P-20: Ng (Abnormally High Bk Developing Efficiency; S-1: Ng (Ccd Clamp/Gain Adjustment Failure - Minolta CF910 Service Manual

(20) P-20: NG (Abnormally High Bk Developing Efficiency)

Step
1 Is the Toner Hopper turning abnormally
during a copy cycle?
2 Is the Black Hopper loaded with toner?
3 Are there any loose connectors?
4 Does "B/W Ratio" show 40 to 50% when
"Bk Toner Sup. Status" is opened from
"State Confirm" available from the Service
mode menu?
5 Is the PH window dirty?

(21) S-1: NG (CCD Clamp/Gain Adjustment Failure)

Step
1 Is any one of the gain values of 120 mm/s
in CCD Check "160 or more"?
2 Unplug connectors PJ1B, 2B, and 5B from
PWB-B, plug in the power cord, and turn
ON the Power Switch for shading opera-
tion. Check at this time to see if the mal-
function code is given when the Lamp is
OFF or ON.
Check Item
Check Item
T-104
Result
YES A. Check the wiring between
PWB-I and Toner Replen-
ishing Motor (Bk) M9.
B. Check the motor drive for
possible overload and, if it
is free of overload, change
M9.
C. If A. and B. have been
checked okay, change
PWB-I. (Change the Toner
Hopper as may be neces-
sary.)
NO Change the Developing Unit.
("Developer Change Mode,"
"Gradation Adjust")
If the malfunction code persists,
change PWB-I.
NO Add toner.
YES Reconnect the connectors.
NO Change the Polygon Motor
Drive Board, PWB-JA, and -JD,
and PH Upper and Lower Units
as a set. ("IR Area," "PRT
Area," and "Gradation Adjust")
YES Clean the window. ("Gradation
Adjust")
Result
YES Check the fuse in DC Power
Supply 2 PU2 or change PU2.
OFF Change PWB-B and PWB-C, in
that order.
ON Change PWB-A.
Action
Action