Rev counter rebuilding ...

[Xte]

Hi,

After discovering that my revcounter indicates 3000rpm instead of 1000rpm, I've decided to rebuild my BJ8 electronic revcounter. I've read that most of the problem is due to a capacitor that we have to change... picture below :



But I find an other component closed to this capacitor in a very bad condition as you could see in these pictures ... Do you know what type of component is it and his value, to be able to change it ... thank you for your help ...

I'm really surprised ...it's the first time I do electronic restoration in a classic car ... ;-)

 

[RAC68]

Hi Xte,

It is not uncommon to have that component deteriorated to the point that the tachometer will register high. Although I had replaced that unit in my tach a while back, I do not remember, off hand, its identification. However, take a look at this site for the answer (https://www.hazelden.ca/austinhealey/RebuildingBJ8Tach/).

Hope this helps,
Ray (64BJ8P1)

 

[Bob_Spidell]

Looks like a tantalum capacitor. Photo shows 0.25uF cap, schematic doesn't (probably used instead of the 0.47uF in the schematic). According to the schematic, there are only two other caps, one is a 0.1uF and one is a 100uF; if you can identify the remaining cap you can use elimination to deduce which one the bad one is.