Before revision: Empty turret board Turret board with a few components Turret board installed in chassis Turret boards were an early attempt at making electronic circuits that were relatively rugged, producible, and serviceable in the days before printed circuit boards (PCBs).
After revision: Nearly empty turret board Turret board with a few components Turret board installed in chassis Turret boards were an early attempt at making electronic circuits that were relatively rugged, producible, and serviceable in the days before printed circuit boards (PCBs).