Acer A221HQV Acer A221HQV LCD Monitor Service Guide - Page 54

52 ACER A211H/A221HQ Go to contents page 5. Troubleshooting (continued) 5.3.6 Abnormal plug and play operation for VGA: Confirm the host computer supplies DDC/CI mode. Failure Point NG The host machine is not communicated in DDC/ CI mode. OK Check the voltage on CN302 pin 9, that is DC 5 V. Failure Point NG The VGA video cable is failure. OK Check the voltage on I303 pin 8, that is DC 5 V. OK Failure Point NG 1) Printed wire broke between I303 pin 8, D308 and CN302 pin 9. 2) D308 is failure. Check the signals if is high level on CN302 pin 12, 15, that is I2C data / clk signal. Failure Point NG The VGA video cable is failure. OK Check the output signal of I2C data / clk on I303 pin 5, 6. Failure Point NG I303 is failure. OK Failure Point 1) Printed wire broke between I306 pin 18, 19, I303 pin 5, 6 and CN302 pin 12, 15. 2) I306 maybe failure. 3) R331 or R332 is open. 4) C328, C329, D310, D311 is short.