LG MU-42PM12X Service Manual - Page 13

TROUBLE SHOOTING GUIDE 1. Power Board 1-1. General Power Flow Start check Doesn't the Yes screen whole come out? It is identical No with Power Off condition? Yes No 1. Check the Power Off condition. Is the Interface signal operated? Yes 2. Check the Interface signal condition. Doesn't the Yes low pressure output come out? No Doesn't the No Doesn't the No Doesn't the St-by 5V signal 5V Monitor signal VSC signal RL-ON come out? come out? come out? Yes 3. Check the St-by 5V signal circuit. Yes 4. Check the 5V Monitor signal circuit. Yes 5. Check the VSC RL-ON signal. Doesn't the Yes high tension output come out? Doesn't the VSC signal Vs-ON come out? No Doesn't the Vs, Va voltage output come out? Yes Yes No 7. Check the VSC Vs-ON 8. Check the Vs, Va signal voltage output circuit. No Doesn't the VSC low pressure output come out? Yes 6. Check the VSC low pressure output High tension Yes output voltage Drop it occurs? No Manufacture enterprise meaning of a passage When remove the Y, Z B/D Module Input Connector, Power Board high tension output voltage Drop it occurs? Yes 9. Check the Power Board Output high tension circuit When When remove the remove the No Y B/D Module No Z B/D Module Input Connector, output Input Connector, output voltage Drop voltage Drop it occurs? it occurs? Yes 10. Check the Z B/D Module Coutput circuit Yes 11. Check the Y B/D Module Coutput circuit - 13 -