The other night my guiding went haywire using my 900GTO.  It's worked flawlessly for several months so I initially thought I was having a software problem.  Essentially, after about 60 seconds of guiding dec would drift a little bit and despite PHD sending corrections, it would not respond.  To compound the issue, not only was DEC calibration failing in PHD, but also RA was requiring about 25 steps to clear the backlash. 

I spend a couple of hours debugging software, trying to see if APPC model correction could have impacted it.  I also changed PHD versions, and rebooted gear several times.  I checked my balance and fine tuned... I dialed in my PA (observatory mounted) but nothing seemed to work.

My last ditch was to see if there was a backlash issue, which in hindsight based on the behavior should have been my first check.  Sure enough, there was wiggle in DEC.  RA was solid.  The locking bolts for the motor/gearbox were gorilla tight, but following the AP PDF I remeshed in about 30 seconds and all of my problems were solved!  Gotta love this user friendly design to allow a quick and easy field adjustment.  In the PDF it explained that seasonally the mesh may need to be tweaked, so I assume that my wild Vermont temperature swings led to this. 

Well, now I know!  Of course, those of you who have mounts that automesh dont need to worry about this, but thought I would tell the story as there are a TON of older mounts out there that are faithfully performing like a champ!

Steven,

 

Please use my email below.   

 

Regards,

 

George

 

George Whitney

Astro-Physics, Inc.

Phone:  815-222-6538 (direct line)

Phone:  815-282-1513 (office)

Email:  george@...

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Steven Panish
Sent: Tuesday, August 3, 2021 1:59 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Debugging Dec failure to move w/1200 CP3

 

Thanks George.  I considered freeing up the box, but that mucks up my cabling.  A new y-cable will be here tomorrow and **maybe** that will work.  If not I'll give you a call since the issue is deeper, and at that point I really will need to start taking things apart.

 

Steve

 

On Mon, Aug 2, 2021 at 10:12 AM George <george@...> wrote:

Steve,

 

If the cable won’t come to the box, take the box to the cable!   You have to free the CP3 from the mount and then reverse the cables…yes, the box will dangle in the air.

 

Regards,

 

George

 

George Whitney

Astro-Physics, Inc.

Phone:  815-222-6538 (direct line)

Phone:  815-282-1513 (office)

Email:  george@...

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Steven Panish
Sent: Friday, July 30, 2021 10:29 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Debugging Dec failure to move w/1200 CP3

 

Unfortunately the RA branch of the y-cable is too short to make it to the DEC motor connector.  I may be able to pull off the CP3 and get the cable to connect to the DEC motor.  I did put the DEC cable onto the RA and the motor did not come on.  So that would support the idea that there is a fault in the cable or CP3.  

 

There is no visible corrosion on any of the connector pins.  They do not appear to be gold plated, this is an old mount. I put DeOxIt on the female connector sockets.  Didn't help.  I'll open the CP3 up and see if any corrosion is visible.  Seems unlikely, this is in an observatory, but NH does get humid.

 

There are no software limits set that would do this.  The problem appeared out of the blue.

 

Guess I'll order a spare Y cable next week.

 

Steve

 

On Thu, Jul 29, 2021 at 4:06 PM Jeffc <jeffcrilly@...> wrote:

 

 

On Jul 29, 2021, at 12:00 PM, Christopher Erickson <christopher.k.erickson@...> wrote:



Also consider getting a spare motor Y-cable and try that. EVERYONE should have a spare motor Y-cable in their kit. A spare power cord too.

 

Fwiw.. I also have a spare Y-cable for the 1200.

I broke the original cable once, and fixed it… but after that incident I decided to get a spare just in case. 

 

 

And there is an outside chance that a software axis limit setting is involved.

-Christopher Erickson
Observatory engineer
Waikoloa, HI 96738
www.summitkinetics.com
   

 

On Thu, Jul 29, 2021, 11:50 AM Manusfisch via groups.io <tjfischer653=mac.com@groups.io> wrote:

Wasn’t there a problem with the CP3 where the inside board became loose or had a corroded connection inside the box that might make intermittent problems come up with power to the motor or control to the motor? I don’t have a CP3 just a later model CP4 so I can’t really comment technically I just remember a conversation

TJF Mobile

 

On Jul 29, 2021, at 08:18, Steven Panish <scpanish@...> wrote:



Eric,

The CP3 is connected through a serial/usb converter, but the RA still responds to a nudge even when the DEC does not, so the port is still alive.   And the handbox shows the same issue.  I think the fault has to be later in the path than the comm between the PC or handbox and the CP3.  Although I don't know the architecture.  Good thought though.

Steve

 

 

 

On Thu, Jul 29, 2021 at 11:09 AM Eric Dreher <ericpdreher@...> wrote:

Some will sleep, removing power from the port when it's considered inactive.

Well, I was just called by my favorite "Karen" tonight and I will soon be the owner of a new Stowaway. I can't believe my good fortune. Now, do I want the flattener or the reducer? Decisions ... decisions...

Kevin

Tom

This question comes up over in general imaging forums.  Some 'interesting approaches arise.

See  https://www.cloudynights.com/topic/408507-mount-balance-meridian-flip-and-automation/

Thank you, Roland and A-P, for a more elegant solution!!
"Our mounts have spring loaded worms, so do not need to be unbalanced."

Bryan

For Astro-Physics mounts best practice is to balance. Our mounts have spring loaded worms, so do not need to be unbalanced.

Rolando

-----Original Message-----
From: Tom Blahovici <tom.va2fsq@...>
To: main@ap-gto.groups.io
Sent: Fri, Aug 6, 2021 1:52 pm
Subject: [ap-gto] Balance: what happens at Meridian flip?

Hi

I have read that best practice is to have the balance heavier on the counterweight side when imaging to the east. Ok, makes sense.
However what happens at Meridian flip? It's now completely wrong.
Explanation?
Tom

--
Roland Christen
Astro-Physics