Sharp MS722 Service Manual - Page 41

MD-MS722/C/W/MS721W TROUBLESHOOTING It is advisable to use the TEST mode (refer to Error Data Display Mode, P13) indicating the causes of troubles before starting repair. Causes of operation errors (up to 10 errors) are recorded as error codes. This information is useful for repair. When does not function When the CD section does not operate When the objective lens of the optical pickup is dirty,this section may not operate.Clean the objective lens,and check the playback operation.When this section does not operate even after the above step is taken,check the following items. Remove the cabinet and follow the troubleshooting instructions. "Track skipping and/or no TOC(Table Of Contents) may be caused by build up of dust other foreign matter on the laser pickup lens. Before attempting any adjustment make certain that the lens is clean. If not, clean it as mentioned below." Turn the power off. Gently clean the lens with a lens cleaning tissue and a small amount of isopropyl alcohol. Do not touch the lens with the bare hand. Is the power supply turned on when the remote control button or main unit button is pressed? Perform the check stated in item "Power is not turned on No when the PLAY button is pressed". Yes Does the display operate normally? Yes Perform the check stated in item "Abnormal display". No Is playback state set? Yes Perform the check stated in item "Playback state connot be No set". Is audio output normal? Yes Perform the check stated in item "Audio playback circuit". No Is recording/playback operation normal? Perform the check stated in item "Recording/playback No operation". • Power is not turned on when the / is pressed. button Is power turned on when the remote control pressed? button is No Is operation normal when the main body button is pressed? No Check the periphery of remote controller and main unit Yes headphone terminal (J703) and IC401. Is the pin 55 of IC401 in H state? Yes Are IC401 pin 3 set to "L"? Yes Does the pin 66 of IC401 oscillate? Check the position of Hold switch. No Check the DISC IN (SW901) switch of mechanism PWB. No Replace XL401. No - 41 -