COPYRIGHT © 1999 CANON INC. CANON 660/2100 REV.0 FEB. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)The machine’s photointerrupers may be checked either using a conventional meter orin service mode (by operating on the control panel of the printer unit). (If the reader unitis installed, you may use the control panel of the reader unit.)a. Using a Meter1) SET the meter range to 30 VDC.2) Connect the - probe of the meter to GND on the DC controller PCB.3) Connect the + probe of the meter to the terminals (on the DC controller PCB) indi-cated on the pages that follow.4) Make checks as indicated. (See the tables on pp. 10-5 ff.)b. Using Service Mode• Without the Reader Unit Installed (with the printer board installed)1) Connect the power plug to the power outlet; and while holding on the “Menu key,Enter/Online key, and Cancel key” on the control panel at the same time until “StartSELF-TEST” displays. The panel displays will show “Display” to indicate that servicemode has started after the printer unit checks itself.2) Using the Menu key on the control panel, select “SENSOR MONITOR”.3) Press the ENTER key to select “SENSOR MONITORING”.4) Check to make sure that “SENSOR MONITORING” has appeared on the first row ofthe display, indicating that at the mode in question has been selected.5) Turn on the sensor in question manually so that the result of monitoring will appearon the second row of the display.• The result of monitoring is indicated by means of a hexadecimal code (2 digits; eitherxx or yy group).Figure 10-101 Control Panel of the Printer UnitCHAPTER 10 TROUBLESHOOTING10-32 Checking the PhotointerruptersS E N S O R N GIROTINOMx y y zx zDownload free service manual at http://printer1.blogspot.com