quote:Originally posted by Bosswrench:
You guys are assuming the stock rheostat is working as it should. It may well not be; quite a few have failed utterly and it seems reasonable that others are not fully functional. Inside the Rheostat is a curved wound-wire potentiometer and a thin copper strip that has a ball bearing running on it to make contact without wear. The key issue is, ALL electrical power goes through a 1/2" long hair-fine wire that often breaks from old age.
And you don't even need to disassemble the thing like I did. On the back of the stock rheostat are a pair of stubs that if bridged, will parallel the feed thru that hair-wire inside and restore full function. With a BIG soldering iron, I soldered a 12-ga. bridge-wire across those visible stubs and my non-functional rheostat now works fine. If a VOM shows less than 5 ohms- or open- thru your rheostat (or maybe even if it does show correct resistance) I suggest bridging those contacts before trying other add-ons.
Boss,
I took my rheostat completely apart and cleaned it. The issue is that it is not linear and repeatable enough in my opinion to do what is required to operate the Protizmo unit. Rotating the knob connected to my Fluke 87III VOM showed the resistance to bounce around rather than be a smooth transition from 5.X to 1.X Ohms. Now that said, It worked just fine to dimm the incandescent bulbs.
Steve