Lexmark 11A4006 - Optra K 1220 B/W Laser Printer Service Manual page 46

Print Quality - Light Print
FRU
1 Transfer
Corona
2 HVPS
2-16
Action
Check the transfer corona for dirt or damage.
Check the contact and contact spring for pitting or
contamination. Clean or replace as necessary. Also
see the "Transfer Corona Service Check" on
page 2-29.
Check the contact spring and HVPS contact for pit-
ting, cable interference, or incorrect installation.
Clean if necessary.
Check the voltages on the engine board at the fol-
lowing locations;
Printer Idle:
CNMC-B10 = +24 V dc
CNMC-B11 = +17 V dc
CNMC-A11 = +20.5 V dc
CNMC-B12 = +0.1 V dc
Printer Printing:
CNMC-B10 = +0.1 V dc
CNMC-B11 = +0.1 V dc
CNMC-A11 = +0.1 V dc
CNMC-B12 = momentarily jumps up to 5 - 15 V dc.
If these voltages are not correct, replace the engine
board. If they are correct, replace the following
FRUs in the order shown:
1. Transfer Corona
2. HVPS
3. Interconnect Board