I recently acquired a IIGS and after booting into GS/OS it emits a repetitive clicking/ticking sound from the internal speaker. It also produces tones with pitches that vary depending on exactly what is selected in the GUI. I've found posts elsewhere (Clicking GS, IIgs ticking noise) which describe the behavior and reasons why it may be occurring. What I'm not sure about is whether this is a design limitation of ROM 1 GS systems, present from day 1, or if it's a defect due to some deterioration that's occurred since manufacture. I hear ROM 3 motherboards are unaffected, but can't find an answer as to whether a ROM 1 board's speaker will inevitably click even when functioning 100% properly. I suppose I'll try external speakers. It's an annoying sound, and I would have sought out ROM 3 had I known about it.