Quote:
Originally Posted by ndutton
There are only two possibilities for your test result: - Defective points
- Testing technique
Be certain the pointed test probes are making good contact with the conducting metals by rotating them or "drilling" them through whatever might be on the surface into the metal. |
First of all, I am grateful to everybody that replied so far, confirming that I am not completely crazy and overlooked something really stupid! When this happened on two completely unrelated sets of points, one having been used for years and the other brand new, I started to doubt my sanity
To your two (ehm) points
: what would be a failure mode of two touching metal surfaces? I suppose there could be a layer of grease on the new ones, as Joe suggested, and oxidation on the old ones? This is why I sanded the old ones, without success. I did nothing to the new ones. Perhaps I should invest in a points file?
Testing: sure, that is always possible but it seems pretty unlikely. I scraped the metal surface pretty good, and I had immediate contact on one side but nothing on the other. But you are right, stuff happens. Now that I think of it, one way to make absolutely sure is to measure resistance between two locations on the ground side, confirm that it is ~ zero there, keep one of them where it is without moving, move the other one to the 'hot' side. If I get ~zero, the problem was with my measuring technique. If I do NOT get that, move the first point to the 'hot' side. If now get ~zero, I know that there really IS no conductivity across the points.
I am 99.9% sure that it is not measuring technique. Have done this MANY times....