Had parked for a week taking a course. Returned to field in the late afternoon, paid the fuel bill, then proceeded to do preflight. Undid the caps to check and only fumes visible. Went pack to office, VISA slip promptly torn up, but the fuel truck had just broken down; so had to do short flight to get gas in the dark.
Could not get second radio to work, even with the volume all the way up
The first radio was working; so called the destination tower.
After landing while getting gassed up, examined second radio more closely. The power switch was independent of the volume and not lit
That was my first night flight in that particular aircraft.
Sadly a few weeks later another pilot wrote it off after a PIO collapsed the nose strut.