Samsung SF-530 Service Manual page 48

All Black
All black in
printing area?
YES
Is transfer
voltage supplied
(-1.55 KV)?
YES
Is the
Hsync/ signal received
in LSU?
YES
Transfer part's contact
is bad -> Repair or
replace toner cartridge
Samsung Electronics
Does the
NO
video data line to LSU
transit to High/Low when
printing?
Replace LSU
NO
Repair or replace HVPS
NO
Replace LSU
NO
YES
Troubleshooting
Check the path among video
controller, engine board,
HVPS, LSU for the shortage
or open -> Repair or replace
the boards
4-15