic case. Using an Xacto knife, pry open the case near the connector until it pops open. Carefully work your way around the rest of the case to pop it open. Remove the LED lens that is clipped to the end of the PCB.
Step 4: Note the Size Difference of the Memory PCBs
Placing the PCBs end to end, you can see the slight size difference. You'll need to reduce the width of the Firefly PCB so that it fits into the knife case. Also, the length will need to be reduced because the USB connector on the Firefly is slightly longer.
Step 5: Filing the PCB to Size
Using a flat file, file the edges of the PCB so that is the same width as the USB connector. You will probably file into the solder connections of the USB connector housing, but that's ok. Check the fit with the knife case, as you want it narrow enough to fit in, but be somewhat tight.
File the end of the module so that it is almost to the via (plated hole) in the center, but leave some of the copper plane running side to side.
Notch the two end corners so that there is room for the posts that are inside the knife case.
Step 6: Check Your Work and the Memory Stick
Doublecheck the edges and plug the stick into a PC to make sure it still functions. If you filed the end too short and removed the copper plane, it may not function anymore.
Step 7: Remove Tabs From Knife Case
Remove the two tabs on the knife case. They will not be used to hold in the Firefly PCB.
Step 8: Insert Firefly PCB
Slide the Firefly PCB into the knife case. It should fit very snug, so that when it is all the way in, it won't come out when you try to pull it out of a USB port. Doublecheck the PCB with a PC once inserted.
Step 9: Modifying the USB Connector to Clear the Knife Post
Since the Firefly USB PCB is longer due to the USB connector, it won't rotate into the knife properly. Instead, it hits the corner post. Filing the corner of the USB connector resolves this and doesn't hurt the integrity of the connector, AS LONG AS you file the corner SMOOTH. Rough or sharp edges could cause damage to the USB port connectors you plug it into. Try to maintain the shape of the plastic piece inside as it tends to "tailfin" from the filing. In other words, it softens and bends up rather than filing off smooth. Running an Xacto along the edge of the plastic piece trims this tailfin off nicely.
Step 10: Finished!
Snap the knife case back onto the knife and you're done. For the old 512MB PCB, I covered it with two layers of 3/4" heatshrink so it is usable and still durable. I flattened the end with a large piece of metal while it was still hot so that it created the "tab". I will probably punch a hole in it to attach it to ???
Step 11: Optional: Updating the Marking
I added a label of the 512MB. I used the instructable hand logo, the size "2GB", and my logo I use for all of my designs "dRu". In case you are wondering, the label was printed on a Brady 600 dpi thermal transfer printer.