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CPC1100 complete overhaul

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#1 Escher

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Posted 15 February 2013 - 09:16 AM

I'm in the process of overhauling my CPC1100. As you have read in my other thread in the CPC forum, my motor board died so I'm waiting on a replacement...

While I'm in there I may as well do it all.

Current plans:
- Motor Board swap (and any other electrical issue I find along the way)
- New bearings and Moly lithium grease
- Regrease and adjust all drives (currently had the "clunk/tick" issue)
- Flock tube
- (If I can get the funds together) Feathertouch focuser


Anything else I should do while I have it gutted? I was thinking about active cooling, but since it lives in a dome, I dont see the need...

I'll be posting pics of the process...

#2 jerwin

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Posted 15 February 2013 - 08:27 PM

I think you have it covered. I'll be interested to follow your progress.

Jim

#3 Escher

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Posted 15 February 2013 - 09:29 PM

Ok... so here are some initial pics of the disassembly.

First - the base - no logic boards, just simple connector boards and power.
Posted Image
Cpc1100 disassembly by Christopher Purdy, on Flickr

Now the Right side arm - if facing the control panel - this has the GPS interface board and the GPS unit at the top.
Posted Image
Cpc1100 disassembly by Christopher Purdy, on Flickr

And the Left side arm - this had the Locking clutch, motor and motor controller board:
Posted Image
Cpc1100 disassembly by Christopher Purdy, on Flickr

I did another test tonight to make *sure* my issue is the motor controller board. I unplugged the GPS interface board and powered it on - still stuck at "initializing"... So.. not know exactly what the program code in the handset does - I have to assume it tests each subsystem - ALT, AZ, and GPS... since it never gets out of initializing, and knowing that if a motor fails you will get an error 16 or 17, then I can only conclude that the motor controller is not responding properly.

My new motor board will be here next week.

Next, while I wait for the motor board, I will be doing the base bearing mod, at least inspecting the bearings to start... that should happen Sunday or Monday.

#4 Geo.

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Posted 16 February 2013 - 10:12 AM

Do you have another HC to eliminate that from the boot up problem?

#5 Escher

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Posted 16 February 2013 - 01:40 PM

Unfortunately, no.... But I have re-flashed the firmware several times and it always completes and can be verified... The handset shows hex characters (I think its hex) while the update is being performed... I think its okay...

But - that will be my next course of action if the motor control board doesn't fix the issue.

#6 Escher

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Posted 18 February 2013 - 07:58 AM

I know you guys want more pics - just havent had time... but heres my progress over the weekend:

- Removed main gears on both axes and degreased
- Removed fork assembly from base to expose the bearing balls in base
- cleaned up locking nut on fork base (this thing is an ugly mess)

Just FYI for people looking to do the bearing mod to their base... The large locking nut that you have to remove is a BEAR!!! They used some kindof industrial locktite on it and it took a LOT of force to loosen.. Have a vacuum ready after you get it off since so much of the locking compound will flake off, you dont want to get it into the bearing on the center shaft...

I pulled all the nylon ball bearings out and cleaned up both sides of the channel - I also ordered 200 new chrome 1/4" ball bearings - pretty cheap on the 'bay ($12.00 shipped for two bags of 100).

Ohh and a side note - I was incorrect on the statement "there are no other logoc boards other than the GPS interface and the motor controller"...

It appears that the "PC&AG" board has two small IC's and a voltage regulator on it... at least thats what a quick examination looks like... That board is $23.... Had I known (read: paid more attention).. I would have just ordered it at the same time just in case...

So - No more updates until the bearing balls arrive (although I will try and get some more pics posted)... talk to you in a couple of days...

#7 Escher

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Posted 22 February 2013 - 07:39 AM

Well this is quite the adventure..

Bearing balls and Motor board arrived last night.

I wont keep you in suspense... Its still not working. Same issue. Now it has to be the handset, which I had doubted... but by process of elimination there really isnt much else it could be.

I will probably order the small power board as well since that is only $25 dollars and I really want to just have all the parts available in case its *not* the handset.

So - I ordered a nexstar+ handset from Adorama last night (Alt-AZ model) and it should be here by Tuesday.

But - On with the show - I still had work to do!

Taking the base clutch assembly off:
Posted Image
Cpc repair 2 by Christopher Purdy, on Flickr

And the same for the Arm:
Posted Image
Cpc repair 2 by Christopher Purdy, on Flickr

Gears removed and degreased:

Posted Image
Cpc repair 2 by Christopher Purdy, on Flickr

Removing the Lock nut on the base - lots of nasty threadlock here... this is a pain!
Posted Image
Cpc repair 2 by Christopher Purdy, on Flickr

Posted Image
Cpc repair 2 by Christopher Purdy, on Flickr

Posted Image
Cpc repair 2 by Christopher Purdy, on Flickr

Old nylon bearing balls:
Posted Image
Cpc repair 2 by Christopher Purdy, on Flickr

New Chrome bearing balls and Extreme Pressure moly grease:

Posted Image
Cpc repair 2 by Christopher Purdy, on Flickr

New motor control board (now I have a backup!)
Posted Image
Cpc repair 2 by Christopher Purdy, on Flickr

Testing...

Posted Image
Cpc repair 2 by Christopher Purdy, on Flickr

-------------------

I learned a few new things in the process:
1) You can remove the base and all cables (except the single cable that runs between the two boards in the base) and test wihtout the CPC connected... You can also flash the handset this way.

In theory - I should have gotten "No response..." messages, but once again, never got past the "initializing..." screen.

Another thing I noticed:
2) You can re-assemble the axis locks without putting the skins and such back together... you also dont need to tighten the grub screws on the lock handles - those are just there so you can't take the handles off, but they still function perfectly without using the grub screws.. So you can position the tube with it in a disassembled state as seen in the last pic.

Movement is much smoother due to the new bearings... More updates once the handset arrives!!

#8 Escher

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Posted 25 February 2013 - 09:13 PM

... and thats got it!!

Hand control it is - and a nice upgrade to boot! THe new handset is much nicer!

I made a video of the scope showing the major parts and where everything is located as well as discussion of the mods I did and costs associated with repairs. I thought it would be easier than a bunch of pics.

Video is located here

http://youtu.be/ZxAN4t1PzKo

#9 herrointment

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Posted 25 February 2013 - 11:39 PM

Getting a 404 on the vid but thanks for the photos and update!

#10 Escher

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Posted 26 February 2013 - 12:09 AM

Fixed... I has a trailing colon in the link...

#11 herrointment

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Posted 26 February 2013 - 01:17 AM

Thanks Chris....very helpful vid you did!

#12 Escher

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Posted 29 April 2013 - 02:12 PM

hmmm... link no longer working...

Fixed here:
http://www.youtube.c...h?v=ZxAN4t1PzKo






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