Amiga Sparkler

Amiga RGB2HDMI test tool used to verify boards do not have sparkling artifacts.

Instructions

Just grab a binary from the bin folder and transfer to your Amiga and run it
Note that this tool has only been tested on Amigas with 3.1 ROMs, and it may not work on other versions
The default settings tend to show sparkles on boards that have issues (alternating pixels with a particular color combination on a hires non-interlaced screen).
Refer to the on-screen help for instructions on how to vary the test pattern (press the HELP key to toggle).
If you do see noise in the image, try the following RGB2HDMI settings changes by holding the button on your board to bring up the menu:
- Settings Menu->Overclock CPU: 40
- Settings Menu->Overclock Core: 170
- Sampling Menu->Sync Edge: Trailing with +ve PixClk
- Be sure to install a heat sink on your Pi as even the default configuration has some amount of overclocking
In my testing, most Amiga 2000 machines do not seem to need configuration changes, but Amiga 3000 machines more commonly do. Your mileage may vary.

These boards work well with no known sparkles in my testing (though some may require configuration changes as described above to eliminate noise).
After trying numerous variations on path length, eliminating through-holes, copper fills, regulator placement, etc. the predominant issue seems to be placement of U1 relative to the other chips.
If you can find a test pattern either from this tool or from some other source that exhibits issues, I would love to hear about it!
Learn more about the V1.1 boards here: https://github.com/Bloodmosher/Amiga-VideoSlot-RGBtoHDMI

These boards work pretty well with overclocking and the extra capacitor, but do exhibit problems on the test pattern:

These boards work pretty well in most circumstances but do do exhibit problems on the test pattern.
It would be interesting to see if the positioning of U1 could be changed (perhaps swap with the regulator?) to see if a similar outcome found on the Video Slot boards could be achieved.

I have not yet tried one of these but will post results as soon as I get one built.