CPC 1100 Main power adapter

[Simon128D]

Hi all, 
I've just recently become the owner of a lovely CPC 1100 and couldn't be happier but after being out last night to watch Callisto's shadow transit on Jupiter the scope was having moments of struggling to slew at full speed and tracking was just not happening - like it was at half speed. 
I have been using a Halford's 20ah power tank to power all my gear for years now but I am suspecting that it is not up to snuff for the CPC, thus before I go out and buy an expensive Lithium power pack - to replace the Halford - I thought I should buy a mains power adapter to use at home. 

I came across this on amazon and wondered if anyone had any thoughts on it? 
https://www.amazon.co.uk/gp/product/B07N1WTGWM/ref=ox_sc_act_title_1?smid=A850CZQOZ8GYC&psc=1

Or would this on FLO be a more sensible option? 

https://www.firstlightoptics.com/batteries-powerpacks/nevada-ps-08-6a-8a-regulated-linear-power-supply.html

If anyone can recommend something else? 

Edited August 12, 2020 by Simon128D

[Cosmic Geoff]

Depends on whether you want to just run the mount or an assortment of dew heaters, laptops, focusers, etc etc as well.  Anything that provides the right volts and amps should work.  Be aware that some PSUs (like the Nevada) will permit you to reverse the polarity, with terminal results!  Your Halfords power tank could be life-expired, as lead acid cells don't last very long.

I use an engine-starter as a DC battery power supply and it works fine.

A couple of tips:

Run the DC power lead through one of the lift handles to stop it flopping about and breaking the connection.

Slacken the azimuth clutch off and spin the mount/OTA around though 360 degrees. It should carry on going under its own momentum.  If it is binding, this will affect the tracking and you may also hear the gear whine changing as it slews.  This is a known issue and can be fixed by opening up and adjusting the mount.

[Simon128D]

I only want to power the scope, nothing else. I am 95% a visual astronomer. Everything else I can power from something else. 

I haven't tried to spin the mount around when when I did unlock the clutch it certainly did not feel like it was free enough to be spun around. I will try that again when I next use it. I am new to SCT scopes. I am usually a Newt, dob or on EQ6 so not sure what binding is or what I would need to be looking at if I need to open it up. 

I am really tankful for your advice though. 

[Simon128D]

Geoff, 
I just set the scope up there to check software versions and do some updates and I tried to spin the scope as you said but even with some force on the handle it is only moving about 40 degrees and stops so there must be binding going on. Can you point me to any material that could show me what I need to do? 

 

[Cosmic Geoff]

Yes, it does seem you have a problem with the azimuth bearing area.  As I said, it should be free enough to move with minimal force and spin through an angle under its own momentum.  If you search around on Cloudynights and elsewhere you may find some discussion of the issues.

These instructions tell you how to replace failed nylon bearing balls with steel ones:

https://nexstarsite.com/download/CPCHowToReplaceFactoryOriginalNylonAzimuthBearingBalls.pdf

But if you just need to inspect, the procedure is essentially the same.  In my case, slacking off the 45mm centre nut sorted the problem.

Edited August 12, 2020 by Cosmic Geoff

[Simon128D]

Thanks again,
Yes I found that pdf and is excellent. I was able to take the mount apart and could confirm I have the nylon bearings and want to replace them now. 
I am unsure what bearing size I need to order. The PDF and all other references I found online state they are 0.25" bearing but to convert that in mm comes to 6.3mm and I cannot find bearings of that size, 6mm is the nearest and I am not sure if they will do. 

Upon reassembling the mount - so I could put it back into its case - I powered it on and the slewing is much improved but the movement my hand is really rough. 

 

Believe I found them 
https://simplybearings.co.uk/shop/p222116/1/4-inch-Diameter-Grade-100-AISI-316-Stainless-Steel-Ball-Bearings/product_info.html

Edited August 12, 2020 by Simon128D

[Cosmic Geoff]

I'm pleased that you have pinpointed the problem.  I'd definitely use balls described as 1/4" if I were you.