Guts of a tach

mikebc

Petty Officer 2nd Class
Joined
Apr 10, 2005
Messages
111
Hey everyone,<br /> <br /> My tach quit a couple of weeks ago after working on and off for a year. I've checked all the voltages and grounds to the tach, all are good. I am about to try and take the tach itself apart and test the internals out. Does anyone have a diagram for the internals of a tach? I realize they are all slightly different, but the basic principals have to be the same. Just trying to save $50 on a new tach, plus I enjoy fixing stuff, or breaking it beyond repair, either way! I have a digital multi meter and know how to use it very well. The tach is original and it's on a '87 3.0 mercruiser craft. Thanks for any input!
 

trog100

Senior Chief Petty Officer
Joined
Dec 1, 2004
Messages
751
Re: Guts of a tach

never actually pulled one apart.. but i think u are right about the basic pricples being the same.. they kinda read the pulses from the points i would guess.. the magetic bearing arrangement that moves the needle is probably the bit most likely to fail..<br /><br />i dont hold out much hope as regards fixing it.. but no harm in trying.. u might learn something along the way.. he he<br /><br />see if this place throws up any help..<br /><br /> http://www.howstuffworks.com/ <br /><br />trog100
 

mikebc

Petty Officer 2nd Class
Joined
Apr 10, 2005
Messages
111
Re: Guts of a tach

I'll give it a try and post pics of my findings. My best guess is that some kind of winding wire is broken or rusty.
 

mikebc

Petty Officer 2nd Class
Joined
Apr 10, 2005
Messages
111
Re: Guts of a tach

No go,<br /> It's a sealed unit, the face does not come off. Off to the parts store I go. That hole in the water sure is.....
 
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