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I have to correct my earlier post. The values of the resistors I purchased were not 200 and 200k ohms but 220 and 220k ohms. To be exact, the descriptions for these resistors are 220 ohm 2% 1/2w and 220k ohm 2% 1/2w.

Be that as it may, there is a different outcome if you use the higher value resistors. With the 220 ohm resistor soldered in place, the tach needle did not register any RPMs; but when I switched to the 220k ohm resistor, the needle registered 900 RPMs. At idle, 900 seems a bit high and I suspect that if I were to use 200k ohm resistors the readings would drop down a bit and be more accurate. I have an old Dixco somewhere and will do a comparison.

Overall, to do this repair was not very difficult and took maybe 5 minutes to complete. Any novice with limited or very little soldering experience could easily accomplish this task. Good luck!!

Now, the only gauge not working is the oil pressure. I'll leave that to another thread.
 

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Update: Yesterday, I visited another electronics parts store and was able to purchase more resisters...200k and 180k ohm which were a quarter each. I also discussed the meaning of different watt ratings with the sales person. Basically, the 1/2w identifies how much current the resister is able to tolerate. (I ask someone or anyone with more knowledge in this area to correct me on this point.)

Upon installing both of these valued resistors, in-turn, the 180k ohm resistor gave me the best results for a particular tach. By this I mean, it appears to me that each tach will respond differently to the value of the installed resistor. One of my tachs registered 700 RPMs with a 180k ohm resistor while the other went down to 550 RPMs. Bottom line is once you get the hang of soldering, try different values of resistors to "tune" your tach. Good luck!
 

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I saw something about using a variable device or resistor but decided to stick with what little know-how I possessed and simply use resistors. Besides, the cost of each resistor made swapping out resistors an easy choice.
 

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Keeping fingers crossed...doing the filter repair has worked. At idle in neutral, idle reading is 700-750 RPMs; in gear, idle drops to 550-600.
 
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