In my bag of tricks I have two tachs. One, an old Dixon tach . Kinda looks like something Bones would have pointed at somebody on Star Trek- to do what ever Bones did to people who needed pointing at. Readings are consistent , but not finite enough. The other is a ESI test 328 Ez tach. This has been a nice tach over the last few years. Last fall, it had gotten erratic at times. I had written the manufacture rep in Wisconsin, and they were nice enough to solder something and mail it back at no charge. It has worked as planned for a while, but is getting buggy again. It seems more so on some of the real new stuff. Any correlation? Or recommendations for a different unit? I could see the merits of this fine tool, TA 100.

Here is a link that might be useful: ta100