Ricoh FW780 Service Manual - Page 154

4.8 DRUM CURRENT ADJUSTMENT NOTE: a) The drum currents vary with environmental conditions such as humidity and atmospheric pressure. Generally it is not necessary to adjust the drum currents because they have already been adjusted for a wide range of environments at the factory. b) Drum current adjustment is necessary whenever the power packs are replaced: adjustment may also be necessary to correct problems with paper separation, incomplete toner transfer, or image density. c) Make sure that the main switch is turned off when you change the range on the digital multimeter. If it is not, the multimeter may be damaged. d) There are variable resistors to change the charge currents, but they should not be changed. The drum currents should be adjusted by changing SP mode setting. Preporation 1. Remove the developer unit. 2. Remove the drum unit. 3. Remove the OPC drum from the drum unit, and install the current measurement drum [A] instead of the OPC drum. [A] A163 5-20 SM