A long time ago, I was in a friend’s C140, returning to Springbank (CYBW) after dark. The radio had failed but the nav lights were working.
We joined the empty circuit and on final, looked for a light from the tower. No light so we went around. After two circuits, with no light, my friend decided to land anyway.
After we had shutdown, my friend called the tower. The tower guy was most apologetic. He saw us on the first approach and reached for the lamp to give us a green light. He explained that it had not been used for a long time and it fell apart when he took it off its hook!