SHARP LL-T1815B
Manual de Servicio

PC-UM10M

THE PC DISPLAY DOES NOT WORK. (DIGITAL DVI)
Does the display work normally with analog inputs? 4 (Yes) Is 14Pin of CN2 at DC+5V? 4 (Yes) Are the signal levels of 1PIN, 2PIN, 9PIN, 10PIN, 17PIN, 18PIN, 23PIN, and 24PIN of CN2 changed? 4 (No) Are the waveforms at 1PIN and 2PIN of IC7 changed normally when the resolution is changed? 4 (Yes) Check IC7and IC8. 3 (No) Check IC7 peripheral circuits. 3 (Yes) IIC8 abnormality 3 (No) Check CN2 and the signal source. 3 (No) First, check with analog inputs.

THE FIRMWARE CANNOT BE UPGRADED
Connected to the analog input CN1? 4 (Yes) Is SW1 set to 1, 2 side? (CN1 side when viewed from you) 4 (Yes) Is 2PIN of Q16 at the GND level? 4 (Yes) Are 1PIN and 13PIN of IC6 changed normally? 4 (Yes) Are signal waveforms provided at 12PIN - 19PIN of IC18? 4 (Yes) Check 31, 32, 33, 35, and 44PIN of IC15. (If there is no abnormality, IC15 or IC19 is defective.) 3 (No) ICheck IC18 and IC19 peripheral circuits. 3 (No) Check IC6 peripheral circuits. 3 (No) Check SW1 and R258. 3 (No) Set SW1 to 1, 2 side (CN1 side when viewed from you). 3 (No) Connect the jig fro rewriting the firmware to the analog input CN1.

AUDIO DOES NOT SOUND
Is the audio cable connected to CN2 of the AUDIO PWB? 4 (Yes) Is 1PIN of CN1 at DC+12V? 4 (Yes) Is the voltage at 2PIN of CN1 changed by varying the sound volume? 4 (Yes) Are 3PIN and 4PIN of CN1 changed to the GND level when any display is made? 4 (Yes) Is 5PIN of CN1 at the GND level? 4 (Yes) Replace the AUDIO PWB. 3 (No) Check CN1, the cable connected to CN1, and CN3 of the main PWB. 3 (No) Check IC20 and its peripheral circuits. 3 (No) Check IC15 and its peripheral circuits. 3 (No) Check Q15 of the main PWB and the AU12V power line. 3 (No) Connect the audio cable to CN2 of the AUDIO PWB.

LL-T1815 TROUBLE SHOOTING

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