Meade LXD-650 Declination Runaway repair - Philipp Salzgeber photography

The last time I wanted to do some deep-sky astrophotography, I ran into an issue with our astronomy club’s LXD-650 mount – immediately after switching it on the declination motor started to run at high speed.

After some research on the internet I was able to resolve the issue, by tweaking the setting on the potentiometer responsible for the declination encoder LED light.

Some notes to anyone interested in doing this:

To remove the manual declination and rectascension knobs you have to lift the rubber grip around the knob to be able to loosen it from the axis
Imperial Allen keys are necessary (I had some in the form of extra bits for my Leatherman wave)
you only need to loosen the screws in the corner of the plates on the mounts housing
take care to note the orientation of the connectors before unplugging them, as some can be used in either orientation

The blue squares with the red axis are the potentiometers responsible for the pulse rate of the encoders.

This image shows the relative orientation of the front- and back PCB .

The potentiometers can alos be accessed by only taking off the back cover, and unscrewing the small motor board from the motor.

Here are some links I found helpful while trying to resolve the issue:

http://www.b82maidbronn.de/lx200.htm
http://www.cloudynights.com/topic/447376-ugh-dreaded-%E2%80%9Cmeade%E2%80%9D-boot-error-haunts-my-lx200/page-2#entry5810815
http://www.bbcl03736.pwp.blueyonder.co.uk/LX200%20Faults.htm