Meade ETX-70AT Repair Manual page 10

27) Slide the objective lens all the way down the OTA. You might need to wiggle
the lens a bit to get the shaft to come out the back of the eyepiece holder
assembly.
28) Here we have a couple of options. You can use another #6 washer on the
outside of the assembly to remove the slope in the focuser. I found that the #6
was too thin and wanted a thicker washer. I found a 1/8î X 1 fender washer
was the perfect thickness but was a bit too large. I cut one side down with
a pair of side cutters and sanded it smooth. This also provides another
layer of protection from the shaft being shoved out again. Test fit the
outside washer with the knob attached before you epoxy it in place. When
you are ready to glue, just slide the lens back a little bit to pull the shaft
inside the OTA. Once dried slide the lens back, guide the shaft through
the hole and attach the focusing knob. Set the OTA aside.
29) CLEAN CLEAN CLEAN!! Next carefully remove all the old grease from
the scope and support braces. Use the mineral spirits and cotton balls to
clean them up nice, then dry it completely
30) Sand both sides of the white nylon clutch bushing. Make sure it is free from
grease. Apply a small amount of lithium grease to the teeth of the OTA gear
then slide it onto the right OTA shaft followed by the clutch plate and black
plastic bushing. The bushing has a guide notch and only fits in one way.
Apply a small amount of grease to the outside of the bushing. Only the
areas pointed to in red above should have any grease on them, this is very
important if you want your scope to track accurately.
31) Apply a small amount of grease to the worm gear inside the right support
brace, and then replace the cover plate and 5 screws.
32) Remove the bushing on the left riser brace, clean it, and reapply new
lithium grease. Make note of the 3 plastic pins that match up to the holes
on the left side of the OTA.
33) Replace the OTA into the right fork, loosely threading on the right
large plastic bolt to hold the OTA in place. Take note to align the
left side brace properly to the OTA. The pins (circled in red) on the
left bushing must line up with the holes on the OTA if the stops are
going to work properly. Rotate the left brace into its original
position and replace the left locking bolt snugly. Snug up the right
nut, and then replace the 3 large screws that hold the left brace in
place from below the scope base. Set upper assembly aside.
34) Pick up the lower base, remove the 3 screws holding the large gear and
clutch plate in place.
35) Sand both sides of the clutch plate and degrease the drive gear.
Reassemble and apply grease only to the outside teeth.
36) Apply a small amount of grease to the worm gear under the base.
Apply a small amount of grease to the metal shaft, and then replace one
of the nylon bushings.
37) Carefully slide the lower base into the upper assembly. Be careful to
make sure the lower drive assembly is all the way back. It is spring
loaded to keep it engaged to the large gear. I angled the base slightly
towards the drive assembly and wiggled the base down without any
force. It might take a couple tries, but DON'T FORCE IT, it will
break, and you will be in real trouble. Once in place insert the lower
nylon bushing, it will wiggle into place.
38) To reassemble, replace the bottom black base, gently working it
around a little until the gears settle onto the drive worm-gear teeth.
Then replace the white castle nut under the scope and insert the clutch assembly as show above.
You will notice the bottom round "nut" sits inside the 4 raised ears. Tighten the white castle nut up
hand tight, firm. Don't over torque it, just make sure it doesn't back out. Then reassemble the
clutch in reverse order. Before you reattach the lever, adjust the clutch engagement point by