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AVX mount, serial connection issues with current firmware levels

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I can confirm that there are issues with connecting via serial to the Nexstar+ handset on the AVX mount with the latest firmware . I'm currently trying to guarantee the behaviour process I'm seeing but it's intermittent and that is annoying when trying to troubleshoot. I'm having problems in getting repeatability of the issues being seen, but this is the most consistent behaviour I'm getting.

The behaviour I'm seeing is:
With everything powered off, I connect up the cables between my SkyFi and the handset. I put the handset in the cradle so it doesn't move. I've previously modified the cradle to allow the serial cable free access to the handset port when connected.
I power up the SkyFi, and I confirm I have connection to my wifi router.
I power on the mount and awaken from hibernation, entering the date and time (without moving the handset from the cradle), and the mount sits at the standard prompt on the screen, and the mount has started tracking.
Trying to connect via SkySafari 4 on my tablet, I get an error that I can make the wifi connection but not to the mount itself.
Touching nothing else I gently tap the "2" button to get to the Stars menu, then I hit "back" and exit out of that submenu back to the main prompt.
Attempting to connect again on the tablet, I immediately get the telescope connection and it appears stable for the rest of the session.

It's not likely to cabling, as I've exchanged out all of the SkyFi to serial cabling, and I'm seeing computer serial port difficulties as well. If it were cabling it would not just start working each time at the same point when I've exited the submenu.It really does look as though the handset doesn't communicate on the handset serial port until submenus have been entered and exited from. 

As an aside, when the mount is pointing exactly at 90 degrees declination, it actually reports itself on the serial port as being at 0 degrees declination. Interesting way of avoiding the RA singularity at that point.

My mount's firmware levels are current as of January 10th at least.

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This sounds like a similar issue I am having with my Celestron AVX mount.

My thread is here


I have chased Celestron three times and have heard nothing. Logged a new call earlier, their after support is truly appalling. :angry5:

Since my post I switched the USB to Serial cable and that had no effect. I have a new serial cable on order from FLO but it is highly unlikely it will be that, so just throwing money down the drain!

My Firmware is currently:

HC: GEM 5.28.5300 - app version
Nex Star+ 3.1.5075 - Boot version
MC: 7.11.5056 - app version

Is that the same as yours?

I have seen your other post.

Hopefully we can join forces on this but I am beginning to suspect a new Hand Controller....

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I have a similar problem with the AVX and he original SkyQ WiFi.

It often reports that it has a connection, but that the mount i snot responding.

Being the SkyQ, I'm not conning through the hand controller - in fact, most times, it is not even connected - so I am wondering if it is hand controller related at all?

Be happy to hear of any solutions.

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Did you update your firmware recently? Was this then when the issues started? Is so you may have to downgrade the firmware. See other link for more info.

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HI All,

Did you fix this issue, I have a similar trouble with my CGEM. After flashing the Firmware HC (Nexstar+) , I am not able to see the MC.

HC: GEM 5.28.5300 (updated through CFM)

NexStar+ 3.1.5075 (Updated through CFM)

MC : ??.???.??  (before flashing HC the Motor Control version was MC: 6.50 6.50)




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I found that most of the USB to serial converters do not perform as they should, they s...
As far as I can see converters with a FTDI chipset are the only reliable ones, especially when the signal gets a bit complex.

I am not in bussiness with FTDI (regretably)


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