After two years, I finally ordered the pilot mount replacement parts I lost and scalified my MoPac SD70 over the weekend. Ran fine on Sunday, blew the dust off with pressure can duster, took some pictures.
Went to noodle around with it today and blammo! The dreaded 6 flashes of death of the cab lights. The front truck moved, the rear truck (and that's where the speed sensor is...) didn't.
Arrgh... After a while I remembered blowing off the dust and some ballast getting kicked up.
Closer examination revealed the rear truck wheels wheels did move a little. (Very little..) Further examination revealed the gears had picked up some pieces of ballast. Pulled off the sideframe and could see several chunks of ballast decorating the gears.
Fortunately, the rear truck's motor is under the removable radiator, so easily it's possible turn the flywheel until the gears bound up, back off a little and remove the offending chunk. Once all were all were removed the wheels turned freely. I gave the area a blast with the duster (this time, not on the layout...) to get a couple of other chunks lying around nearby.
Put it all back together and everything runs fine once again.
Whew...
Rusty