Bulk Erasing Cassette Media

Ugh... this tape drive is going to be the death of me! Now that I have a small supply of Maxell tapes for my TEAC MT-2ST/N50 cassette drive (thanks Don!!!), I've run into the next problem. All the tapes are reported as "content unknown", and claim to be 60 MB (the drive claims to do 150 or 160 depending on which info you pay attention to). Neither of those are too big of a surprise as the tapes are used, and logically have data that Retrospect on the Mac can't understand, and may very well have been written to last with an earlier version of the drive (different models support different MB's, and from what I can tell, the tapes are all interchangable for writing at max MB, and upwards readable so you can read a lower MB tape on a higher MB drive) However, all the tapes ALSO report that they are locked. Regardless of how I set the write protect slide, the tape is still seen as locked. Which means I can't erase or write to the tapes. I opened the drive, and the write protect sense switch appears to be physically functional. I have not yet broken down the drive enough to see if it is electronically functional (although about the best I can do is test for switch continuity in the open and closed positions). I'm wondering, is it possible they are seen as locked because of the data on them? Is there a way to software lock the tapes? Or maybe the locked is a side effect of having been last written at a lower MB (some kind of a safety to keep you from screwing up the data with a higher MB drive). If so, is it safe to bulk erase the tapes to wipe the data, or will I destroy some kind of a control track as well and render the tape useless? I know some kinds of media should not be bulk erased for just that reason. I would just give it a go, but since I only have 10 tapes, and these have proven a bit tough to locate, I don't want to destroy a tape without at least consulting the resident group of experts. TIA -chris <http://www.mythtech.net>