开云体育

I've just started gathering the parts for this project, but I noticed a detail that might be a factor in your measurements.
The Bag of Parts file contains the following line. This is also what appears on page 26 of the current version, ver 16, of manual section 2:

5V, 1.5A voltage regulator, TO-220

LM7812CT/NOPB-ND? (Digikey)

Please note that the LM7812 is NOT a 5V regulator, it's a 12V regulator. If you used the LM7812 instead of an LM7805, which IS a 5V regulator, then you might see approximately the voltage that you measured. This would exceed the Teensy's supply voltage spec.
Also in version 16 of manual section 2, on page 32, is a schematic section called "Voltage Regulators", which shows that Teensy +5V should come from an LM7805, not an LM7812.
I haven't found an LM7812 anywhere in the schematics. Make sure you've got an LM7805 and not an LM7812 at U2, the 5V REGULATOR location on the board. Also note that the BOM on page 25 has the +5v regulator listed as U4 rather than U2 as shown on the schematic.
My JackAl board doesn't show the U1, U2 part numbers in the legends that are printed on the circuit board- These locations are identified as "5V REGULATOR" and "3.3V REGULATOR".
U1, the +3.3V regulator, is shown in the schematic as an LM1117-33, but the 3.3V regulator in the part list of pate 26 is given as an LM1086-3.3. These are interchangeable, with same pinout and same noise spec, and slightly better input ripple rejection for the LM1117-3.3.