I just pulled out my old Mac Plus (been stored in its original box for the last 4 years), plugged it in and it started with flashing question mark disk. Put a system disk into the drive and away it went.
Mouse was working and keyboard all going OK.
Next step was to boot it up from the external SCSI drive (which I have had working away happily on another machine). So I shutdown the Plus and it has the dialog with the restart button, floppy disk ejects. I turn around to get the SCSI drive and here this big POP sound, turn back and there is some smoke coming out the back of my beloved Mac Plus but the screen is still displaying the dialog box.
Is that likely to be a capacitor that popped?