Yeah I tried cleaning the edge card, no luck.
As a last ditch effort I tried something else, I don't know what made me think of it. If I press firmly inward on the card and hold it when I turn on the Lynx it works. It is like the card isn't thick enough to make good contact. Maybe I will try to shim the part with the 3dprinted Lynx SD logo and see if it works better.
I found that some of my ROMs don't work though. I load some and it says "programming" for a few seconds then dumps back to menu. Other games say "Programing" for a while then The Lynx shows "insert game" screen. Some work OK. Is there something special that needs to be done to the ROMs? These ROMs work in an emulator so I don't understand what could be wrong, they are all .LNX extension.