Streaks in prints

Re: Work centre 24
there is a 1/8'' streak aprox 3.75 inches apart on the whole print. The yellow drum was replaced after a yellow streak appeared in all prints. After the drum was replaced it appears that the printer is printing all colors in these streak except yellow.
Second problem: After several prints a slight cyan streak appears and gets worse with each print. These cyan streaks and at a 90 degree angle to the 1/8'' streaks in the first problem. The cyan streaks are aprox 1/2'' wide.
Please help if you can. I don't want to tear into this thing without knowing a little about what I'm looking for.