I hope someone can advise me. I'm trying to insert an F40 bulb (1.5" diameter, 4' long) into the socket shown below. With every other fluorescent socket in my home, I simply orient the two bulb pins vertically, push the bulb up into the socket, and then rotate the bulb 90 degrees. But as the photo shows, I can't insert the bulb vertically, because that path is blocked. I must be missing something obvious... can anyone help me? Thank you!


socket photo


Yeah, that's just a wacky "feature" of this particular type of tombstone.

Yes, that little black sleeve rotates independently from the white tombstone. In theory, it's supposed to be impossible for it to be in that position - since you would have had to turn it 90 degrees to remove the tube. However, if the tube broke or was cleverly removed in some other way, it could wind up like that.

So, you need a "key" to turn it 90 degrees. The key looks exactly like the end of a fluorescent tube, and I bet you have one of those :) You just stick the tube almost into position to install it, and land only that end on that tombstone. Turn it 90 degrees (should be a small detent) and you're all set.


You insert the tube into the socket (the black ring in your picture) on both ends of the fixture such that the prongs are in the 12 and 6 o'clock positions. Then you gently rotate the tube 90 deg so that the prongs are in the 3 and 9 o'clock positions. In this position the prongs then make contact with the brass colored fingers in the socket.

  • The black ring needs to be positioned so that the pins can be inserted and slid up in the 12 and 6 o'clock positions. – Alaska Man Apr 19 '20 at 18:09
  • So IIUC, I can't just insert the bulb, right? My problem appears to be identical to this: diy.stackexchange.com/questions/85291 . First I have to somehow rotate the black ring 90 degrees, and then I can insert the bulb by sliding it in vertically in the usual way. Is that correct? – David E Apr 19 '20 at 18:22
  • "IIUC", ? is that is an abbreviation ? I do not speak abbreviation. "rotate the black ring 90 degrees" YES. – Alaska Man Apr 19 '20 at 18:35
  • Yes, sorry... it's an abbreviation. IIUC = "If I understand correctly" . Thanks so much for your help! – David E Apr 19 '20 at 18:36
  • @DavidE I am old enough and curmudgeony enough that i use actual words. If this answer is correct please select it as so. – Alaska Man Apr 19 '20 at 19:23

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