KenHahn

The X's like you see inside the symbols below typically denote a DRC error that needs to be corrected before fab. All SMD devices on the bottom side have these X's. Is there any chance that you flood filled the 12V plane on the bottom layer...

In his first paragraph he mentions melting plastic on the CPU, so probably safe to say "WAY TOO HOT". Seems like some kind of basic incorrect power issue to me. If you are using a footprint you found on-line, make sure that the pinout is...

Can't really tell from the partial schematics, but for instance you have a MUXBREAKOUT block with the only power pin being 5V that apparently has analog signals coming back to the Teensy on a different connection. Do you know if these are...

As already stated, you should only put 5V (3.6-5.5V) into the VIN pin. 3.3V is simply too low for it to function correctly. You show a possible connection to the VUSB pin. What is that connecting to if anything? Also make sure that none of...

I haven't used it, but the Ultimate Breakout GPS looks to be a 3.3V device with 5V tolerant inputs. https://www.adafruit.com/product/746 You can power it from 5V as it has a 3.3V regulator built-in, but you don't need to level shift the...

I was curious and have lots of test cases laying around, so I ran a few tests at132.9MHz as reported by the software using the PJRC PSRAM test combined with a simple Flash test that formats the Flash and writes/reads a file. 8MB APMemory =...

The 3144 Hall Effect sensor itself requires at least 4.5V power. Perhaps try powering the module from 5V and pull the output up to 3.3V as you have it for compatibility with the T4.0 to see if it helps to stabilize the readings.