
How to Repair LED Lamps
The LED
circular lamp in our dining room  went off suddenly. This is after about 2 years
in operation.   One set
of two LEDs were found faulty.  This
 article
serves to share how to troubleshoot and repair this LED module.  The 
procedures described here can be used also on other types of LED lamps
How LED Lamp Works?
Unlike
normal fluorescent lamp,  LED lamp does
not have fluorescent tube nor ballast;  instead,   it has the following components
1.   The LED element;
2.   The LED  driver;
3.   The Aluminium heat sink.  
As current
flow through the LEDs,  it causes the
LEDs to give out lights.  Depending on the
size and power of the lamp,  a  LED driver can supply different wattages to several LEDs arranged in series.    In
 this case for the 18 watts circular lamp,  the driver will supply 48 
Volts to the LEDs.   Each LED will operate at around 3 to 3.6 Volts and
consume around 0.5 watts of power. There are about 36 LEDs in this 18
Watts lamp.   The LEDs are arranged in an array
as illustrated in the following
What can usually go wrong?
The LED
driver consists of very few components as shown.  
It is unlikely to have broken down as it is quite robust and reliable.   Most likely the LEDs are the ones at fault. 
What’s Needed?
There is no
special and expensive tools needed.   
Description 
 | 
  
Remarks 
(doubleclick to enlarge
  pictures) 
 | 
 
1.  Two numbers of 1.5 Volts AA or AAA battery,  improvised as LED tester 
 | 
  
Solder
  them up in series as shown 
 | 
 
2.  LED elements 
 | 
  
They are
  available from various online website such as AliExpress.  100 piece of common type of LEDs cost less
  than USD$1/= 
 | 
 
3.   Soldering tools 
 | 
  
Soldering
  irons and solders 
 | 
 
Repair Step by Step
Description 
 | 
  
Action 
 | 
  
Remarks 
(doubleclick to enlarge
  pictures) 
 | 
 
1.
  Inspection & testing 
 | 
  
1.  Go through by inspecting the LED one by
  one. 
2.  One could also light up the LED by touching their ends using the improvised LED tester.  
  The pair of LED should light up unless they are faulty. 
 | 
  
Faulty
  LED can be easily spotted by its burnt mark as shown 
 | 
 
2.  Unsoldering 
 | 
  
1.  Unsolder and remove the faulty LED from the
  board using the soldering iron.   
2. Carefully solder the new LED after having
  identified the locations of the Anode and Cathode and place it back into the correct position 
 | 
  
The
  cathode is identified by an additional plate at the end of the tips as shown 
 | 
 
3.  Final Testing 
 | 
  
1.  After soldering,  test the repair 
  using the improvised LED tester. 
 | 
  






