Hi, I picked up some USB-powered cold cathode lights for cheap, and am considering using them for some basic task lighting at my computer desk. The idea is to take out the guts, wire them together, and either power them off a USB port, wall wart, computer PSU, etc.
Unfortunately, the lights are a little too feature-rich for my tastes. Instead of just turning on when I plug in the USB port, the light is controlled by a mechanical relay and two temporary microswitches. The first switch turns on the light, and the second turns the light off. I can't simply jump the on switch because it won't turn on if i hold down the on button as i plug it in. I must plug it in, then press the on switch, and the fixture will light up.
I'm pretty sure that with some basic testing, I could figure out how the switches and relay are wired, desolder those parts, and jump the right traces together to directly connect power to the rest of the inverter circuit. However, I'm wondering if doing so would be dangerous. This design seems to indicate that they want the lamp to be off when power is first applied. Are cold cathode tubes sensitive to power fluctuations (as might be expected when connecting a USB port)?
Also, why is the relay marked L2 on the PCB? I thought L meant inductor. Thanks!
Unfortunately, the lights are a little too feature-rich for my tastes. Instead of just turning on when I plug in the USB port, the light is controlled by a mechanical relay and two temporary microswitches. The first switch turns on the light, and the second turns the light off. I can't simply jump the on switch because it won't turn on if i hold down the on button as i plug it in. I must plug it in, then press the on switch, and the fixture will light up.
I'm pretty sure that with some basic testing, I could figure out how the switches and relay are wired, desolder those parts, and jump the right traces together to directly connect power to the rest of the inverter circuit. However, I'm wondering if doing so would be dangerous. This design seems to indicate that they want the lamp to be off when power is first applied. Are cold cathode tubes sensitive to power fluctuations (as might be expected when connecting a USB port)?
Also, why is the relay marked L2 on the PCB? I thought L meant inductor. Thanks!
