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Finicky ULN2803 Darlington driver

So I've been using the darlington driver in the 28x1 starter kit, which has been quite nice. When I decided to build my own circuit, I moved the chip to my new board, with the EXACT same vcc and ground hookups, and get nothing.

What I'm curious about is does this chip's leads need to be all connected? I just have ground, vcc, input 1, and output 1 hooked up. Like a chip that even if you only use one pin, the other need to be connected to something to tie it down to a high or low output?

My head hurts from trying to figure this out. Any help would be appreciated!

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Ugh, it was just messing with my head now. I put the chip back in, powered up, and now it works.

I'm not touching the damned thing anymore. 

A Picture says a 1000+ words..

My whole circuit was set up with a common ground. I guess I'll just have to set up a separate circuit on my breadboard and mess around with it.

Just very aggrivating :P

I checked the datasheet for ULN2803.  A common ground is a good idea and although you don't need to ground unused inputs it is good practice. How have you connected pin 10?
Just wondering if the ground for the ULN2803 is connected to the ground of the signalling device?  Only reason I'd see. Also that the ground and Vcc connections are in an unexpected place pins 9 and 10 across ffrom each other, rather than diagonal as some logic chips are. I would expect only one driver to work on it's own. You could try grounding the other inputs and see if that helps.