MDM Trouble Report for 2002 Nov 12

Telescope: 1.3m
Observer(s): Burke (OSU)
Instrument: 8K

Problem(s) Encountered:
Approximately, 2:15 am local time, in the middle of an exposure, telescope began failing to respond to declination movements from autoguider.  Telescope also did not respond to declination guide speed movements from paddle in control room, telescope control in dome, and hand paddle on telescope.  Set speed and slew work fine in all directions.  When problem first began, the declination guide speed moved about 2-3  either direction and then would not move further in either direction.  Only after a set speed movement would the declination again be able to move the 2-3  and then halt again.
To try and rule out a software problem, I stowed the telescope at zenith, and did a complete shutdown (followed lightning shutdown procedure).  Computers, instrument, and tcs all came back fine after powerup.  Turned on telescope drives and still had difficulties with declination guide speed movements.  Although slightly different in that North guide speed movements work, except they seem jerky on the TCS monitor (moving 2-3  followed by a pause then another 2-3  and pause...).  Watching the declination drive (or motor looking object near the dec pivot point on telescope), the spining axle also shows jerky motion when using North guide speed.  The South guide speed as before moves 2-3  and then halts, and will not respond until larger set motion is used.  This is also verified by watching the dec. drive axis.  It spins a bit and then halts motion.

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Submitted on 2002 Nov 12 [5:15:41]