Hi Bryn,

So when the cable in the DEC socket on Gemini was connected to the RA motor, the RA motor ran uncontrollably? That does sound like a problem with the Gemini unit itself. Could be something simple, like the DEC socket not making contact with the PCB (this has been a common failure mode for Gemini-1) or the encoder IC, as Brendan indicated.

If you don't have electronics/soldering skills, you may want to contact one of the repairers closest to you, listed here:?

Regards,

? ?-Paul

Thanks Brendan and Paul,

So I swapped the dec cable to the RA motor and the fault transferred, so immediately thought that the cable was at fault. However, during various other tests, the fault stayed with the RA motor, including the RA motor starting immediately after the hand controller had booted, not immediately.

I have continuity tested both cables and both check out without any continuity issues.?

subsequently, as the fault has switched between motors and the cables pass continuity, The worst case scenario now appears to be the cause, the Gemini 1 control unit!

Given the info above, would this seem to be true?

Paul is spot on swap Ra motor to DEC and visa versa. Keep track of which part started from. ?

You can remove the motors and run them on a bench to test. They don’t need yo be fitted yo test.?

if the fault follows the motor it’s a motor issue?

if the fault stays where it is then it’s a main PCB issue either the H bridge or the encoder IC. Most likely the encoder IC.?

let’s see how you go with the above. ? If needed there who can fix it no problems?

brendan


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Brendan

Hi Bryn,

Continuous uncontrollable slew indicates that Gemini isn’t reading the encoder from the DEC axis servo motor. Things to try:

- make sure the motor cables are not broken by swapping them. If the RA motor runs uncontrollably after the swap, the DEC cable is bad.

- check the DEC motor by connecting Gemini RA to DEC motor and Gemini DEC to RA cable . If the DEC motor continues to run, then there’s a problem with the motor encoder, circuit or the PCB/connectors. ?If the RA motor starts to run then the problem is inside the Gemini CPU: either a bad connector or malfunctioning encoder circuit.

Regards,

? ? ?-Paul

Dave

the standard hand controller socket for all versions of Gemini.?

I think the only difference for G1 is it’s 5V not 3.3v. This is the power pin to the HC.?

If you need further Help just say
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Brendan

Hi all, I hope somebody can help?

I picked up a used GM-8 with Gemini 1 about 6 weeks ago. After finally sorting everything out with serial cables, weights etc and having tested it all indoors, tonight was the first light for the mount and scope (a WO ZenithStar 61 and imaging rig)

when I had set it all up and powered on, the dec axis immediately started to rotate in a clockwise manner and would do so until I powered off! Nothing I could do on the hand controller worked and I had not yet connected the ASIAir on the serial port.

I have removed and reseated the dec and RA motor cables, but the same still happens.?

Anyone got any ideas? I searched this forum and the wider we’d, but nothing seems to be forthcoming!

thanks

开云体育

Hi all, please can someone point me to the PIN allocation for the hand secondary hand controller socket, i have been given what I think is a home made unit but the wires are all wrong, only one of the buttons work and it operates the wrong axis.

Thanks

Thanks all, looks like I won't have to worry with my kit.

Hi all, thought I would share this too the group, I have designed a simple holder for the Gemini 1 hand set, I printed mine with a .8mm nozzle, it took 4 hours, in contrast using a .2mm nozzle it would take around 15 hours. The STL can be found on Thingiverse, here is the link.
?

On Tue, Sep 1, 2020 at 09:47 AM, Brian Valente wrote:

will be covering some of these in upcoming L

Thanks for the heads-up Brian.

After I got my new mount in February, I kept it under the cover of darkness.
It was inside the house, and only taken outside in the dark of night.
That lasted about 2 weeks....
Then one night this one solitary little dark cloud happened by, and it hung there long enough for me to take notice of it.
After that, we got 6 WEEKS of rain, with a few nights of clouds that didn't rain. I would have sworn Brush growing season was off due to drowning the brush!
Well, obviously it takes more than Biblical rain to kill the brush, given the fires we've had.
But in the long run, our mounts can outlive the weather. We may not like it, but so can we.
But I certainly share your frustrations Jim.

After the Spring rains, it seemed like the only time clouds shown up was at night.
And only after I was half way through, or just finishing my modeling.
Life's not easy for us at the bottom of the pond trying to look through the murk.

Better nights are coming.
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SonnyE


(I suggest viewed in full screen)

Hi Brian - Sorry,? I posted this to the wrong group.? I deleted the message but it looks like the subject wasn't deleted.

/g/AZ-Observing/topic/full_moon_no_clouds_or_smoke/76549758?p=,,,20,0,0,0::recentpostdate%2Fsticky,,,20,2,0,76549758

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Changing, and Checking, are two different things, Tony.
For example, I always use the Quick Start option when signing on so I can preview my settings.
To me, it gives me a chance to check my settings. But mostly to check myself.

Granted, the Quick Start does not specifically address the limits settings. Because you are correct, the safety limits do not arbitrarily change.
But once you become familiar with things, you gain confidence in the settings. (I do anyway. I like to take my time. After all, I'm retired so my time is worthless. LOL. And it helps me to remember things by checking them. (you could say I'm dumb. LOL!))

I put an RAEXT on my GM811G mount. It was to make it easier for this old geezer to transport it each night. But a big bonus was to image through a meridian flip.
I tested that and imaged a Nebula for 1,300 exposures (10s each) for 13,000 seconds in the stack. It was an experiment that paid off in spades.
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SonnyE


(I suggest viewed in full screen)

I thought the safety limits were standards that did not require changing?

That's a great setup! Make sure you get good filters - that's not the place to skimp. Both Chromas and Astrodons are great and I can personally vouch for Chroma's excellent customer service.

Also make sure your timezone is set correctly - that is something you need to set separate from the GPS (though glad to hear you are using GPS)


Brian

Hi Tony,
Have you tried to set the limits yet?


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SonnyE


(I suggest viewed in full screen)