ServoCAT system repaired and working great!
I am amazed by how well my UC18 is tracking now that I replaced the broken plastic gear. Makes me wonder how long it had been at least partially damaged. I figured out that it is so important not to over tighten (stress out) the set screws through the plastic part onto the steel shaft.? Just snug rather than "tight". My idea is that I damaged the part by not being careful with my accessories under the VMB and allowed an interference to occur. I have reorganized my accessories to prevent any chance of interference to the path of the primary mirror as it travels over the rocker.  Here is M76 (a difficult target for me) from my UC18.
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Gary,
When I installed the slotted teflon slide to support ServoCAT I wondered if the UC would benefit if both sides had the slotted teflon and perhaps wider slots.
Richard
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Richard,
Note that wasn't necessarily specifically addressed to you re balance... but I will add this caveat to UC owners out there.
The UC is a different beast in that it has full length Teflon pads on the ALT axis. This was done by Dave to prevent a visible bump when the part of the foldable ALT bearing hit the edge of the pad (if normal length, i.e. shortened). BUT that adds a good deal of stiction. Contrary to belief Teflon is not friction-less.... it is just low friction. You add a thin layer of dust to it and it starts to add up. The bottom line is it is not unusual for an imbalanced scope to "appear" balanced if you just move the axis and let go - and it stays stationary. That tests does not apply here (of course if you do that and it moves then you might seriously consider checking the real balance!). Its best to use a force gage to confirm what the friction is.?
Gary Myers
------ Original Message ------
Date 11/7/2023 2:42:59 PM
Subject Re: [ServoCAT] Dont do what I did!
I "can't" turn the VMB 90 deg due to my addons so I just shortened the counter weight tube and remove the secondary to fit into the Pelican case.
I am going to follow the rule in boy scouts to make sure you can't hit anything with your axe before you start to swing.
I think I have the scope balanced well, so my issue is to just make sure there is clearance to stuff on my deck and under the VMB in the rocker.
Richard
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I "can't" turn the VMB 90 deg due to my addons so I just shortened the counter weight tube and remove the secondary to fit into the Pelican case.
I am going to follow the rule in boy scouts to make sure you can't hit anything with your axe before you start to swing.
I think I have the scope balanced well, so my issue is to just make sure there is clearance to stuff on my deck and under the VMB in the rocker.
Richard
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Yes indeed!?
The 18UC was a difficult design for fitting a ServoCAT as the criteria given to me by Dave at the time, when he dropped off the prototype, was that it not only had to "work" as normally set up - but that it also had to be able to go in to a pelican case for transport.?
That ultimately meant there were TWO designs. One for normal use - and one where the user picked up the VMB, turned it 90 degrees, and set it down on top of the rocker which was in the case. WITHOUT damaging or impacting anything else. This was not an easy task.?
The end result is the pulley design for the ALT will work perfectly well in a normal usage. But when people start to overload that axis without considerations of counterweights - and/or when they do something to stop the axis mechanically - it can damage that pulley.?
I was never able to find a metal one for that use.?
Gary Myers
------ Original Message ------
Date 11/7/2023 1:29:26 PM
Subject [ServoCAT] Dont do what I did!
Dont let your scope hit anything while slewing! ?And dont over tighten the set screw.
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Dont let your scope hit anything while slewing! ?And dont over tighten the set screw. 
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Re: Oops, I broke my sprocket
I have sent another email.
BC
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Re: Oops, I broke my sprocket
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Re: Oops, I broke my sprocket
Richard:
I have sent you an email off-list.
Bill Conrad
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Richard, ? Sorry to hear of your issues with the tracking system on your UC.? Hope you can get it fixed fairly quickly. ? Jack ? Jack Huerkamp Jack's Astro Accessories, LLC 38388 Pine Street Pearl River, LA 70452-5192 985-445-5063 mallincamusa@...
30.37N? 89.76W ? All of us get lost in the darkness.
Dreamers learn to steer by the stars. ¡¡¡¡¡¡¡¡¡¡¡¡¡.Neil Peart ? ? ?
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From: [email protected] < [email protected]> On Behalf Of Richard Sent: Monday, November 6, 2023 9:27 PM To: [email protected]Subject: [ServoCAT] Backlash ? I think I know what may have happened.
I have too much stuff now in my rocker and while moving the Alt I think my mirror impacted something and halted the scope.
After this is when I noticed the backlash.? I am now guessing that is when I damaged this sprocket.
You can watch the set screw locations on the brass part and the sprocket part move out of sync with each other (large backlash).
I will rearrange all my stuff in the rocker of the UC or move it to outside the scope so there is no danger of any impact.
Hopefully I can get a replacement part to restore my scope's operation.? I am really liking my new camera.
Here is my last photo before I broke the sprocket.?
Richard
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I think I know what may have happened. I have too much stuff now in my rocker and while moving the Alt I think my mirror impacted something and halted the scope. After this is when I noticed the backlash.? I am now guessing that is when I damaged this sprocket. You can watch the set screw locations on the brass part and the sprocket part move out of sync with each other (large backlash). I will rearrange all my stuff in the rocker of the UC or move it to outside the scope so there is no danger of any impact. Hopefully I can get a replacement part to restore my scope's operation.? I am really liking my new camera. Here is my last photo before I broke the sprocket.?  Richard
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Oops, I broke my sprocket
Gary, I broke my sprocket while attempting to remove my backlash.? I over tightened the set screw and broke the sprocket. Any advice--can Bill sell me a new sprocket? 
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Re: [>|ServoCAT] New camera-more power through my powered ground board
Gary, ? Will do. ? Richard ? ? be sure to use 2 diodes so that neither backfeeds the other.?
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------ Original Message ------Date 11/5/2023 4:30:44 PM Subject Re: [ServoCAT] New camera-more power through my powered ground board Gary,
I will try your suggestion of a diode switched LiFePo battery. ?I love fault tolerance designs!
Richard
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Re: New camera-more power through my powered ground board
be sure to use 2 diodes so that neither backfeeds the other.?
------ Original Message ------
Date 11/5/2023 4:30:44 PM
Subject Re: [ServoCAT] New camera-more power through my powered ground board
Gary,
I will try your suggestion of a diode switched LiFePo battery. ?I love fault tolerance designs!
Richard
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Re: New camera-more power through my powered ground board
Gary,
I will try your suggestion of a diode switched LiFePo battery. ?I love fault tolerance designs!
Richard
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Re: New camera-more power through my powered ground board
Richard,?
I don't know if you have my PGB or not - I believe you do (and you would if it is an Obsession 18UC). I think Mickey has a different one supplied by StarStructure.?
The spring pressure on the redundancy plate is critical - and over time the screw has been known to loosen up (the center screw that provides that pressure). I'd check that out.?
The brushes are phosphorus bronze. They can corrode a bit over long periods of time especially if near salt air. But generally just removing them (that same screw above) and cleaning them once every other year should do a perfectly fine job. I'd remove the bushings and put a pencil eraser in and run it around a few times to clean the contact plate as well. NOTE that we did have issues with those bushings NOT being installed correctly. We've had more than a few that the brushes were cocked due to the hole being non-perpendicular to the floor. If that is the case I'd recommend drilling those holes (BE CAREFUL NOT TO GO FURTHER THAN THE DEPTH OF THE HOLE) with a 13//32" drill bit to allow them to readjust as needed.?
Note you are drawing more current than it was designed for. The system nominally, w/o all the extra hardware you have, would see an average current of about 400mA when tracking and supplying the ServoCAT and a DSC... and a peak (and very brief) current w/ both axes slewing of maybe 2.5 - 4A depending on the scope size and more importantly depending on how well the scope was built re static friction (and believe you me - it can be a substantial difference with some scopes - HUGE frictional forces I've seen). So if you are averaging as much as 4A you're peaking closer to 8 probably.?
You might consider just putting a LiFePO4 battery inside the scope... you could either have it run everything or you could have it diode isolated to automatically power the system if there is a momentary interruption. if you do that it should never 'stop' as it would ride through the very brief interruption. I'd use high current shottky diodes to do this as they can be found with a Vf of about 0.4V. By isolating you won't run it down - and would just need to top it off once a month or so.?
Also if you remove that screw - I'd suggest you get a #2 pencil and shave off some wood chips - stuff them in to the hole so that it has a good purchase when reinserted. Otherwise it will be looser and it could unscrew as mentioned above.
Gary?
fantastic shot - can you show it WITH the stars? I'd be curious to see that as well.?
------ Original Message ------
Date 11/5/2023 10:57:08 AM
Subject Re: [ServoCAT] New camera-more power through my powered ground board
Mickey,
The Eagle4S has power distribution and measures voltage and current for each port. ?It also has a sky quality meter. ?It runs all my software: ?MallincamSky, Stellerarium, play, my VB.net software and database, ASCOM drivers, Eagle Manager X and I connect with MS remote desktop. ?
I have considered changing the contact design away from dissimilar metals. ?If you remember the channel selector on TVs built in the 1960s they always used silver plated contacts on both the leaf spring and the circuits since silver oxide is conductive. ?But for large DC current it is better to use another metal to avoid silver migration. ?I am thinking of plating both the springs and plate with a noble metal¡ªperhaps gold.
Richard
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Re: New camera-more power through my powered ground board
Mickey,
The Eagle4S has power distribution and measures voltage and current for each port. ?It also has a sky quality meter. ?It runs all my software: ?MallincamSky, Stellerarium, play, my VB.net software and database, ASCOM drivers, Eagle Manager X and I connect with MS remote desktop. ?
I have considered changing the contact design away from dissimilar metals. ?If you remember the channel selector on TVs built in the 1960s they always used silver plated contacts on both the leaf spring and the circuits since silver oxide is conductive. ?But for large DC current it is better to use another metal to avoid silver migration. ?I am thinking of plating both the springs and plate with a noble metal¡ªperhaps gold.
Richard
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Re: New camera-more power through my powered ground board
Excellent image Richard. As for the ground board contacts buried in the bottom. Every year since I had the problem you describe, (losing power) I disassemble the scope and remove those little copper contacts from the underneath of the ground board, clean the contacts and make sure the stings have plenty of spring left in them. No need to data log, I guarantee you the contacts need cleaning. ? So are you using the EagleS4 instead of a separate stand alone router for your remote control Wi-Fi?
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On Nov 4, 2023, at 9:06 PM, Richard <rmille64@...> wrote:
?All, I now have a bunch of gear on my UC18.? A Win10 PC with an I3 processor (Eagle4S pulls one amp just for itself), a motorized focuser, Mallincam DS10CTEC, Pegasus USB 3 Hub, dew heater, filter changer, and the ServoCAT gear.? My average current draw is 2 to 3 amps out of the battery.? I have a 10 amp 12 volt DC-DC converter in the rocker next to the ServoCAT electronics that powers all my gear. After a few hours the Eagle4S turned off as the temperature approached freezing--I had plenty of power reserve left in my 55-amp hour battery.? I replaced the battery with the AC to DC power supply I bought from Gary for the powered ground board. Worked for a few hours then the Eagle4S shut off again. I am thinking it is time to do some maintenance on my rotating contacts on the powered ground board.? I need to data log my input voltage variation to help troubleshoot.?? Anyway, while I still had several hours of operation, I got a photo of the Pacman and a few other targets. Richard <NGC281.jpg>
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New camera-more power through my powered ground board
All, I now have a bunch of gear on my UC18.? A Win10 PC with an I3 processor (Eagle4S pulls one amp just for itself), a motorized focuser, Mallincam DS10CTEC, Pegasus USB 3 Hub, dew heater, filter changer, and the ServoCAT gear.? My average current draw is 2 to 3 amps out of the battery.? I have a 10 amp 12 volt DC-DC converter in the rocker next to the ServoCAT electronics that powers all my gear. After a few hours the Eagle4S turned off as the temperature approached freezing--I had plenty of power reserve left in my 55-amp hour battery.? I replaced the battery with the AC to DC power supply I bought from Gary for the powered ground board. Worked for a few hours then the Eagle4S shut off again. I am thinking it is time to do some maintenance on my rotating contacts on the powered ground board.? I need to data log my input voltage variation to help troubleshoot.?? Anyway, while I still had several hours of operation, I got a photo of the Pacman and a few other targets. Richard 
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Jack Huerkamp