What you say above is certainly true for tape systems where the same head is used for reading and writing, and most small tape drives fall into this category. But most 7-track and 9-track drives have separate read and write heads, and these are often out of skew with each other. Because the read and write heads are often part of the same assembly, the necessary deskewing can be a combination of both physical adjustment (to get the read head correctly aligned) and electronic timing adjustment (to get the write pulses aligned on tape relative to the read head.) There may be some drives where the write head is physically adjusted and the read timings are electronically adjusted, but this makes the entire procedure much more difficult - what good does a master skew tape do you in doing mechanical alignment of the write heads??? :-) For most drives with electronic deskewing (and the Kennedy 9100 and successors certainly fall in this category) when you get a replacement head it comes with a set of "starting" electronic deskewing settings. I'll gladly fax you the section of a Kennedy maintenance manual that details the procedure, if you're interested. Absolutely. Barring physical damage (a good drop onto concrete from a few feet is enough to whack other things out of alignment) I'd look for other causes first. The NRZI data path is different than the PE data path, for one thing. -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology WWW: http://www.trailing-edge.com/ 7328 Bradley Blvd Voice: 301-767-5917 Bethesda, MD, USA 20817 Fax: 301-767-5927