Replacing TinyTach battery

[Bodach na mara]

I got a TinyTach about five years ago. It has an internal battery which is supposed to last five years, and as expected it is not working this year. Why it could not have failed when I tested the engine in March I don't know!

Has anyone tried cutting one of these things open to replace the battery? As they are basically a potted-up cycle computer with some signal processing to get them to accept a signal from a piezo sensor on an injector line, I expect that the battery is just a button cell and should be easy to source. The problem is where and how to attack the sealed casing.

 

[srp]

Has anyone tried cutting one of these things open to replace the battery?

Looked quite promising at this stage, it is potted in a rubbery compound. However, it proved impossible, even taking a lot of care and spending around 2.5hrs on it. The details elude me now as it was some time ago, but if you're hoping to pop a new button cell in then you'll be disappointed.
I must admit that my track record with Tinytachs is not good - the first lasted about a month, the second even less, and by the time I got the third replacement I'd lost the will to live.

 

[VicS]

Chuck it . get a new one. the new ones don't have an internal battery. They have not had batteries in them for about 4½ years

 

[AngusMcDoon]

Chuck it . get a new one. the new ones don't have an internal battery. They have not had batteries in them for about 4½ years

Or make your own YAPP-o-tach for a fiver ...

http://www.ybw.com/forums/showthread.php?t=277354

 

[Bodach na mara]

Thanks all. With my record of personal injury while using sharp things, I think the bin-it solution is best. The YAPP-o-tach sounds fun though.

 

[yellowspinnaker]

I use one of these. Never needs batteries and can be used for all sorts of things.

Diesel engines, petrol engines, washing machine spin cycles, outboards, etc etc. All without needing to attach wires, expose the innards.

Great fun at quizzes, too. Vary few people are going to know what it is...

http://www.treysit.com/6.html