Acer A221HQV Acer A221HQV LCD Monitor Service Guide - Page 26

24 ACER A211H/A221HQ Go to contents page 5. Troubleshooting (continued) 5.1.3 Checking the back light unit: Is +22V supplied to inverter PWB? (by the power board) OK NG Failure Point Power board of Inverter part failure. Check the BKLT_EN signal of the DC input P301 pin 2 at TTL high level. OK NG Check the BKLT_ADJ signal of the input P301 pin3 from I308 pin102 is a PWM signal. Failure Point 1) printed wire broke between P301 pin2, R304 and I308 pin101. 2) I308 is failure. OK NG Failure Point 1) Back light unit of LCD module is failure. 2) Inverter Cable disconnect Failure Point Printed wire broke between P301 pin3, R501 and I308 pin102.