As my friend gmjhowe recently pointed out, Mini-DV and pretty much all other tape formats are on the edge of being entirely replaced by internal and card memory systems. However, I figure a few people may run across a similar situation with a broken tape, and thought documenting this process may prove valuable if you have an old tape break that is the only remaining copy of a wedding, graduation, or other important event you want to save.
This process is also pretty much the same for other kinds of tapes like VHS and VHS-C, D8, etc. The only real difference is the bigger tapes won't require a precision (aka jeweler's) screwdriver. In this case, my employer had some footage mailed to us, and the tape was smashed in the mail. With the protective casing busted, the machine would just spit it back out and not engage the tape head.
What you need:
1.) small screwdriver
2.) original busted tape
3.) new donor tape
4.) pen flashlight
Step 1: Remove Reel From Casing
Basically what we're doing is taking the reel from the broken case and replacing the new reel in our donor casing. Most Mini DV tapes have four tiny screws located on the underside of the casing located near the four corners. Carefully remove these four screws without letting the tape fall apart and exposing the insides.
On this particular case, the tape had no screws to remove and was either tabbed or glued together. I carefully broke the casing apart taking special care not to cause damage to the tape by way of wrinkling, crinking, stretching, poking, handling or otherwise touching the reel. At this point in the second picture I was able to pull out the left part of the reel. With half of the tape removed, getting to the other half was quite a bit easier. When the reel is entirely removed, I suggest winding all the tape to the left reel (thus fully rewinding the tape).
Step 2: Move Reel to the Donor Tape
Removing the same four tiny screws on the back side, carefully place your tape on the work area and remove the top cover to expose the reel on your donor tape. There are a few pieces that are very difficult to correctly place back in position, so take care to remove the donor reel from the tape casing without disturbing these. Add a small amount of extra slack and place your salvaged tape in the new case. Once it's properly in place, wind out the slack by hand. Place the cover back on top and screw the casing back in place.
Step 3: Copy Tape to Permanent Media
I highly suggest only using your repaired tape one time, and only to copy it to something more lasting. For me, the worry was having small overlooked parts of the tape slip into my video deck and be pretty much stuck there. Also, if the tape has suffered damage, you may only have one chance to copy it. Besides risking loss of the footage forever by not immediately copying it, damaged tape is also hard on the equipment running it. Avoid using the tape in costly cameras if at all possible.
In this case, I captured the contents of the tape by playing it start to finish, one time, into my work computer. With the video encoded, I was free to do whatever I needed to with the footage. I checked the captured footage to make sure it included everything I needed, and then gathered everything from both tapes and discarded them. I figured that would keep me from ever accidently using them again. Short and sweet, your work is done. This has been instructable number eight, grab a donut and some orange drink on your way out. Ratings and comments are also highly encouraged.