Distributor issues

[devilhenge]

So I've been working on getting a Vauxhall Nova started for a bit now, and the issue seems to be with the distributor, as there is a strong spark from the coil when put near the engine block, but all the leads coming from the distributor only produce a weak spark intermittently. I have checked the points within the distributor, and they produce a small spark (compared to the spark from the coil), so I think they are fine. If so, what other issues could there be, and how would I go about troubleshooting them? (Just one thing, when I was trying to get the distributor working before, I tried to clean the rotor arms contacts with a piece of sandpaper. After reading up a bit on this, i now realise it was a stupid thing to do, but would the damage be enough to top the engine from firing?)