Nothing is actually getting hot on mine. Barely perceptible warmth would be a better way to put it.
I'm powering it directly from the USB port on my laptop.
Actually I just got a new laptop and it's doing the same thing as it was with my old one.
Just tried connecting it to a USB charging port that supplies 2.5A.
The USB cable is fairly substantial. It's not the kind with thin crappy wires. I know what you mean about those.
That had no effect on the problem.
I did a little more troubleshooting. The only test equipment I have available here is a multimeter.
VCC measures 4.7v.
Looking at the 74LS145, I went from Gnd to pin 1 which is C0(SW8) on the schematic. When I press the 8 button, it only pulls up to 2.2V. All the other buttons pull up to about 4v.
Mitch
