HELP I'm stuck! Fixing halogen 12v dimmer.

Thread Starter


Joined Nov 17, 2015
Hey guys!

I have a problem. After bringing a standing lamp home from friend it turned out that small lamp is not working.
I decided to take a challenge and try to fix it.
I checked two bronze wires with tester and it shows 0V.
I want to repair it and learn something from that experience. Think is I have no clue what is broken or how to check it. I have multimeter, soldering iron and other necessary tools.

Description for photos:
-Lower dimmer is not working
-Brand of dimmer is Guang Hao CHZ-4100

Data of dimmer:
-Input AC230V-50Hz
-Output1(Big) AC230V, MAX 300W, MIN 50W
-Output2(Small, broken one) AC12V, MAX 50W, MIN 20W.

Please guide me how to check what's wrong and how to fix it :)

IMG_20160820_173749.jpg IMG_20160820_173755.jpg IMG_20160820_173807.jpg


Joined Apr 7, 2013
Not sure about your experience of repairing electronics, using tools such as multi meter.

But, here goes nothing.. Glad to see that you too are an enthusiast like me....

You can start by tracing the circuit backward from the copper wires. If you can use multimeter, please use the continuity range for tracing the circuit backwards.

From the copper wires, please trace backwards to see where the wires end. from that point, please see the components (capacitors, resistors, Transistors/FETs) involved and for any obvious bad component (Bulged capacitor, Burnt Resistor, Blown Transistor etc.).

This seems to be an SMPS circuit. Overall, this circuit is divided in 4 parts --> Input (AC 230V) --> Rectified to about 340 V DC --> HF Oscillator converts the rectified DC into desired AC. Here the AC frequency is higher.

Hope this helps as a starting point.

CAUTION: Please take extreme precaution and ensure that the circuit is not powered at any time when you are tracing it.
Last edited: