Last updated: 7 September 2005

Cleaning Encoders

Subject:	New ETX-90PE with problem...solved
Sent:	Monday, September 5, 2005 20:34:23
From:	Doug Fennell (
here's some problem/resolution info on my new ETX-90PE that I hope
other's will find useful.

Problem - New scope would align using the auto alignment routine, but
would slew 20 or so degrees off to the East when it did it's goto's.

Trouble shooting - Forget about using the plastic setting circle on the
base, instead use the built in digital setting circles. Access them by
holding down the "mode" key for four seconds, then tap the "scroll down"
key twice. Find a terrestrial landmark and slew the scope 360 degrees
and return to your landmark. Check to see if the display reflects 360
degrees of movement. Don't worry if the display is off by a few seconds
or a minute, it's degrees that count. If it's off, it'll be off in 10
degree increments.

Problem and solution - the encoder wheel in the base of the unit has
dirt, lint or in my case the grease used to lube the gears in between
the vanes of the encoder wheel. Each vane represents 10 degrees of
movement, if a vane is plugged up, the display will reflect a 10 degree
discrepancy. Simply remove the three screws in the base of the unit, and
remove the bottom plate (being careful not to break the battery wires)
and clean the goop out of the encoder vanes.

Go back to the Autostar Information page.

Go back to the ETX Home Page.

Copyright ©2005 Michael L. Weasner /
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