I'm trying to restore my dad's Ross to operational status. pretty much everything works great now except the front derailleur. I can't get it to move at all. I've adjusted the high and low set screws and I can feel the cable getting looser and tighter when I try to shift up and down, but the derailleur doesn't budge. Not even 1mm. Any ideas? I've even tried taking pliers and seriously yanking on the cable, to no avail.
It sounds like the problem is in the derailleur itself, not necessarily the cables. If you can't get the derailleur to move by pulling the cable, then maybe the der. is stuck/tight. Will the derailleur move just by pushing/pulling the der. body directly (not using the shifter or touching the cable)? A front der. should be sort of hard to move in your hand because there's a strong spring in it, but it should move. You can carefully pull on the der. cage plates a bit. (Be careful to not bend the der. cage.) If it doesn't move, try putting a penetrating lube (I like Tri-Flow) on all four main pivot points. Let it sit for a little while. If the thing still doesn't want to budge, you may have some rust in there. If it is very rusted, a cheap replacement der. might be the way to go.
Do you see any visible signs of rusting near the pivot points?
Is this an old double-crank derailleur? Are the shifters friction shifters? If so, you should be able to find an old front der. for just about free lying around in a used bike shop. You could simply replace this one if you can't get it to let go.
I'm guessing this is a clamp-on der. instead of a braze-on der. (a braze-on screws directly into the frame). If you replace the der., make sure you get one with the right clamp size. The clamp size is often written on the inside of the clamp.