Dell 1320C major problems, please help

I have had errors for ages on my 1320C. I finally found out (apparently) I either have a faulty imaging unit (fuser replaced a year ago) or faulty transfer belt. PHD (imaging unit) was the most likely so i replaced that and now I just get sheets of paper plastered in toner (when only printing in mono).

I then removed the imaging unit and fuser unit. blew it all out with air compressor. wiped over the transfer belt with alcohol (oops, maybe shoudn't have done that), and now its cleaner, not tons of coloured toner everywhere, but instead even a test page only prints like this....