tacho capacitor

[street]

My tacho has always been bouncy, luminition installed without wiring changed, now all of a sudden tacho works on start up, runs say 10 seconds and dies. start up and the same every time. reading posts i suspect it is capacitor.

I have attached photos of my tacho, later RVI type? which one do I need to change, and what grade, .22uf?

thanks

IMG_0010.pdf

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[Andy8421]

It looks like you have a later RVI type. Have a look at:

https://www.mgexp.com/forum/mgb-and-gt-forum.1/tachometer-fix-1970-mgb-smiths-rvi-1433-00.3977387/

The picture seems to match your unit.

If this is the case, then the cap in question should be bigger than .22uF, the circuit diagrams suggest somewhere between 2 and 2.5uF.