Ricoh FT7770 Service Manual page 292

5.
Mount the drum shoe [A] on the shaft and with the front edge 240 mm
from the front of the shaft.
of the machine.
6. Reinstall all corona units.
7. Install the drum stay and lower the top unit.
8. Connect the positive lead of the digital multimeter to the red shoe lead
[B]. Connect the negative lead of the multimeter and the black shoe
lead [C] to ground.
9. Set the meter for dc µA or ac µA depending on the corona current to
be measured.
Use SP 11 or 12 to turn on the coronas.
Note:
The drum currents vary with environmental conditions such as humidity and atmospheric
pressure. Generally it is not necessary to adjust the drum current because they have
already been adjusted for a range of environments at the factory. Drum current
adjustment may be required when there are problems with paper separation, incomplete
toner transfer or imege density. The drum current adjustment is also required when
the power pack is replaced.
OPTIMUM VALUE mentioned in the following pages was measured by
BECKMAN 3030 or 330.
Route the wire out through the left side
5-79
30 April, '89