Quote:
Originally Posted by ghlkal
You're right, scottfab, this would be a better solution. I did replace the pot with 220K worth of resistors. I used one 220K plus three 1K ohm resistors in series. Because they are +- 5%, the 223K stated value was actually 220K. The tach works great now!
Here’s the thread containing Paul’s instructions for fixing the tach (for future reference)
http://www.zr1.net/forum/showthread.php?t=17728
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That's a great procedure. Looks comprehensive. The only thing I'd do different would be to use a trim pot and make it permanent. I would add it's not necessary to use precision resistors only that the value come out right. You can do that even with 5% carbon composite resistors. You do have to measure each on in a box to get one close enough

Or just use a trim pot (10 or 20 turn) and leave it. One would have to probably live with it dangling down far enough to adjust it though. It's one failure I've not experience on mine. (yet)