So when I use Teensy processors, I have to use certain power supplies that I have on had. I cut the link on the Teensy to stop using the USB for power. However, with one of my power supplies when I have the USB connected to program the teensy and this particular power supply type (I have more than one and they all do the same) the teensy starts getting super hot right near the USB connection. Fortunately I have noticed this so it does not burn out but I suspect if I left it connected it might start on fire. When I just power the Teensy from the power supply alone, it is fine. Its only when its connected to the USB on my computer and the power supply. Anybody have any idea why this would happen?
@PaulStoffregen any idea here?
I wonder if you haven’t cut the link fully enough, and something is jumping
It won’t power the teensy via usb… and it has happened to more than one… but I will check that again
What type of power supply is it? Is it fully isolated?
@Justin_Eastman you might have your circuit ground floating in respect to mains earth.
Great video on that: https://www.youtube.com/watch?v=xaELqAo4kkQ
Although it’s worth watching the whole thing USB is covered from min 15.
Dunno. Pictures of the actual hardware & wiring would be worth 1000 words here…
@PaulStoffregen
really simple setup… just power and then wires to the leds. Everything works fine otherwise…
Let me know if you can see this…
https://plus.google.com/u/0/collection/YhplWB?cfem=1
@Justin_Eastman Not sure how you’re color coding your wires but the red going to ground (by the pushbutton) looks incredibly worrying.
@1icri_Old_Account
Its a great observation. However, it is a necessity with the way that the stupid JST connectors I got work. They have the red and black opposite to what the JST connectors are on the led pixels. The LEDs would not work if they were the other way around 
@Justin_Eastman I still believe you got a floating ground issue. Do you have a Laptop? Do not plug the laptop’s charger in and try USB again.
AND: you got a lot of dirt between µC pin 29 to 31 what happens to be PTA 13, Vdd and Vss.
@Juergen_Bruegl
I have my computer plugged into one power strip and the power supply plugged into another power strip and they both plug into the same wall circuit. Is that not a common earth ground? I have a bunch of other power supplies that work just fine. Its just this one type.
@Justin_Eastman Ah, okay. Just checking 
I see 4 photos close-up, but I can’t figure out which wires connect where, and I don’t see any connection to the LEDs.
@PaulStoffregen
5v goes to the positive on the power supply.
G is the ground and negative on the power supply. 11, 12, 17 go to data in on the strips. Strips grounds go to ground on the bottom of the board. Then the strips positve and negative go to the power supply. I cannot get the project open to photo any more than what I am showing. Sorry… Its more of an inconvenience than a problem. Just wondering if there is something I am doing wrong, I just don’t use those power supplies when loading programs…
Maybe something in there isn’t actually connected the way you think it is?
@PaulStoffregen
I cannot prove that is not the case but am pretty sure everything is good in there. If it was not, it would not explain why it works just find with my other power supplies and not the one in question.