Don't leave it for any time with the coil energised, though I should think you realise that. With the older Williams games, bumpers and slingshots have 'Special' switches and driver circuits. When a game starts, or upon entering the diagnostics, one line from a PIA chip changes state, by dropping to 'low' (in fact, it goes 'high', but some gating logic sees it end up as a 'low'). This enables all six special driver circuits, and is also used to energise the flipper relay. If a special solenoid has its special switch closed (a 'low'), it'll energise at that moment. The slingshot probably has one of the switches touching the rubber band closed - at any rate, an input to a small gating chip on the driver board is low, and combined with the low from the 'Game On' line, that's switching the drive circuit. All the cpu and game program know about it is that the separate scoring switch, operated by the linkage arm, is closed.
