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

[ElectroCamillowski]

Well hello gentleman,

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.
It's a lamp with double dimmer. One for 200W halogen bulb ,and other for a small 12v halogen tiny bulb.
Thing is, upper big lamp is working perfectly, but small one is not working at all. I turn knob and nothing happens.
 
I disassembled it and checked two bronze wires, which go directly from dimmer unit to a bulb with tester and it shows 0V.

I want to repair it and learn something from that experience. Thing 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.
Thanks!

[IanB]

First things first. Did you check the fuse?

[ElectroCamillowski]

Yes. Fuse was checked at the beginning.It's good.
Its a two dimmers in one device kind of thing. Big bulb is operating. Only small is not.