LightingYou will see this often
Seasonal light string
Also called fairy lights, Christmas lights.
A seasonal donation of thin wire and LEDs wired in series. One open LED darkens a whole section. The plug sometimes hides a rectifier and a blink controller.
A donor is the dead machine. The parts below are what is still worth removing from it. “Leave it” is a part that is physically in there and should stay in there: too dangerous, too worn, or only useful as part of a repair you are not doing.
A scrapped machine is a box of parts that failed at different times. The reason it was thrown out is often one bad piece. The motor, the cord, the supply, and the screws are frequently still good. This index says which is which.
Why it is in the trash while the parts are not
One dark section, or January.
Before you open it
Do this while it is still unplugged, cool, and not leaking. Unplug. Series strings are mains. Do not cut a live string to 'see the LED'.
Where the dead machine usually is
- Garage and shed — In the house
- Bulk trash day — Curb
January bulk trash. Test before you store another box of them.
How it comes apart
The controller is in the plug on LED sets. Incandescent mini-lights are a different, more annoying series circuit.
Tools: Meter.
Words on this page
- mains
- Ordinary household wall power. It can kill. Unplug before you open anything that used it, and do not experiment on live wiring.
- rectifier
- A set of diodes that turns alternating current (the wall, which reverses) into one-direction current. The output is still bumpy until a capacitor smooths it.
- series
- Connected in a chain. Cells in series add their voltages. LEDs in series all go dark if one of them opens.
What to take
The table is the short version. The notes under it describe that part inside this machine, not only the general description.
| Part | Call | How many | How often | Where to look |
|---|---|---|---|---|
| Indicator LED | Worth pulling | dozens | usually | The string. |
| Signal and hookup wire | Bonus | metres | always | Between lamps. |
| Bridge rectifier | Bonus | 1 | sometimes | In the plug. |
| Switch-mode wall supply | Leave it | 1 | sometimes | Some plug controllers. |
Worth pulling
Series LEDs. You cannot power one from 12 V just because the string said 12 V somewhere.
The string.
Cut a dark section out only after the string is unplugged, and know the rest of the series math.
One open LED per dead section.
Bonus
Thin, often 28 AWG or finer.
Between lamps.
Fine for signals. Not for current.
Insulation cracks on old sets.
A small rectifier.
In the plug.
Only if you open the plug.
Good.
Leave it
Not a general supply.
Some plug controllers.
Leave it.
Unknown.