MDM Trouble Report for 2014 Dec 10

Telescope: 2.4m
Observer(s): Thorstensen, Alper, Colon (Dartmouth)
Instrument: modspec + echelle CCD

Problem(s) Encountered:
I followed a target far to the west and around 2:30, near an
HA of 5:30, the tracking stopped.  I figured the telescope had
hit a limit, though I had thought it would go to 6h west at this
dec (+26 degrees).

I slewed out of the limit and when I got to the next position
the telescope never settled.  The HA was not moving, and I
couldn't get it to move; the telescope responded to the paddle,
but not to set rate in the E-W direction.  

After turning the tracking on and off, turning the drives on 
and off, and cycling the power on the black box several
times, I took the dangerous step of restarting the TCS computer.
I didn't power it down, but rather hit the reset button, and it
did come up, but had lost pointing entirely.  This didn't 
cure the problem.

Finally I went out and looked at the RA drive assembly.  The 
tracking motor was spinning but the small toothed drive belt 
that connects it to the mechanism was slipping. I had Erek 
flip the motor on and off, and it started and stopped as 
expected but the drive belt was still slipping.  By exerting
gentle pressure on the belt I could get it to move, but it would
slip as soon as it came back to the same bad spot on the belt.

We looked around for replacement belts, but couldn't find them
(perhaps this is just as well).  With the problem diagnosed, and
nothing to do about it, we shut down.

We put the telescope back to the zenith using the tilt meters,
and reset the coordinates, but it's not accurate in RA since
we had no fine motion.  The rotator position was also lost; 
we set that to zero by eyeballing the tape (is there a
more accurate fiducial somewhere?)  We also put the dome back
on the contacts and set to 320.  


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Submitted on 2014 Dec 11 [3:23:28]