OK, that's what my multimeter schowed me: Resistance to Ground between V3.3 and VDDA test point is reliably 547 Ohm sweet Ohms +- 1 Ohmplease measure the resistance to GND. between the 3V3 test point and GND and also between the VDDA test point and GND.
What does it tell me though?
I soldered under a mganifying glass and checked everything multiple times under a magnifying glassCheck the decoupling caps (C1, C9, C10, C25, C26, C31) on the +3.3V power rail to see if any have a solder bridge underneath. Its usually apparent under magnification.
As far as I can tell there are no solder bridges under any of the above caps.
I do have solder bridges though. From what little I can tell from schematics I thought they should not be a problem. Here's what I have:
Looks like a solder bridge between D2 and L2 and another candidate for a solder bridge are L2 and R13, another possibility between C4 and R16. IC1 and IC5 look very clean. The solder stayed where it should.
And here's something else: While soldering the 7-pin display pins, some solder flowed into two pin holes of the row of 6 below. Counted from the left that is #3 and #5.
The best news is this: I'm meeting up with my electronics friend tomorrow and he's confident that we'll sort it out. That's why I'm holding off with pictures for the moment. I'm definitely going to report back what the mistake was so that people can avoid making the same mistake.