Nah. That's probably glue to hold the caps in place under transport. BTW, how good are you at soldering? That motherboard you got should be SMT chip on it. 4Mb upgrade on that board is pretty easy (if you know what you are doing). You could change those original chips and run a wire between some leg...

Yes. 1,6mm on 4 or even more layers as well

PCB for cartridge port should be 1,6mm. But that is standard PCB thickness so shouldn't be a problem. You could also file the edge on both sides at 45 degrees to make the cartridge slide in a bit easier in the port.

1 left. Always programmed with the latest firmware available when shipped.

I don't know if it is practical but if you can route digital Red Green Blue + Hsync + Vsync +5v +gnd to a header (approx 16 pins) you could easily add HDMI output to the ATX back-plate (which would look like a gfx card) using a SiPeed Tang Nano 9k which are about $10 exactly - already inside :D The...

MAD9 should not be connected to RAS or anything else for that matter. Connect MAD9 from RAM board directly to MMU chip.

Good work! And welcome!

I'm selling my own plug-n-play version of the SidecarT project . It is not the official, but everything that is on the original is on my version but placement of components is different. Slightly shorter. I have 3 unit for sale. Raspberry Pico WH is included and soldered in place. No SD-card is incl...

Well, if the unit is working on other Ataris, it's probably your STe. Do you have good PSU? 5V is good? Changed caps on the PSU or is it the original 30y old one? Try changing the processor for a HC type . It fixes it for some people. You could also try and add 10K pullup resistors on the 8 data lin...