29 replies to this topic

[ObservatoryCat]

Hello Everyone,

Here is what I have accomplished to try and find the cause of the problems.

Inspected every millimeter of the wires from the DB-25S connector at the motherboard to the connection on the declination servomotor control board. This included removing all tywraps. Only damage found was slight crushing by the tywraps and the cover at the RA axis.

Meggered the above wires (250 volts) wire to wire and wire to connector shell. All were infinity except for the DB-25S connector at the motherboard which had 50 mega ohms. Makes me wonder what is going on there but I do not think it will cause problems. Real pain to replace.

Checked continuity of above wires, all good.

Inspected all other wires, as possible, found no faults.

I inspected the hand box, declination servomotor control and mother boards with my microscope. Declination servomotor control board was okay, Hand box was okay, found one tiny drop of solder that was across two traces but it had not done any damage, no copper showing. Main board had one bad joint. Negative pin for the back-up replaceable battery had solder all around it that looked nice and shiny on the outside but the pin, which was sticking through, was loose. Could not fall out because the battery holder kept it in place. Fixed solder joint and replaced battery, which was dead. Can not remove the other boards with the scope mounted.

I got a borescope (only good way to do it), and looked at the connectors on the RA servomotor control board, all good, connectors and all wires looked secure.

I had noticed, but made it a low priority, that there was a glob of silicone sealant on the connector at the dec motor encoder. Thought it was just an extra security feature. I looked there in the past and did not see any bare wire. The RA encoder had no sealant on it. Removed the sealant and all four of the wires fell off! Part of the wire end connector was broken and sprung up so that it did not lock the wires in place. Sealant was there to keep them in place. Removed the dec motor so that I could put it under the microscope and also work on it easier. Could not remove the broken piece of the wire end connector from the receptacle on the encoder. Reinstalled the wires, folded down the broken and sprung up piece and resealed. I do not feel this was the cause because the connector look good except for the sealant. 

The above were the last steps I could think of to do, so reconnected everything back up and scope ran for about 50 minutes without any craziness before I had to shutdown. Not a good test, but a start. 

ObservatoryCat

[Cefiar]

ObservatoryCat:

Good to hear you seem to be getting somewhere with your scope. As someone who started out as an Electronics Tech, I definitely like seeing posts like this that explain what you've found and how you went about it.

Fingers crossed you've solved the issue.

[MistrBadgr]

This is great news!  

If you did not fix the current problem, I bet you fixed some future ones.  However, I am hoping that you fixed the current problem as well.

Please keep us current on what you experience.

Best Regards,

Bill Steen

[Cefiar]

ObservatoryCat:
One of the people I know online who has an LX200 (Paul Stewart, who is in NZ) recently opened up his LX200 mount to service it, and posted a few pics of the guts of it.

You can see his post here: https://plus.google....sts/NnwH8nzQxzg

He's had the mount open a huge number of times tweaking stuff, so if you need some reference pics of various parts, I would definitely ask him.

[ObservatoryCat]

Hello Cefiar

I have looked at the images. They are of a 12" LX200 which is quite different from my 16".

I am in the process of building a beam, that will rest in the shutter tracks of my Ash Dome, to which I can attach a small hoist to be able to lift the 125 pound OTA of the 16". I want to dismount the telescope and move the inaccessible RA servomotor control board to a place where I can get at it. This will also allow me to make an adapter wire harness so that I can attach the motors to a different control system which I can get customer support for.

I have a good image of the declination worm gear assembly which I will add to my photo site, shown above, in the next couple of days. Will take an image of the right ascension worm and post it also when I can get to it.

Got one and one half hours of telescope ops, without any problems, last night before I was stopped by clouds. Perhaps just reseating the connectors was all it really needed?

Ordered a new wire end connector (not from Meade) to replace the broken one mentioned above.

Thank you for your comments.
ObservatoryCat

[ObservatoryCat]

Hello Everyone,

Had six and one half hours of trouble free operation last night (03/04/2013) before the stratus clouds rolled in off the bay. That makes 9 hours total now. Sure is nice. Only problem is that I don't feel like I can ever be away from the scope when it is running. Wish there was some automatic procedure that I could activate when I want to leave for a little while that would stop any excessive slewing.

Really do not know what I did to get it operating correctly.

ObservatoryCat

[MistrBadgr]

I would bet a vanilla cookie that the bad connector or broken wire had something to do with it.  Either that or you had your mouth set right when you waved your magic wand!

By the way, I like the picture of the cat.

Bill Steen

[ObservatoryCat]

Hello Everyone,

Have you gotten any good images of or looks at Comet PanSTARRS? I cannot see it from My Observatory due to trees but have seen it with binoculars and taken some images of it with my Nikon D700 and a 70-300mm lens. Sure is fun to see a comet with a tail for such a long continuous time, first saw it on the 12th. This is a first for me, to be able to watch one for so long in twilight.

There is a fairly bright supernova in M65 (16 magnitude). I got an image of it on the same night that it was discovered (03/22/2013) but the moon is getting very close now. Have already had 61 people look at my posted image.

The telescope is working great, no runaways. Replaced the broken receptacle on the wires that attach to the declination servomotor encoder, used Stabilant 22, and have completed the telescoping bar that fits in the shutter tracks so that I can lift the OTA with a small hoist. Just need the ambition and some cloudy skies to get to work and take it down so I can reposition the RA servomotor board.

ObservatoryCat

[d33d0gg]

I just checked out your image of M62 on your flickr page, amazing shot!

[ka1bqp]

ObservatoryCat, on 26 February 2013 - 09:15 AM, said:

Hello Everyone,

Here is what I have accomplished to try and find the cause of the problems.

Inspected every millimeter of the wires from the DB-25S connector at the motherboard to the connection on the declination servomotor control board. This included removing all tywraps. Only damage found was slight crushing by the tywraps and the cover at the RA axis.

Meggered the above wires (250 volts) wire to wire and wire to connector shell. All were infinity except for the DB-25S connector at the motherboard which had 50 mega ohms. Makes me wonder what is going on there but I do not think it will cause problems. Real pain to replace.

Checked continuity of above wires, all good.

Inspected all other wires, as possible, found no faults.

I inspected the hand box, declination servomotor control and mother boards with my microscope. Declination servomotor control board was okay, Hand box was okay, found one tiny drop of solder that was across two traces but it had not done any damage, no copper showing. Main board had one bad joint. Negative pin for the back-up replaceable battery had solder all around it that looked nice and shiny on the outside but the pin, which was sticking through, was loose. Could not fall out because the battery holder kept it in place. Fixed solder joint and replaced battery, which was dead. Can not remove the other boards with the scope mounted.

I got a borescope (only good way to do it), and looked at the connectors on the RA servomotor control board, all good, connectors and all wires looked secure.

I had noticed, but made it a low priority, that there was a glob of silicone sealant on the connector at the dec motor encoder. Thought it was just an extra security feature. I looked there in the past and did not see any bare wire. The RA encoder had no sealant on it. Removed the sealant and all four of the wires fell off! Part of the wire end connector was broken and sprung up so that it did not lock the wires in place. Sealant was there to keep them in place. Removed the dec motor so that I could put it under the microscope and also work on it easier. Could not remove the broken piece of the wire end connector from the receptacle on the encoder. Reinstalled the wires, folded down the broken and sprung up piece and resealed. I do not feel this was the cause because the connector look good except for the sealant. 

The above were the last steps I could think of to do, so reconnected everything back up and scope ran for about 50 minutes without any craziness before I had to shutdown. Not a good test, but a start. 

ObservatoryCat

I've been following this thread for a while now, (I just joined.) and I'm glad to see that you were able to solve your problem. I agree with Cefiar, as I am also an ET by trade. It was great to see the explaination of your problem and the steps you took to rectify it.

I also own an LX200 but mine is considerable smaller as I need to travel to find dark skies, especially since they fixed the streetlamp near my home. (I'm still mad at my wife for complaining to the electric company. )

I wish Meade would offer tech manuals and part support for those of us who are capable and qualified to make our own repairs, or don't want to (or can't)ship our equipment back for factory service. Before I bought the LX200, I had purchased a 6" LS. Nice scope, but it had a problem with the SD card reader. I had to ship it back to Meade and it took over three weeks before I got it back. Somewhat disappointing for a brand new piece of equipment. In fairness to Meade, the scope has worked flawlessly since it was repaired at the factory. A good friend purchased it from me when I decided I needed a bigger scope.

Clear skies,
Matt