How to open 1969 fluorescent ceiling fixture

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Old 11-18-20, 11:45 AM
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How to open 1969 fluorescent ceiling fixture

I need to change the bulbs on a 4 foot fluorescent ceiling fixture in my laundry room that has not been opened in more than 20 years. I can't figure out how to get the lens off.

First I tried pushing up on the sides, thinking that it just hooked onto something, but that did not work. This cover is much more rigid than the one in my kitchen that opens like that.

Then I tried to remove the metal cap ends, as they seem to encapsulate the lens on three sides, but I only got as far as removing the screws. It didn't have any loosening effect anywhere I can see. I am unable to push the lens to clear it.





I have read somewhere that there might be some kind of latch above and inside the lens cover but I have not found it, and this space is very awkward to work in (big ladder in 6 foot room), so if someone could give me a clue as to where along this 4.5 foot exspanse I should concentrate my search efforts, I would be very grateful!

Thanks in advance for any suggestions.

Margaret
 
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Old 11-18-20, 11:51 AM
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Welcome to the forums.

Usually when there are screws on an end cap..... the end cap comes off.
Since you cannot get the end cap off..... the only other option is to lift one end of the lens slightly and slide the lens towards that end. It may be just caught by the end caps.
 
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Old 11-18-20, 12:06 PM
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Eh, we had one of these in our 1971 era office, PITA to deal with.
IIRC, the trick technique is to pinch the top of the cover at one end THEN slide it back.
So- let's say THIS is the profile of the lens. |____|
You want to GENTLY flex the the lens inward. /___\
Then IIRC, once the sides of the lens are no longer vertical, you can slide the lens
around 1/4 inch backwards into the cap, which pulls the other side of the lens back
around 1/4 inch, which brings is clear of the other cap and lets the lens drop down.

This MAY have been workable with the lens when it was new and flexible.
With 50 year old plastic, it probably is NOT as flexible, so, GENTLY try it.
BUT, be prepared to have the lens shatter and then go get a new light fixture.
 
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Last edited by Hal_S; 11-18-20 at 02:37 PM.
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Old 11-18-20, 12:11 PM
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Typically you get on the long side with a step ladder, grasp the long side of the lens with both hands spread out about 3 ft apart. With you fingers roll the top edge toward you with your thumbs on the bottom of the lens until it unhooks. Do this carefully, it's probably brittle.

You should be able to wiggle the end caps off if you removed the screws.
 
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Old 11-19-20, 04:50 PM
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Don't know if the OP figured it out yet, but I had that same fixture in a 1968 apartment I lived in years ago. You grab the lens, and slide it toward one end or the other of that frame, then you can swing it down. The lens is spring loaded and likely age-brittle, so be careful.
Andy
 
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Old 11-19-20, 05:37 PM
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Got it open!

You were all kind of right. This fixture contains the lens in two ways. The end cap had to be removed before anything else. I discovered this after nothing else worked and I got to wondering if the ends were stuck due to paint. So I climbed up there with a putty knife and a mallet and aimed at the place where the fixture end met the ceiling. The putty knife kept sticking and had to be pulled out with effort but eventually I dislodged whatever was holding the end on and finally I got that off.

Then I was able to slide the lens in that direction until it was stopped by the wall. And getting it half off its upper railing gave it the flexibility to be pushed up and then off the railing completely.

I got the burnt bulbs out and installed new ones but the new ones are only flickering to start. I assume that means I need a new ballast. Not surprising after 50 years, though.

I have installed a new ballast before in the kitchen but donít be surprised if I return for more help!

Thank you all!
 
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Old 11-19-20, 05:57 PM
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Older lights often had a starter... its a small silver canister. The end of it is about the size of a nickel and you twist it then pull it out. Easy to replace.
 
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Old 11-19-20, 06:43 PM
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Older than that, I think.

Thanks for offering help.

I have some indirect lighting fixtures that have starters but this one is much bigger. Probably 30 lbs of steel. The bulbs are on the sides and there is a big center section that is bolted up. Nothing is visible but the bolt threads and the nuts screwed into them. I feel pretty certain that when I release the nuts holding that bit up, that Iíll find a big ole ballast under there.
Having trouble uploading pics tonight to illustrate.
 
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Old 11-19-20, 08:35 PM
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If the pictures are too large they won't load.

It may be time to consider yanking that ol' ballast out of there and installing LED tubes.
You'd never have to get in there again.
 
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Old 11-19-20, 10:19 PM
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Lol! You had to mention the dreaded "L" word if you do that LED CRAP thing I can guarantee you will be in there again they are CRAP and do not last the rated life they are supposed to.

Sounds like a rapid start ballast if it truly from 1969 replace the lamps with F40T12 as that is what was common back then stay away from the "energy saving" 34Watt lamps those will kill an older rapid start ballast as they make it run hotter and thus fail. Rapid start fixtures do not require a starter.
 
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Old 11-19-20, 10:21 PM
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I am composing this on my phone. The system is just serving me a blank page (with no way out) when I select the picture icon. It should be serving me a choice of where to get the picture I want to upload. I did not have this problem when I first posted.

But in any case, I bought 4 replacement bulbs for this thing 15 years ago and am just needing to use two of them now. The bulbs I just took out have been in service for more than 20 years. They might only get turned on a few hours a month.

I replaced the kitchen fixture with a similar LED one because it is used all day, but I donít think I would get any economical benefit by switching this one at this time. The bulbs I have been waiting to install are 5000k daylight, so I wouldnít even get a lumen advantage.

But for future reference, is there a DIY way to convert this fixture to enable it to use LED bulbs? If so, I would like to know about it.

Thanks.
 
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Old 11-19-20, 10:30 PM
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CircuitBreaker, these are F40T12 Verilux bulbs.
 
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Old 11-20-20, 10:12 AM
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Pictures in case someone needs them in the future...


After the median metal cover was taken off.

Ballast

Ballast wiring diagram

Ballast product name

Ballast specs
 
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Old 11-20-20, 03:52 PM
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Nice those Verilux are premium quality lamps they have excellent CRI (Color Rendering Index) and are fairly bright.

If you really want to go LED get "direct wire Ballast bypass tubes" those are as the name imply's get directly wired to the 120VAC line without the ballast.

You have to read the instructions that come with them as they have all different methods of wiring them. for instance hot to one side an neutral to other or hot to one pin and neutral to the other and the other side is just there to hold up the "tube"

The ballast should have a letter and two numbers stamped on the bottom the letter is a Month code and the two numbers are the year minus the 19 prefix.
 
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Old 11-24-20, 08:53 PM
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Before changing the ballast, it never hurts to try another pair of lamps (if you have them). Also, sometimes new lamps can be a bit stubborn and it's possible they'll eventually start if you leave them on for a bit, though there's also a chance it could burn them out depending on the nature of the malfunction. With the power on (or off, but easier if on), try rotating each lamp slightly, not enough to remove it, but just a bit. If it's a bad connection, this may get it to fire up. Check that the sockets are in good condition and the lead wires are snug.
 
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Old 11-24-20, 09:37 PM
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Yikes. That is a scary picture.
Too many bad memories from being up on a ladder, swapping out a burned out ballast, and having "executive help" from my old boss -
"Why are you up on a ladder REPLACING those burned out bulbs IN THE DARK? ! I'll help you by TURNING ON THE LIGHT SWITCH..."
 
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