i need a job as a technician riso machine.
I'm sorry but I don't have any documentation for the FT4615. I've only worked on the Ricoh digital line. But I can tell you that a white/light streak is usually caused by either an obstruction in the developer unit causing a low spot on the "developer brush" that contacts the drum surface or there is toner/dirt on the glass shield above the drum where the light passes through.