[gary]

Originally Posted by Paul Haese

Gary, the earth from the main board is screwed into the recess of the inverter where the earthing screw is located. That screw is in direct contact with the heat sink which is supposed to be the earthing point. That cable is about 3 meters long. Then the earth travels back to the power point and back up to the house which is about 25 meters away.

Hi Paul,

I have in my mind the first iteration of how the inverter/motor system grounding might
be more ideally engineered and time permitting I will sketch it for you.
This then doesn't mean you should necessarily implement it in the way I suggest.
As I mentioned, grounding systems always require compromise somewhere.
However, hopefully it will illustrate some better practices that you can borrow from
if the other remedial steps you are taking still aren't sufficient for reliable
operation of equipment in your observatory.

Take heart that the term "ground" is one of the most misunderstood terms
in electrical engineering. Electrical Engineers working in different disciplines
within a system will use the term "ground" to mean different things.
So confusing it can be that I think if we could turn back time we would
happily purge the word altogether.

Cartoon attached below attributed to Bruce R. Archambeault, a Distinguished Engineer at IBM.

I don't know if the power supply is providing a perfect supply, but that might just be part of the problem. Below is a link to the power supply I bought. http://www.jaycar.com.au/productView.asp?ID=MP3096

The version I have is the 20amp supply.

Pretty hefty, but if you ever get the chance to use your multimeter to measure
the actual current draw of the gear you have connected to it, it might help
eliminate any surprises there.

Today I had a crash of the systems. The ST-I guide camera would not connect, not even the spare and the focusor would not connect either (but that is controlled by the mount hub pro). The main camera though is now connecting, but that has its own USB now. Next step is to go picking off each item until I have it sorted. I'll report back if I find what is going on here. Frustration is nothing compared to what I am feeling at present.

Sounds like Fred's anecdotal advice with his camera and the hub is good advice
and all you can keep doing is knocking these off one by one. There is always
a chance that more than one thing was going on here and in combination they
were enough to drop the overall system reliability.

Best regards

Gary