31. DC power supply is absent.COPYRIGHT © 1997 CANON INC. CANON NP6350/NP6251 REV. 0 JULY 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)CHAPTER 11 TROUBLESHOOTING11-100CauseAC powersupplyWiring, DC loadDC powersupply PCBChecksIs the specified voltage presentbetween J301-1 and J301-5,between J301-3 and J301-5, andbetween J302-1 and J302-3?(J301 and J302 are in the DCpower supply unit.)Has the fuse (FU51, FU1) on theDC power supply blown?Turn off the power switch, and dis-connect the power plug. About 1min thereafter, connect the powerpug. Is DC power present whenthe power switch is turned on?Turn off the power switch, anddisconnect all connectors from theDC power supply PCB (J303,J304, J305, J306, J308, J309,J311). Turn on the power switch,and measure the voltage betweenthe terminals shown. Is it asindicated?However, the above assumes thatthe inaccuracy of the AC input is±10%.Step1234YES/NONOYESYESYESNOActionSee “AC power isabsent.”Remove the cause, andreplace the fuse.End.Turn off the powerswitch, connect one ofthe disconnected con-nectors, and turn on thepower. Repeat this for allconnectors to find theone which activates theprotection circuit. Checkthe wiring and DC loadsfrom that connector.Replace the DC powersupply PCB.ConnectorJ303J304J305J306J308J309J311Pin12324135711351312Output38VU38VU38VU24VR24VU24VU24VR5VR12VU24VU24VU24VA38VU24VU24VU224VA238VURemarks+10%,-7%+10%,-7%+10%,-7%±2%+10%,-7%+10%,-7%±2%±4%+10%,-7%+10%,-7%+10%,-7%+10%,-20%+10%,-7%+10%,-7%+10%,-7%+10%,-7%+10%,-7%Download service manual and resetter printer at http://printer1.blogspot.com
