I originally posted this on my old website November 19, 2003.
PRESENTS
HOW TO FIX A LAMP
"I've found from past experiences that the tighter your plan, the more likely you are to run into something unpredictable."
- MacGyver
Here's the situation. You've just returned from helping your friend Jack Dalton with a rescue mission. Now, in order to get your attention, Jack had broken into your apartment and moved everything you own to his hangar. He promised to move it all back, but this is Jack we're talking about here. So now you've moved everything back yourself (It's amazing how much you can fit in a Jeep) and you're finally going to get a chance to relax. It's starting to get dark, so you plug the lamp in and turn it on...
The knob is supposed to click when you turn the lamp on, and then turn freely to adjust the light level. Instead of giving you a click, the knob simply turns. There is no click at either end of the knob's rotation. What's worse...the lamp isn't on either!
Jack Dalton strikes again! He must have broke the switch when he moved it. This lamp was too expensive to just throw out. You'll have to try and fix it. "Shouldn't be too bad," you think. "All I need is a new switch."
So you go to bed early, and the next day, you start on your plan to fix the lamp, which involves taking the lamp apart, taking out the old switch, taking it to get one just like it, and putting the new one in. FIGURE 1 shows the lamp, at the beginning of all this. You unscrew the top two pole sections and remove the not holding the switch in the hole. Now you get your first lock at the switch, which turns out to be attached to a circuit board. Connected to the circuit board are 6 wires, two going to the base and four to the fixture. You disconnect the wires (after labeling them to indicate their positions on the circuit board), and take the switch to the nearest hardware store (where you bought the lamp in the first place) in search of a replacement.
"Oh, we don't have anything like that."
"Nothing even close?"
"Nope, but you could try this one electrical supply place..."
After the third conversation like this, you realize you have three choices:
1. Go to the place across town the last electrical place suggested, even though there's no guarantee they will have the switch either. This will have to wait until at least tomorrow.
2. Contact the manufacturer of the lamp, if you can figure that out, and see if they have a switch. This would likely take several days (or weeks) to get the new switch, if they have any.
3. Get whatever switch you can get your hands on and fix the lamp yourself today.
It's pretty dark at your place without a lamp, so you decide to try #3. After all, you can fix anything!
Now, if this lamp simply had two wires coming from the fixture, this would be easy. However, this lamp has 4. You know you only need two of these; the other two are for the dimming function. But which are which?
First, lets take a look at the original switch and circuit board, and the wires, as shown in FIGURE 2. We won't concern ourselves with the layout of the board, or any of the other components on it. They just don't matter. The wires from the base are identical. They attached to terminals labeled "L" and "N." The other terminals, the ones the four wires to the fixture attached to, aren't labeled. Of these four wires, there are one white, one black, and two blue wires. Chances are, the black and white wires are the essential ones.
There is one sure-fire way to find out which wires connect to which: start connecting them and see what happens! Now, this might not sound like the best way to do this, but it's not like we're dealing with a bomb or anything. It's just a lamp. Your intuition tells you that "L" probably stands for "Live" or "Line" and "N" probably stands for "Neutral" or "Negative." Given that, you decide to try connecting the "L" wire to the white fixture wire and the "N" wire to the black wire. You twist one pair of wires together, then plug the lamp in and touch the other two together. Eureka! The lamp came on. Now you know how the lamp is wired. All you need now is a new switch.
The only switch you have on hand that will fit through the hole in the lamp pole is a small Single-Pole Single-Throw toggle switch. This switch has two positions, and is intended to be used to switch between one circuit and another. It has three terminals, but since there is only one circuit, you only need two of these. FIGURE 3 shows how to inset the switch into the circuit between one pair of wires. The other pair of wires can simply be soldered to each other. You should either wrap the extra terminal with electrical tape, or remove it completely, to avoid the possibility of a short circuit when the lamp is "off."
Now you can reassemble the lamp. Just one problem left. The switch is too small to fit snugly in the hole in the lamp pole. You need some way to make its diameter larger. The way to fix this is to wrap the switch with electrical tape until it fits snugly in the hole, as shown in FIGURE 4.
You can now finish reassembling the lamp. Getting the switch through the hole in the pole is a bit if a challenge, but it's not impossible. Once the switch is in position, you can reconnect the pole sections, and your lamp is once again in working order. Now, it won't dim anymore, so instead of a dimmable fluorescent lamp, you now have just a regular fluorescent lamp, but who really needs a dimmable lamp anyway? At any rate, it's certainly better than a lamp that doesn't work at all.
Isn't it amazing how a working lamp can brighten your day?