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On 10 Feb 2004 at 12:38, Mike Wodkowski wrote: > This is a 72 FI squareback. The generator is a rebuilt bosch. > > Brushes are fine. Commutator shows some slight wear lines that may indicate > a short. But not as severe as other times. > > When I disconnect DF and D+ I get a reading of 1V when I connect VOM red > lead to D+ and black lead to gnd. This is normal. (The reading is positive, +1V, isn't it?) > Then, with VOM still connected, when I ground df I get a voltage DROP to > almost 0. I checked this three times to be sure and this is the case. Assuming the wires are all still disconnected, this indicates a problem inside the generator. This is your smoking gun. Concentrate on the generator. Did you try pushing in on each brush while doing this? > The disconnected D+, with respect to ground, reads 30 ohms > > The disconnected DF, with respect to ground, reads infinity. If these are measurements taken on the WIRES, just ignore them. They won't mean anything to anyone and just muddy the waters. Don't even measure them. They aren't helpful. > Measuring across DF to D+ posts on the generator, I show 3 ohms. Sounds close, but a little low. I expected to get 4 ohms, but this could just be the accuracy of the meter (or of my memory.) Or it could be that the field coil (that's what is being measured here) has a bunch of shorted turns, which probably means that it overheated for some reason. When you install the generators, are you making sure the ventilation hole is pointing straight down? There's a scribed line on the top that should be aligned with the dot in the middle of the mounting strap. Is there any chance that they gave you a non-type 3 housing that didn't even have a cooling hole? I'm just trying to imagine what's causing all of these problems. When you attach the D+ and DF wires are they the ONLY wires attached to those 2 posts? There are other wires that originally went there, but I recommend that you leave all of them off from now on. One of them might be shorting to ground and causing problems. If you wanted to send me the generator I would be happy to look at it, but I realize that's not much help from this far away. You might just be better off exercising your Bosch warrantee, or has it expired? If you like, I could send you a good generator first. -- Jim Adney jadney@vwtype3.org Madison, WI 53711-3054 USA ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org