Charge Corona Current Adjustment - Ricoh FT5540 Service Manual

8.7 Charge Corona Current Adjustment

Optimum Adjustment Value: DC + 92.0 ± 1.0 µA
CAUTION: Make sure that the main switch is turned off when you touch the drum
shoe.
1. Reinstall the drum stay (1 screw and 1 knob) and the charge corona unit.
2. Position the drum shoe so that the axis of the current sensing plate [A] is aligned with the
charge corona wire [B].
3. Select the dc 200 mA range on the digital multimeter.
4. To turn on the charge corona, turn on the switching PCB dip switch corresponding to "C"
on the TC/SC power pack PCB. (The silk screen printed on the TC/SC power pack PCB is
correct.)
5. Adjust the corona current by turning VR "C" [C] on the C/B power pack. (Wait 30 seconds
for the current to stabilize.)
6. Confirm that the corona current at the front and the rear is the same by repeating the
above procedure with the drum shoe in different positions. If not, adjust the wire height
using the screw [D] on the front end block.
7. Remove the drum shoe, and reassemble.
8. Check copy quality.
5-67
31 August 1989