Garmaine Staff asked 1 year ago

I've been asked to look at a CFL floor lamp. It's many (5-10) years old and one day stopped working; it simply didn't turn on. The fluorescent bulb (four short (5 inch?) tubes extending from a plastic base with a single four pin cluster) was taken to a store and it did work there, but the bulb's whereabouts is currently unknown.

Randomly probing between pairs of the four holes in the lamp socket at random shows between 5 and 15 VAC, but nearly zeros DC.

Is this lamp likely to have user-serviceable parts inside, like ballast for example? Or is the only course of action to buy a new CFL bulb and see what happens?

business end of a CFL floor lamp CFL floor lamp socket click for full size

update: based on helpful suggestions from @ I've opened the base of the floor lamp and there's a whole circuit board full of components!

There's a small fuse(?) labeled F1. My low quality DVM reads 0.7 Ohms when I touch the probes together and the same 0.7 Ohms when I touch them to either side of the fuse. Yes it's still in the circuit, but it at least suggests the fuse might be okay.

click images for full size

circuit board in a CFL floor lamp

circuit board in a CFL floor lamp circuit board in a CFL floor lamp

circuit board in a CFL floor lamp circuit board in a CFL floor lamp pair of BUL128A transistors