[Half-Inch Stud]

Check all my 4-pin Modules and a couple 7-pin modules. They all work: Triggering on "Make". All showed Dwell Expansion about 7* at 600 rpm to 22-24* by 2500 rpm. Motorola M3334 Packaged IC evident in 1-module with loose lid.

A 7 pin module goes 7* - 22* - 17* which seems strange.

Observation is how the Module Grounds through the mount screws, which is very important.
1 screw boss may show a Steel cap welded to a steel midplate. Best gronud.

Brass sleeves pressed-in and they touch the Aluminum Base: good ground.

Brass sleeves that "rivet" at both ende: LOOSE as a goose, a definite failure mode for Grounding even when the 2 screws tightened.

Steel roll-pin sleeves; possibly poor ground. Both 7-pin modules have such.

Voltages present at Reluctor terminals:
1.30-1.36V except the GM 990 shows 1.86V. White being 0.01Volt above Green (no reluctor connected).
7-pin modules show 1.0Volt for white 0 Volt for Green.