Alan,
Yes it has a short in Fixed 1 output. I just sent my bad tiu to an ASC MTH tech (Ray Manley) I've used before and really like. I just took a chance and tried my replacement Dash-9. It started doing the same thing the first one did. The engine noise was on, then cut out for about 10 feet, then came back on. I immediately shut down my Z4000. I think I shut it off fast enough so there was no damage. I believe there is a bad batch of boards in these Dash 9's. I'll send the locomotive to Ray and let him verify my suspicions.
Thanks,
Don