In my experience, the LC doesn't respond to bumping; the LC II doesn't require it, either. On that note, the Classic and Classic II don't use it, either. I don't remember about any of the Mac II series, but they were soft-power so they either wouldn't boot period without a good PRAM battery, or would work without issue.
If an LC won't show signs of life, it could have a bad power supply. The voltages may be listed on the power supply's casing, so with a voltmeter it could be tested.
If an LC won't show signs of life, it could have a bad power supply. The voltages may be listed on the power supply's casing, so with a voltmeter it could be tested.
I've got a preproduction model, myself. Mine has a very large radial-lead capacitor soldered to the board (as opposed to surface-mounted) and then hot-glued to the top of the SCSI chip; it also has windowed EEPROMs marked "Apple Confidential" in place of the normal ROM chips. I bought it at a thrift store in Oregon maybe six years ago, along with an FDHD-upgraded Mac II. Too bad I didn't also buy that boxed Laser 128 (which, I found out later, was an Apple II clone) that I saw there later on... I'll upload a picture of the LC's logic board when I find it.