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Fixing a built-in dimmer on a desk lamp? Aka: Retrofitting a California CFL compliant lamp? Answered

I live in California and just bought a Pottery Barn desk lamp designed to dim. However, because of the new law requiring CFL-compliant lamps, the dimmer has been tampered with to prevent it from actually dimming, even though the switch is the original.

I opened the bottom and found the dimmer switch was encased in cardboard. I removed the cardboard, expecting this would fix the problem, but it didn't. Nothing else looks "tampered with." How can I make my lamp dim like it should

A picture of the guts is here: http://www.talesofthepack.com/wp-content/uploads/2012/03/lamp-guts-e1332022609831.jpg

And the model is here: http://www.potterybarn.com/products/architects-smart-technology-table-lamp/?pkey=ctask-lamps



Best Answer 7 years ago

A view of the other side of the circuit boar would be good.

I imagine the board was wrapped to insulate it from the lamp base (odd way to do that)

In general these simple dimmers are a thyristor (a kind of electronic switch) this turns the poser off for part of every cycle of the AC mains. Thus on average the bulb gets less voltage applied and is dimmer.

The knob sets how much of the AC cycle is turned off and so how dim the lamp will be.

Fault finding from a distance is difficult unless it is obvious.

there are lots of lamp dimmer circuits here



Answer 7 years ago

Thanks, rickharris for all the great info!

Here's a picture of the other side: http://www.talesofthepack.com/wp-content/uploads/2012/03/circuit-board.jpg

I went ahead and bought dimmer pack from ebay that seems like the same thing but designed to dim. Hopefully that should solve my problem.


7 years ago

Are you using a CFL bulb in it? If so those bulbs don't dim.


Answer 7 years ago

No, I'm using a regular incandescent and it still doesn't dim. The wiring underneath looks normal, so I imagine it the dimmer board that needs to be replaced.