Guru
Joined: 09/08/2007
Location: AustraliaPosts: 4406
| Posted: 07:26am 14 May 2019 |
The original Step Inverter board revision 1.0 was only ever built as an initial prototype for myself to test some rather unusual ideas that I had.
I built myself one board, and to my amazement it not only worked very first go, it worked very well indeed. So I loaded a second board to use as a spare, out of the five that were made. And that was the end of it as far as I was concerned.
I had a working Warpverter, and I was now off grid with zero problems, and really happy.
However there were some minor details in that prototype that could have been better, but after all it was a very first initial prototype.
The first mistake was that I decided to add an extra 1uF tantalum capacitor to the +5v supply when I was laying out the board.
I made that C25, but it should really have been C19 as the next component designator in sequence after C18. There was also some issue with C17, but cannot now remember exactly what that was.
Second mistake was the polarity of C1 which has no + sign on the silk screen.
Third mistake was that the hole sizes for the screw terminal blocks were made far too large. None of these mistakes stopped it from working, and I just soldered in the components without giving it any further thought.
Suddenly and quite unexpectedly people were asking for boards, so I just sent out the revision 1.0 boards that I already had, with a correct bill of materials that listed C25 as 1uF and figuring that people would work out which way around C1 had to go.
I then ordered ten more boards revision 1.1 with the three errors fixed.
C25 became C19 as it should have been in the first place, and is a 1uF tantalum.
Whatever the issue was with C17 being duplicated was also fixed.
C1 gained the missing + on the silk screen.
And the hole sizes for the screw terminal blocks were reduced in size.
All the tracks and pads are fine. All of the issues really only concern component designators on the silk screen (and hole sizes).
I still have a few of these rev 1.1 boards and pre programmed proms available if anyone is interested.
The nano boards would be a better long term solution, but if you want to get something fairly basic working initially, this is arguably the very simplest way to get started.
Cheers, Tony.