ETX mount issues

dew · Post by **dew** » Wed Nov 05, 2003 1:50 pm

hi all,

i am considering trying to take off my ETX-125 OTA off its fork mount and mount it on to a manfrotto 410.. would lighten up my load considerably, especially with a lighter tripod..
only thing is, i dont know how.. was looking at it just now and there are alot of screws in hard to reach places. alot of corners where my screwdriver cant reach. i know there are alot of DIY people here, could some of you provide advice?

on another matter, is there any way to change/replace/modify the ETX star diagonal and focusing mechanism?

and yet another matter, i need to open up my ETX mounts drives. everytime i pick up my ETX i hear a clickity sound from within the mount. like a bead in a box sort of sound.. think there might be some small loose part running around inside.. and if possible would also like to try to fine tune the motors. get alot of laggy movement when i use the controller..

yup thanks for reading everyone, would appreciate any advice on the matter(s)

eu-wen

Gary · Post by **Gary** » Wed Nov 05, 2003 2:36 pm

Maybe you can try searching this site if you haven't done so :

http://www.weasner.com/etx/menu.html

Post by **acc** » Wed Nov 05, 2003 10:03 pm

I had some experience performing surgery on my ex-ETX90EC. To remove the RA base, peel off the three rubber feet on the drive base to review screws under each of them. Remove these. Then carefully pop off the drive base, taking care not to impose strain on the fragile wires that connect the PCB to the battery holder on the base. I suspect the rattling sound u hear is caused by a screw which have fallen off either the motor or worm gear mounting bracket of the RA drive.

I believe ur ETX125 is one of the newer models that have aluminimum instead of plastic fork arms. Don't have experience with these new models, so can't help you with the removal of the OTA.

Post by **Airconvent** » Thu Nov 06, 2003 1:56 am

acc wrote:I had some experience performing surgery on my ex-ETX90EC. To remove the RA base, peel off the three rubber feet on the drive base to review screws under each of them. Remove these. Then carefully pop off the drive base, taking care not to impose strain on the fragile wires that connect the PCB to the battery holder on the base. I suspect the rattling sound u hear is caused by a screw which have fallen off either the motor or worm gear mounting bracket of the RA drive.

I believe ur ETX125 is one of the newer models that have aluminimum instead of plastic fork arms. Don't have experience with these new models, so can't help you here.

chee chien has given you a good idea on what to check for the sound you heard. for removal of the OTA, as below:

What you need to do is using an allen key (imperial size!), remove the 3 screws behind the OTA where your visual back is. Remove the focusser knob as well. Once done, the OTA will slide off in front out of the plastic holder. Next, with gentle care, remove the plastic holder from the fork mount. Without the OTA in the way, all it needs is a little pushing but TAKE GREAT CARE WHEN DOING THIS. You can easily break something and its not replaceable! Then, , reattach the plastic backing onto the OTA.

caution #2 : while removing the plastic back mount, do so carefully as the bearings and sleeves will drop off from the fork mount as they are no longer held in place. Make a note on the sequence in which they are inserted, so that you can replace it when required. It will also be a good time to clean up fork mount bearings of grease as they cause slippage on the clutch.

reference sites (they have pics!) :

www.weasner.com
www.atozastro.com

rich

Post by nF » Thu Nov 06, 2003 2:16 am

hehe Richard the ETX club expert =P

Post by **Airconvent** » Thu Nov 06, 2003 2:28 am

mmm...missed out some vital info in my earlier post, so have amended it..heh heh

rich

dew · Post by **dew** » Thu Nov 06, 2003 11:37 am

Remove these. Then carefully pop off the drive base, taking care not to impose strain on the fragile wires that connect the PCB to the battery holder on the base. I suspect the rattling sound u hear is caused by a screw which have fallen off either the motor or worm gear mounting bracket of the RA drive.

yup thanks cc.. just opened it up, you were right.. a loose screw inside.. also the gears had a hell lot of green grease on them.. like just splotched on top of all of them.. is this normal and would it affect performance?

What you need to do is using an allen key (imperial size!), remove the 3 screws behind the OTA where your visual back is. Remove the focusser knob as well. Once done, the OTA will slide off in front out of the plastic holder. Next, with gentle care, remove the plastic holder from the fork mount. Without the OTA in the way, all it needs is a little pushing but TAKE GREAT CARE WHEN DOING THIS. You can easily break something and its not replaceable! Then, , reattach the plastic backing onto the OTA.

and thanks for the guidelines rich.. sounds quite complicated.. and risky.. think ill just try it once i totally understand the procedure..
thanks!

eu-wen

Post by **acc** » Thu Nov 06, 2003 12:29 pm

yup thanks cc.. just opened it up, you were right.. a loose screw inside.. also the gears had a hell lot of green grease on them.. like just splotched on top of all of them.. is this normal and would it affect performance?

That is Meade's Grease Heaven for you!

Remove all these excess grease leaving only a thin layer on the gears. While you are at it, locate and remove all grease and dirt on the optical encoder wheel which is a small white plastic disc with radial spokes and located near the motor. A dirty encoder wheel can cause the much dreaded Motor Unit Failure.

Always wonder how Meade can ship such a badly assembled scope... But it performs fine once the problems are sorted out and the ETX has excellent optics too.

dew · Post by **dew** » Fri Nov 07, 2003 1:12 pm

ok, took some pictures of the inside of my ETX for the benefit of anyone wondering what ever was in there but didnt want to open it up..
anyway, this is after i cleaned up some of the grease.. the grease is the green gooish stuff you see on the gears.. there was at least twice as much, if not more grease on it before i cleaned it..
cc could you point out the optical encoder? i dont know which one it is.. thanks.

eu-wen

Post by **weixing** » Fri Nov 07, 2003 2:21 pm

Hi,
Although I'm not familar with ETX-Mount, but in my experience in robotics, I can help by roughly guess which are the encoder. My best guess is the black circular "object" is the coupling gear with the encoder built-in. The red and black wire should be the power for the encoder and the blue and yellow should be the encoder output.

Hope my guess are correct...