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Can I just buy the Gemini 2 computer and HC or do I also have to buy the DEC and RA motors?

On Wed, Sep 20, 2023 at 03:43 PM, RAC Equipment Manager wrote:

Can I just buy the Gemini 2 computer and HC or do I also have to buy the DEC and RA motors?

Do your motors have DIN or RJ connectors (round or rectangle)? Gemini-1 motors will work with Gemini-2 as long as they have the DIN connectors, so you don't need to buy new ones.

Yes, i have the round din connectors.

Then all you need is the new controller and HC upgrade.?

That said the old Gemini 1 servo motors with smooth bodies are starting to wear out given their age. Failing Gemini 1 servo motors are being seen much more often recently of the problems we're seeing here and not easily recognized. Usually slightly strange behavior and errors on on axis that follow the servo motor when swapping to the other axis.?

If you need servos buy the full upgrade.?

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Chip Louie Chief Daydreamer Imagination Hardware?

? ?Astropheric Weather for Imagers - Click on my sig!

Before I make a jump to the Gemini 2 upgrade, I've ordered a Gemini 1 HC cable. I've tried replacing with a new HC to determine if that was the culprit. That didn't fix the problem of in-op DEC buttons so, I suspect the serial cable. To test the DEC cable and DEC motor I used an older non-Gemini HC (RJ45 cable) and the DEC and RA buttons work as they're supposed to.

Now it’s rare to lose both Dec buttons. ?Usually just one.?

The signal is a low voltage going to the CPU via a 3 pin 4148 diode on main board ?I cannot tell you which one (as I’m in hospital again) there are 4 near the HC cable socket on main ?PCB. 2 DEC 2 Ra.?

But there is a Deluxf HC drawing on the Gemini WEB IO site you can follow the appropriate lines press the HC button and measure the press going from 5V to 0v ‘ish).

But since it’s 2 DEC buttons then I suspect the cable is not seating properly into the socket. Did you get a Losmandy cable ?or DB15 From somewhere else?. ? These can have a plastic moulding that can interfere with the pins seating. Seen this a few times.?

The old plain HC routs a same “low” signal to the same diodes near the HC main PCB (from memory) . Since this works. ?I’m wondering if you HC Is losing 5 v internally effecting Dec? ? Which would be odd ? ?Just want to confirm you used another deluxe HC?

The outside HC led is from 5.4v but the diagram will show you where to measure for 5V.?

Since it worked ok with the plain HC I’d send it to Michael Herman in USA or David in UK I’m in Australia. ?

Cheers all I can do to help atm. ?Oh one thing does it work in DEC via RS232?

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Brendan

You sound be able to isolate the issue by swapping the RA and DEC din connectors at the Gemini? end.? If the DEC motor is controlled by the RA buttons with the plugs swapped and the RA motor is now not working using the Dec buttons the problern is in the Gemini box.? The G1 box can be repaired, or you can upgrade.?
If the Dec motor is not controlled by the RA buttons. The problem is the motor or the Din cable.? Test the Dec din cable by using it to connect the RA motor to the Gemini RA port.. If the RA motor works,? cable is good.?

I only had one DEC button (the top one) in-op. It went intermittent first before it failed. I did swap in another known good G1 HC and the same DEC button did not work. When I swapped in a non-Gemini HC w/RJ45 cable all buttons both DEC and RA worked appropriately. I have a G1 HC Serial cable coming. I'm confident that will fix the problem. If not, I'll do the upgrade to G2.?

Does pressing “REV DEC” fix that button or is it still the same. ?

If it stays “dead”….. it’s that button! ? Gone bad internal contacts.?

If the fault changes to bottom DEC button then it’s a signal problem, cable or internal HC or as I mentioned interface diodes on the main CPU. ?Could also be a CPU itself?

You should have said this from the first post as its thread stated as “G2 upgrade” now we are fault finding a G1!

The G1 can be fixed ? ?This is a type of fault the repairers have seen before. ?But it’s all up to you.?

cheers
FWIW?
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Brendan

I tried the REV DEC button to no effect except when scrolling through the menu. I can go up or down the menu using the one good DEC button by pressing the DEC REV button. pressing the DEC REV button does not change the position of the operable button. I have a new G1 HC serial cable coming.

Many thanks it sounds as if the HC “flex” button has gone bad. ?

You can test that with a multimeter on ohms. ?I can write for you a procedure to test the flex, buttons and how it all works ?

I do have some diagrams on my Google drive I can access and place up (drawings written guide) but are limited as am in hospital (and will be for a little while, only got out ICU (again) 2 days ago ….not unusual for me!).

But it gives me something to do and infact the way these buttons work is simple but time and moisture is ravaging them. ?

But you can test them in the HC (with multimeter on ohms and volts) and connected to the system on the main board ? IMHO this is looking less like a cable issue but I don’t have full facts to say this yet ?

cheers

Brendan

As suspected it was the G11 Gemini 1 HC cable. The new cable came today. Thanks to Tanya at Losmandy (HGM). Everything works as it's supposed to.

Many thanks for posting the result fix back. ?Its important thing many forget so kind always left wondering if I’m helping of hindering. ??

We never get the full picture sone times makes it hard so feedback is great?

thanks

cheers
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Brendan