I have a NYC SD80MAC (6-18297) that is new to me. It was on a shelf but I was told it ran at some point. I decided to do some routine maintenance and upgrade the smoke unit, so I removed the shell. I soon discovered a few chaff wires associated with the rear pick-up rollers. I repaired the wires before applying power and running it. Once on the track, the engine responded to all the TMCC commands. Both engines turned in unison. However, when I lifted the engine slightly off the track, I noticed that I was only getting power from the front pick-ups. If the front of the engine was slightly raised, their was no power to the engine. Since, I worked on the rear pick-ups, I naturally rechecked my work. The rear pick-ups seem to be wired correctly. I checked continuity from the pick-up roller to the mini Molex connector plugged in to the motherboard (J6) and both the ground (black wire) and hot (red wire) showed continuity.(I touched a wheel to check the continuity of the black wire) Further, I applied 14 VAC to the pick-up and wheel and saw that voltage at the Molex connector. (But...the engine did not respond once I put the Molex connector back into the motherboard. It would appear to me, I have voltage up to the motherboard but it is not getting distributed. Is it possible that their is a problem with the motherboard? What other troubleshooting techniques should I employ to narrow this problem down and rule out my repair as a culprit.
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