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Skywatcher Flextube Goto Precaution !!


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I recently "blew up" the motor board on my Skywatcher 300p flextube goto Dob by plugging an EQMod adapter into the wrong socket on there. 🥴

Thanks to extensive friendly help from members of this forum, 🍺 it has now been repaired, saving a great deal of money and a delay of several months for the parts to arrive from China.

In my defence, it's such an easy mistake to make that I wouldn't be surprised if other owners have made the same costly mistake.

The problem is that the main connection point, on the Alt axis plastic cover, has three connecting sockets.  A coax power, an RJ12 6 way for the Synscan handset, and an RJ45 8 way which is exclusively for the short linking cable that runs down to the AZ axis motor in the base.

This RJ45 socket is directly connected inside to the very sensitive PIC chip that contains the firmware, so almost anything else plugged into that socket in error will immediately destroy the PIC.

It's unfortunate that Skywatcher chose an RJ45 socket for such a sensitive connection because it is so common with other third party astro add-ons.  Even though it is clearly labelled, it's so easy to plug something else in, even in daylight, let alone in the dark.

In fact even most Synscan handsets usually have RJ45 plugs, whereas the Synscan handset for these goto Dobs has a special RJ12 plug, which goes into the socket right next to this RJ45.

I'm getting more forgetfull in my old age 🤓, and I want to make sure that I never make the same mistake again, (or anyone else using my scope), so I've added a small clamp to hold the plug into the socket semi-permanently, as it never really needs to be removed. (In fact it would have been far safer for Skywatcher to have fitted it as a permanent flying lead from the Alt motor cover.)

rj45 clamp.jpg

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I quite agree, it's so easy to plug the wrong device into the wrong socket, and that clamp will certainly prevent it happening, well done, and possibly something worthy of production as a sideline seeing that I've replaced three PIC microcontrollers now in as many weeks 🥴  

To be honest I can't see why Skywatcher doesn't either orientate the connection between the two boards so that its internal only connection, or as you say have a cable that is soldered directly to the ALT board with a RJ45 that plugs into the AZ board (as that only has one connector).  I can't see the reason for having the connection made externally unless an internal or direct connection would prevent the OTA from being removed from the mount.

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3 hours ago, malc-c said:

........ I can't see the reason for having the connection made externally unless an internal or direct connection would prevent the OTA from being removed from the mount.

The OTA lifts out of a large slot in the Alt axis drive pivot, leaving the electrics fully in situ and still operational.

The 2 foot long connecting lead has an RJ45 8 way connector at each end, linking the Alt plastic housing on the side with the AZ plastic housing in the base.

It then never needs to be unplugged at all from the 300p size and downwards, because the MDF base remains in one piece, even when the OTA is lifted off.

Even on the 350 and larger sizes, where the MDF base can be further dismantled for manouvering through doorways, (It's a monster !), it only needs to be unplugged from the AZ end.

The strange thing is that Skywatcher do use a completely different socket for exactly  the same purpose on their EQ5 Synscan mounts for connecting the Dec axis cover to the RA axis cover. On those it's a 7 pin circular DIN socket, a plug that is much more rarely seen on telescopes, so much less chance of confusion.



eq socket.jpg

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The wire to the motor would be better facing down as well. The number of times I've nearly snagged the loop on a door handle as I carry the base out.

It's now firmly strapped in place with some glued on cable ties.


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