Congratulations on solving the problem and I wish you many nice DXs. If you don't like to solder, I recommend using a power supply with current limitation.
It's likely that the previous owner forgot to put the RPi screws back in. If I remember correctly, they are M2.4x 8 mm or something similar.
I have a cooling fan, so I have an intermediate panel to hold it in place and for extra spacing I have M2.4x 10 mm screws.
--
Gyula HA3HZ
HA3HZ