Lee, will of course, answer for himself ---- however, if you zoom in on the picture of the case (backside) you can read SKYBORN ---- so it is one of the new ones, not made personally by Tony.

I too have one, without the button problem so my guess is that it was a problem in assembly not of design. As for the on off switch, I happen to like the slide type switch as you do not have to "hang on" to anything but the tach while taking a reading. I would class this as "personal preference" ------in my case, I used the original Heath Kit Thumb Tach (same on/off set up) for years so I am used to the requirement of switching off.

Lee, many thanks for the "review" and pictures, saves me from disassembling mine.