CG5 declination motor just stopped working!
Posted 08 July 2012 - 11:33 AM
Last night I was at a star party for the ALCon2012 convention. My second star party this week. My mount worked perfectly fine at the Wednesday night star party and was working fine the first half of last night's star party.
At one point, someone asked if I could slew to the moon since it had finally just cleared the trees on the horizon. I punched the command into my scope and off it went. Except it was widely off track. The RA axis was moving as it should, but the DEC axis not moving at all. I tried slewing to a different object, and the same thing happened. RA motor would slew and track but the DEC motor wouldn't move a millimeter. After the scope would come to a stop after slewing in the RA, it would just sit there. The hand controller still had the spinning thing in the display indicating that it was still trying to slew even though it wasn't moving anymore.
I turned off my mount and moved back to the index marks. Started the mount back up and tried to perform a two-star alignment. No go. The RA would move but not the DEC. I unplugged and replugged in the DEC cable from both ends and tried again. No go. I repeated this cycle a couple more times to no avail.
Eventually, I grew tired of messing with it and decided to just start hand-pointing my scope to targets and letting the RA axis continue its tracking. It made for a VERY slow rest of the night at the star party. Star hopping with an inoperable CG5 mount is tedious and slow!
So, anyone have any ideas what may be causing my issue? Is my DEC motor burned out? Is there loose connections in the DEC port? Bad DEC cable? I won't have any time to pull it apart and start looking at it for a few days. So I'm hoping to get some ideas from y'all in the meantime. Thanks!
Posted 08 July 2012 - 11:42 AM
Posted 08 July 2012 - 12:02 PM
And by "not move," do you mean you can't hear the motor running at all, or just that the scope is not moving?
Posted 08 July 2012 - 12:08 PM
You should check the connections of the Dec motor first. Make sure that the Dec cable is full seated in the sockets at both ends. You should also look into the sockets and insure that the wire contacts are clean and properly aligned. If you have the capabilities, check the Dec cable for continuity. The RJ12 connectors are known to have connection issues. If you have the crimping tool or know someone that does, try re-crimping or replacing the connectors. The next thing you will want to check is the connections from the MC board to the power board and the connection from the Dec board in the Dec cover to the motor. You can swap the Dec and RA motor connectors on the motor board and see what results you get. If the dec motor runs, but the RA motor is now inop, then the problem is with the board. If the Dec motor still doesn't run the problem is with the Dec motor or connections.
Posted 08 July 2012 - 12:43 PM
If it's dead silent, the procedure in Stan's post above is what you're doing.
If it clicks or bumps or grunts, but doesn't turn, then check the leads to the motor and make sure no debris is in the gears. Or it may be the motor has died. As a last resort you can try pulling the motor out of the drive train and make see if it and the worm function normally apart.
If the motor runs at full speed but the axis doesn't move, look for a loose gear set screw. If the mount had this problem its accuracy in GOTO should have mysteriously dropped off shortly before the failure.
Posted 08 July 2012 - 08:19 PM
In my case I know the DEC motor is good so now I just need to isolate the issue. Could be the DEC board but I don't think so. (Recently replaced) Could be the main power board (which is only $20). Could be the motor board as well but I don't think it is since that has already been replaced also.
Posted 08 July 2012 - 10:40 PM
Of course, I was fully expecting the DEC axis to be inoperable again. So I planned to just align the sun as best as I could and let the RA motor handle the tracking. Lo and behold, the DEC axis was working after setting it up. So, I'm very happy that it's not dead.
However, I am still concerned that there may be a growing problem. I've had several instances in the past couple months where my GoTo mount has just stopped working in one axis or another. If this continues to happen, I will definitely keep a log of which axis is acting up and the circumstances surrounding it.
To answer rdandrea's question, I received no error on the hand controller. The DEC axis just wouldn't move. I could not hear whether the motor was still running or not as there were many people talking around me. The hand controller continued to display the spinner indicating that it was still trying to slew, but it wasn't moving anywhere.
Posted 09 July 2012 - 07:16 AM
Posted 09 July 2012 - 10:11 AM
If you do not see and obvious problem with the DEC cable, then you should remove the RA motor housing and take a look at the cables. If the cable is damaged, but not too bad, then some electrical tape will take care of the problem.
Posted 09 July 2012 - 03:12 PM
Ed, I will definitely take the casing apart and check on the wires inside to be on the safe side. The DEC axis seems to be working fine again now. It operated flawlessly for several hours yesterday in the blazing sun as I had the scope set up for solar observing at my nephew's birthday party. So, it definitely seems like an intermittent issue, but I want to take care of it before it gets worse. BTW, thanks for a great product. I purchased the DIY Hypertune kit a year and a half ago and tuned up my mount real good. Works great now; nice and smooth with no more backlash!
Posted 12 July 2012 - 07:24 PM
Posted 13 July 2012 - 11:52 PM
I was able to manually point my scope and then engage the clutch on the RA access to keep it tracking. So the evening wasn't shot by any means. Just took a little longer and a little more fussin' to get things centered. Thank the stars for GLPs and finder scopes!
I'm definitely going to have to try and find time this weekend to take the casing off the DEC housing and see what's going on in there. I really hope it is an easy fix.
Posted 14 July 2012 - 09:11 PM
Posted 30 July 2012 - 12:53 AM
I thought I had it licked this time. A week or two ago, I had taken the housing off the DEC motor and checked to make sure all wires were okay. Everything seemed to be in good order. Lots of testing after that with the mount only didn't turn up any problems.
Now that I've gone back and re-read some of the suggestions here, I see that Ed recommended opening up the RA housing (not the DEC housing) to check that the wires from the motor board to the DEC connector are okay. I'll have to try that next. Also, I'm wondering if I should just go ahead and get a new DEC cable to be on the safe side. Another thought is whether it's possible the hand control could be having some type of problem that may cause this?
Posted 30 July 2012 - 09:45 AM
Unlikely it's the HC at all. If the HC can no longer talk to one of the motor controllers you'll get an No Response 16 or 17 error message. Just stopping is usually a cabling or problem with the motor itself.
I'd follow Ed's suggestions very closely, he probably has more experience working with the internals of the CG-5 than all the rest of us on this thread combined.
Posted 30 July 2012 - 11:34 AM
Posted 30 July 2012 - 11:37 PM
Once I pulled the DEC housing off, the DEC motor started working again. I'm thinking that maybe the wire connection on the back of the DEC socket jiggled loose somehow. I can't be sure as I don't remembered exactly what I did just prior to the DEC motor working again. Could have been a couple different things.
In any event, I grabbed a roll of electrical tape and taped down all the wire connections on the boards and sockets just to make sure that stay nice and secure. I sat in my kitchen/"workshop" and put the mount through its paces without the OTA or any counterweights. It works perfectly fine now. I won't know for sure if I finally fixed my problem until I get out in the field with my setup again for a few hours at a time. I really hope I got it taken care of this time.
Posted 05 August 2012 - 08:59 AM
The reason for the issue with my (almost) brand new CG-5 dec motor was a loose connection in the RA casing, right behind the Dec port on the board. Note that it was not the connection of the Dec port to the board, but rather the connection of the cable to the board, behind the dec port. A little playing around and my dec motor works normally now. Note that visually there was absolutely nothing wrong, I just had to move the connector to the sides a few times before my mount started working again.
I guess the issue might re-occur, but I will think of a permanent solution if it comes to that.
Hope this helps, in case anyone stumbles on the same problem (God forbid).
Posted 13 August 2012 - 12:52 AM
Tonight, I was volunteering at an outreach event/Perseids Meteor Shower Party. My DEC motor wouldn't work at all from the moment I powered up the mount. I have no idea where to go from here. Which part I should fiddle with, fix, or try to replace. From all accounts that I have read in my research on this problem, it could be anything from the DEC cable to the Power Board to the Motor Board to the wires rubbing on the housing to the DEC motor itself.
So, which part(s) do I start trying to replace first? I guess I'll start off with the cheapest ones and work my way up from there. I'll get the DEC cable, DEC board, and Power Board first. If those don't fix the problem, then I guess it's on to the more expensive items on the list. Let's see what happens. Keeping my fingers crossed!
Posted 13 August 2012 - 04:21 AM
Posted 13 August 2012 - 02:04 PM
The couple of times I've had the mount inside to take off the covers and inspect everything, I did not have my OTA on the mount. I just had the mount on the tripod while working on it. So, I don't know if it is the DEC motor really starting to go out and it is able to work fine with no load on it. And then once I put the OTA and counterweights on, it is too much for the the DEC motor. Or maybe there is something else loose somewhere, and packing up my mount and transporting it knocks that connection loose every time. I don't know. So, I am going to start by replacing the cheaper parts inside and then test it out under full load. If the DEC motor still cr@ps out on me, then I know it is either the motor itself or the Motor Board. At that point, I will perform your test to see if it is the motor or the board. We'll see!
Posted 17 August 2012 - 11:21 PM
Posted 17 August 2012 - 11:54 PM
turned out to be a broken wire. the wire was broken on the inside, but no damage to the insulation. I found it by stretching the wires.
Posted 18 August 2012 - 01:32 AM
UPS says replacement parts should be delivered this coming Tuesday. So, now my question is: does ordering mundane, internal repair parts invoke the astronomy curse? I would hope not. It's not like this is some new EP or other astro toy that I'm really excited to get. I'm just trying to fix my broken mount!
Ordering the parts doesn't. Getting the mount fixed an working does.