I think in a troubleshooting session, I may have done something unwise, and thus I think I fried the Teensy... At least it's not responding to anything at all now... So I don't know where the ultimate flaw in the system was.Just as info I did not read your other posts (no time right time sorry).
I'm sorry if this has been discussed before, but when I read what you describe here, I'd say the SD Card is not inserted.
I can't remember now 100% if it's the SD Card not inserted which does this or the firmware "test module", which means you should flash the last firmware on the Teensy again.
I could spend a long time trying to debug my soldering... However, I think I will try again fresh. Since I can re-use some of the parts on my current (Dead) module.. it won't be terribly costly.
So I have re-visited the BOM on Mouser, and Ordered all the parts I need (including a new Teensy).. I have those parts now,
The only component I can't get at Mouser right now is this: Linear Voltage Regulators 0.1A Pos Volt Reg
they are apparently on "Backorder" I suppose I can cannibalize it from my current failed module.
I ordered new PCB's from Thonk.. using the lowest cost Air Mail option... (yeah I'm cheap! Mail overseas is expensive!!!) So I'm still waiting for PCB's.