Hello,

Last night, I encountered a recurring problem. I am attaching the log file. The Losmandy G11 Gemini 1 LV4 mount disconnects randomly from NINA. I have tried everything I could find in the group, but I haven't been able to fix the issue.

The first problem occurred after 8:18 PM; you can find it in the logs at 20:19:46.975 Exception.

Thank you in advance for your help.

Cyril

On Wed, Mar 19, 2025 at 06:27 AM, Cyril PIN-FERRIER wrote:

Hello,

Last night, I encountered a recurring problem. I am attaching the log file. The Losmandy G11 Gemini 1 LV4 mount disconnects randomly from NINA. I have tried everything I could find in the group, but I haven't been able to fix the issue.

The first problem occurred after 8:18 PM; you can find it in the logs at 20:19:46.975 Exception.

Thank you in advance for your help.

Cyril

On Wed, Mar 19, 2025 at 12:05 PM, Paul Kanevsky wrote:

Hi Cyril, the serial errors in logs (bad checksum, timeout, etc.) all indicate a bad, noisy, or unstable serial connection. Try changing PC to serial adapter, cables, clean the connectors on both sides. If the problem persist, try replacing USB->Serial adapter if you are using one.

Regards,

Hello Paul,

Thank you for the quick reply. I will start by checking the cables and cleaning the connectors. If the issue persists, I will consider replacing the USB-to-serial adapter, which is starting to get old. Regarding the adapter, is there a model that is better than others and easily available worldwide? (I am in France).

Thank you very much,
Cyril

On Wed, Mar 19, 2025 at 08:20 AM, Cyril PIN-FERRIER wrote:

Regarding the adapter, is there a model that is better than others and easily available worldwide? (I am in France).

I prefer the FTDI-based adapters. The drivers seem to just work, and even some of the older adapters have lasted for 15+ years and still work in my setup.

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Cyril,

I recently also had intermitttent communication problems with my G11/Gemini-1 (20 years old); I sprayed contact cleaner on the serial port on the Gemini and inserted and removed the serial cable several times. Magically, all my problems went away!

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Good luck,

-Joe

On Thu, Mar 20, 2025 at 07:39 AM, Joe Ulowetz wrote:

Cyril,

I recently also had intermitttent communication problems with my G11/Gemini-1 (20 years old); I sprayed contact cleaner on the serial port on the Gemini and inserted and removed the serial cable several times. Magically, all my problems went away!

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Good luck,

-Joe

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For those on RS232 ports by far the most common issue is the cable between the USB to serial converter.? A lot of folks used flat phone cabling with RJ/phone style connectors.? While cheap and good for long distances with the right type of flat cable they are much more fragile than a commercial style fully soldered DB9 and round shielded twisted pair cable.??

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So first identify the cable type used and diagnose as is appropriate, for flat phone RJ type cables and connectors clean the jacks first.? If that doesn't resolve it the issue may be the connection inside the RJ plug and the only way to fix that is to cut off the end and crimp a new RJ connector on the flat or round cable depending on what you have.?

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Alternately you can replace the cable but that's going to be harder unless you can fabricate a new cable yourself or have a friend who knows how to do this.??

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For a hand built soldered DB9 and shell check using round shielded twisted pair check continuity end to end and repair as needed.? Don't discount the possibility of dirty contacts but they are less of a problem for this type of connector.??

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Do this before you spend the money on a new USB to Serial converter cable.??

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Thank you all for your help. I cleaned the connectors and replaced the cable between the Gemini and the RS232 adapter. I will be able to run tests when the weather is okay, and if needed, I will replace the RS232 adapter.

Is the connector on the Gemini side an RJ22?

Hello Ciril,

Allow me to jump into this discussion to share my thoughts and also throw in a question for the group. I had the same issue a while back, and Paul pointed out the same solution. Needless to say, he was absolutely right — you really want to have a stable and noise-free connection between the mount and your control software.

In my case, I cleaned all the connectors with Sonax (any similar brand will do), and it helped reduce the issue (it happened fewer times). I've narrowed down the problem to the Gemini RJ port on the gemini board, and I noticed there's an alternative communication method through the hand control DB port that I haven’t tried yet ().

Here’s my question: Is replacing the RJ11 (11 or 12?) an easy fix for someone unskilled in electronics like myself, or should we go down the DB15 route instead? Good luck Ciril and thanks in advance for any additional comments on my inquiry. Guy