Dazor 2134 lamp only one bulb works

[SolarColumbia]

It's often called a draftsman lamp. It has two 18" fluorescent tubes. It's not the bulbs. I swapped in multiple new bulbs at the hardware store and only one will come on at a time. It's not specific to one side or the other. Sometimes one side comes on, sometimes the other side comes on, but only rarely do both come on. Would this be bad ballasts? Thanks.

 

[Bert_]

Manual preheat or starters? These usually use a simple choke ballast, hardly ever go bad.

 

[SolarColumbia]

I think these are manual preheat or if there is a starter it is perhaps in the switch? It's an older lamp although it has Phillip's type screws whereas another 2134 I have is slot head screws so likely older. There are 2 ballasts. If not the ballasts could it be the switch? If the ballasts are failing I'd rewire it to LED type B and remove the ballasts. Dazor has replacement switches for about $35 so if it's the switch I'll just replace it and stay with fluorescents.

 

[Bert_]

A starter is a little metal cylinder. Usually put in a pretty accessible spot since they wear out just like the bulbs

Is the switch just on/off? Or is it momentary where you hold down the on button for a few seconds?

 

[SolarColumbia]

You do have to hold down the button for a couple seconds or so for it to light. Here's a pic of the switch.

 

[BillK]

The problem sounds strange to me. Usually a lamp that uses a ballast does not require you to hold the switch down to get it started. The type that you have to hold the switch usually uses a starter like the one in the picture below.

The fact that is varies as to which of the two lamps works is also strange. It looks like the company is still in business. I think I would pick up the phone and call them before wasting a lot of money on switches or ballasts ? They should be able to tell you how to test it and figure out what the problem is.

Starter:
https://www.amazon.com/dp/B002DNAI4K/?tag=atomicindus08-20

 

[Bert_]

It's definitely manual preheat. Holding the button down is taking the place of a starter. A starter would make it automatic. Pretty common for these desk lamps.

I would be looking at the switch or lamp socket contacts. If you hold down the switch for a while do the ends of both lamps glow?

How long are you holding the start button? If you don't preheat long enough the lamps won't start reliably.

Those choke ballasts almost never go bad.

 

[rlitman]

You do have to hold down the button for a couple seconds or so for it to light. Here's a pic of the switch.

+1 My Dazor is manual pre-heat. You press and hold the red button until you see glowing ends on both lamps, then release, and they should both light. If you don't pre-heat, there's a good chance one lamp will not light.

 

[SolarColumbia]

Now matter how long I hold the button down, only the ends of one bulb glow, except one out of 20 or so attempts, and it can be either bulb. I'm thinking the switch is the culprit. I did send an email to Dazor a couple of days ago. If I don't hear back I'll call. Thanks for your help!

 

[SolarColumbia]

Well, one ballast definately looks burned and from what I've read that's a possibility. I didn't hear back from Dazor. I'm going to remove the ballasts and wire it for LED. I have to decide if I'm going single end or double end for ballast bypass LED.

 

[Bert_]

Well, one ballast definately looks burned and from what I've read that's a possibility. I didn't hear back from Dazor. I'm going to remove the ballasts and wire it for LED. I have to decide if I'm going single end or double end for ballast bypass LED.

You will have to get a different switch then. The momentary switch on the lamp not will not work.

The ballasts are very easy to check. Just use an ohm meter. If you have continuity, it's good! If it works at all then the ballasts are good. Preheat ballasts pretty much either work or they don't.

 

[SolarColumbia]

I'll check continuity on the ballasts but one looks cooked.

I have heard of these being rewired for LED using the original switch. There's a short YouTube also where a guy shows it functioning with LED tubes off the factory switch.

 

[Bert_]

Problem with the switch is it doesn't actually turn power on or off unless you are still holding the button.

You have power to the sockets all the time unless you hold the off button. When they are cold an f15t8/12 won't conduct with only 120v. Holding the start button connects power to the filaments and warms them up. When you release the start it creates a bit of a kick that combined with the warm filaments is enough to create an arc in the bulb. The ballast limits the current because the bulb will draw as much current as is available.

 

[SolarColumbia]

I'm certainly in over my head with this, lol.

 

[Bert_]

They are actually pretty simple. Here is basically what you have for a circuit. Yours is 2 lamp so the same thing twice.




I didn't draw one for off. When you push the black button it shuts off power, but only as long as you hold the button. When you release the button you will have 120V to the lamp again but it can't strike an arc across the cold lamp and so it stays off.