This web page describes how to disassemble the Meade ETX-70 telescope. It appears that the ETX-70 is different from the other ETX models because none of the existing web pages I could find seemed to match my telescope. The only web page I found with disassembly instructions for the ETX-70 was for the non-computerized model, which is completely different. When I finally figured it out for myself, I made the notes you see below...
This older ETX model is also different from newer models in that part of the electronics is in the base. In the ETX-70EC Owner's Manual you can see how the base must be in a certain orientation at the home position for the wires to the telescope not to be twisted too much. On newer models apparently the base is just a plastic tub on which the telescope and electronics sit.
Flip the scope over and look at the baseplate.Begin by removing the batteries, they can only cause trouble. Two phillips screws are visible, one is hidden beneath a rubber foot. Pry the foot off and stick it back on a little to the side of the screw. Remove the three screws (indicated in red in the photo).
If the electronics or azimuth drive mechanism is all you're interested in, you don't need to go any further than this. If you wish to access the altitude drive mechanism, you need to know the secret! Lay the scope on your work table so it can lay still while you turn the base. You'll need to disengage the azimuth locking lever for this. As you rotate the base, look closely and you'll see three small screw heads appear through a hole in the plastic. You must rotate the base to reveal each screw head in turn. Remove the three screws holding the left fork arm in place. You need only remove the left fork arm.
You'll probably need needle-nose pliers or a magnet to extract the screws. Now unscrew the the big knob on the left fork (the one with the declination scale). Take care not to lose the little clear plastic washer. The left fork arm should now lift off. Unscrew the big knob on the right fork and then you can simply slide the optical tube assembly (OTA) off and set it aside. Five more small screws remove the inner cover on the right fork and the altitude gearing mechanism is exposed.
With the OTA removed, you can examine it's gears and plastic stop to see if anything is awry. While you're here, make sure the little hex screws are tight, they take a 3mm hex wrench. Ignore that small black plastic square on top, that's the base to my Rigel Quik Finder.
Re-assembly is the reverse of the above steps. The only difficult part is dealing with the three small screws you can only access through the hole in the base.