8 rows active (~12.5% duty cycle):
|1) 12.5% duty cycle, quite dim, but still alright with LED's. Incandescent bulbs barely light up.|
1 row active (100% duty cycle):
|2) 100% duty cycle. Everything works peachy, including incandescent bulbs.|
When all rows are active the voltage is roughly 1.2V, thanks to the ghosting - otherwise it would be lower. This is with 5V input. To get it as bright as it should be I think I'd need to go up to 30-48V for 5V actually, which requires separating the logic chain voltage from the drive voltage.
And even weirder - the LED doesn't light up much at all when using the 12V line, so it looks like something is wrong there (probably programmatically, as that row requires special handling etc).
Welcome to nightmareland. :/