As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE OVERHAULED MAGNETO WAS PURCHASED. UPON INSTALLATION OF THE MAGNETO, THE TACHOMETER DID NOT WORK. FURTHER TROUBLESHOOTING REVEALED THAT THE TACHOMETER CONTACT ASSEMBLY HAD NO CONTINUITY ACROSS THE POINTS. THE CONTACT ASSEMBLY WAS REPLACED WITH A NEW CONTACT ASSEMBLY.