Panasonic CF-74GCDADBM - Toughbook 74 - Core 2 Duo GHz Service Manual

4.2. TroubleshootingPlease take note of the following two points with regard to troubleshooting:1. Know-how of diagnosis upon occurrence of heavy troubles, e.g. ‘Set cannot be turned ON’, ‘Set fails to start’, ‘No display onscreen’, etc.2. Explanation of each trouble, mainly symptom of trouble in operation.Flow ChartNGNOYESNOYESNGNOYES NGOKOKNOYESNGOKNGOKNOYESOKOKNGSTARTSTARTPay attention to the following points when in pursuit of the cause of a troubleshooting.1. Peripheral apparatus connected with the set should all be removed before operation check.2. Make sure that cables, boards, etc. are not coming off, and recheck the contact condition.Set cannot be supplied with current.Power lamp fails to light up.ACAdaptor/BatteryOutput voltage Replace AC Adaptor/BatteryReturn set-up utility setpoint to the state of ‘delivery from factory’.Make sure of contact of K/B connector in use.Replace keyboard or main board.Replace DVD drive.Replace main board.Reinstall HDD.Replace main board.Power lampcheckCheck contact condition of power input terminal. Replace ifdefective.Check Power SW. Replace if defective.Inverter board Replace inverter board.Check inverter cable continuity. Replace if defectiveReplace LCD back light.BIOS operationcheck Replace main board (Check fuse at power source).LCD unitcheck Replace LCD unit.Result ofPOSTRefer to POSTerror code table. Replace main board.Main boardcheck Replace main boardHDD accessCheck HDD cable connection and continuity.Replace if defective.Replace HDD & Reinstall.Replace main board.Set-up utilitystarting Replace main board.Troublesymptoms on someof DVD or CDCheck if there are any flaws on DVD or CDmedia. Since flaws may appear on specificmedia, DVD or CD media can be defective.STARTENDDark display on screen.Screen fails to display.Failure in startingNot displayed properly on screen.Some or all keys cannot be input.DVD/CD CALL not practicable.Starts but operates unstably.Heavy trouble e.g.,‘Set cannot be turnedON’, ‘Set fails to start’,‘No display onscreen’, etc.Each kind oftrouble inoperation.*Clean DVD-ROM drive with an applicator.LCD backlight lighting4-2